[v8,09/10] vduse: Introduce VDUSE - vDPA Device in Userspace

Commit Message

Yongji Xie June 15, 2021, 2:13 p.m. UTC

This VDUSE driver enables implementing vDPA devices in userspace.
The vDPA device's control path is handled in kernel and the data
path is handled in userspace.

A message mechnism is used by VDUSE driver to forward some control
messages such as starting/stopping datapath to userspace. Userspace
can use read()/write() to receive/reply those control messages.

And some ioctls are introduced to help userspace to implement the
data path. VDUSE_IOTLB_GET_FD ioctl can be used to get the file
descriptors referring to vDPA device's iova regions. Then userspace
can use mmap() to access those iova regions. VDUSE_DEV_GET_FEATURES
and VDUSE_VQ_GET_INFO ioctls are used to get the negotiated features
and metadata of virtqueues. VDUSE_INJECT_VQ_IRQ and VDUSE_VQ_SETUP_KICKFD
ioctls can be used to inject interrupt and setup the kickfd for
virtqueues. VDUSE_DEV_UPDATE_CONFIG ioctl is used to update the
configuration space and inject a config interrupt.

Signed-off-by: Xie Yongji <[e-mail]>
---
 Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +
 drivers/vdpa/Kconfig                               |   10 +
 drivers/vdpa/Makefile                              |    1 +
 drivers/vdpa/vdpa_user/Makefile                    |    5 +
 drivers/vdpa/vdpa_user/vduse_dev.c                 | 1453 ++++++++++++++++++++
 include/uapi/linux/vduse.h                         |  143 ++
 6 files changed, 1613 insertions(+)
 create mode 100644 drivers/vdpa/vdpa_user/Makefile
 create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c
 create mode 100644 include/uapi/linux/vduse.h

Comments

Jason Wang June 21, 2021, 9:13 a.m. UTC | #1

在 2021/6/15 下午10:13, Xie Yongji 写道:
> This VDUSE driver enables implementing vDPA devices in userspace.
> The vDPA device's control path is handled in kernel and the data
> path is handled in userspace.
>
> A message mechnism is used by VDUSE driver to forward some control
> messages such as starting/stopping datapath to userspace. Userspace
> can use read()/write() to receive/reply those control messages.
>
> And some ioctls are introduced to help userspace to implement the
> data path. VDUSE_IOTLB_GET_FD ioctl can be used to get the file
> descriptors referring to vDPA device's iova regions. Then userspace
> can use mmap() to access those iova regions. VDUSE_DEV_GET_FEATURES
> and VDUSE_VQ_GET_INFO ioctls are used to get the negotiated features
> and metadata of virtqueues. VDUSE_INJECT_VQ_IRQ and VDUSE_VQ_SETUP_KICKFD
> ioctls can be used to inject interrupt and setup the kickfd for
> virtqueues. VDUSE_DEV_UPDATE_CONFIG ioctl is used to update the
> configuration space and inject a config interrupt.
>
> Signed-off-by: Xie Yongji <[e-mail]>
> ---
>   Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +
>   drivers/vdpa/Kconfig                               |   10 +
>   drivers/vdpa/Makefile                              |    1 +
>   drivers/vdpa/vdpa_user/Makefile                    |    5 +
>   drivers/vdpa/vdpa_user/vduse_dev.c                 | 1453 ++++++++++++++++++++
>   include/uapi/linux/vduse.h                         |  143 ++
>   6 files changed, 1613 insertions(+)
>   create mode 100644 drivers/vdpa/vdpa_user/Makefile
>   create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c
>   create mode 100644 include/uapi/linux/vduse.h
>
> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> index 9bfc2b510c64..acd95e9dcfe7 100644
> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> @@ -300,6 +300,7 @@ Code  Seq#    Include File                                           Comments
>   'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                        conflict!
>   '|'   00-7F  linux/media.h
>   0x80  00-1F  linux/fb.h
> +0x81  00-1F  linux/vduse.h
>   0x89  00-06  arch/x86/include/asm/sockios.h
>   0x89  0B-DF  linux/sockios.h
>   0x89  E0-EF  linux/sockios.h                                         SIOCPROTOPRIVATE range
> diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
> index a503c1b2bfd9..6e23bce6433a 100644
> --- a/drivers/vdpa/Kconfig
> +++ b/drivers/vdpa/Kconfig
> @@ -33,6 +33,16 @@ config VDPA_SIM_BLOCK
>   	  vDPA block device simulator which terminates IO request in a
>   	  memory buffer.
>   
> +config VDPA_USER
> +	tristate "VDUSE (vDPA Device in Userspace) support"
> +	depends on EVENTFD && MMU && HAS_DMA
> +	select DMA_OPS
> +	select VHOST_IOTLB
> +	select IOMMU_IOVA
> +	help
> +	  With VDUSE it is possible to emulate a vDPA Device
> +	  in a userspace program.
> +
>   config IFCVF
>   	tristate "Intel IFC VF vDPA driver"
>   	depends on PCI_MSI
> diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile
> index 67fe7f3d6943..f02ebed33f19 100644
> --- a/drivers/vdpa/Makefile
> +++ b/drivers/vdpa/Makefile
> @@ -1,6 +1,7 @@
>   # SPDX-License-Identifier: GPL-2.0
>   obj-$(CONFIG_VDPA) += vdpa.o
>   obj-$(CONFIG_VDPA_SIM) += vdpa_sim/
> +obj-$(CONFIG_VDPA_USER) += vdpa_user/
>   obj-$(CONFIG_IFCVF)    += ifcvf/
>   obj-$(CONFIG_MLX5_VDPA) += mlx5/
>   obj-$(CONFIG_VP_VDPA)    += virtio_pci/
> diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile
> new file mode 100644
> index 000000000000..260e0b26af99
> --- /dev/null
> +++ b/drivers/vdpa/vdpa_user/Makefile
> @@ -0,0 +1,5 @@
> +# SPDX-License-Identifier: GPL-2.0
> +
> +vduse-y := vduse_dev.o iova_domain.o
> +
> +obj-$(CONFIG_VDPA_USER) += vduse.o
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> new file mode 100644
> index 000000000000..5271cbd15e28
> --- /dev/null
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -0,0 +1,1453 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * VDUSE: vDPA Device in Userspace
> + *
> + * Copyright (C) 2020-2021 Bytedance Inc. and/or its affiliates. All rights reserved.
> + *
> + * Author: Xie Yongji <[e-mail]>
> + *
> + */
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/cdev.h>
> +#include <linux/device.h>
> +#include <linux/eventfd.h>
> +#include <linux/slab.h>
> +#include <linux/wait.h>
> +#include <linux/dma-map-ops.h>
> +#include <linux/poll.h>
> +#include <linux/file.h>
> +#include <linux/uio.h>
> +#include <linux/vdpa.h>
> +#include <linux/nospec.h>
> +#include <uapi/linux/vduse.h>
> +#include <uapi/linux/vdpa.h>
> +#include <uapi/linux/virtio_config.h>
> +#include <uapi/linux/virtio_ids.h>
> +#include <uapi/linux/virtio_blk.h>
> +#include <linux/mod_devicetable.h>
> +
> +#include "iova_domain.h"
> +
> +#define DRV_AUTHOR   "Yongji Xie <[e-mail]>"
> +#define DRV_DESC     "vDPA Device in Userspace"
> +#define DRV_LICENSE  "GPL v2"
> +
> +#define VDUSE_DEV_MAX (1U << MINORBITS)
> +#define VDUSE_MAX_BOUNCE_SIZE (64 * 1024 * 1024)
> +#define VDUSE_IOVA_SIZE (128 * 1024 * 1024)
> +#define VDUSE_REQUEST_TIMEOUT 30
> +
> +struct vduse_virtqueue {
> +	u16 index;
> +	u32 num;
> +	u32 avail_idx;
> +	u64 desc_addr;
> +	u64 driver_addr;
> +	u64 device_addr;
> +	bool ready;
> +	bool kicked;
> +	spinlock_t kick_lock;
> +	spinlock_t irq_lock;
> +	struct eventfd_ctx *kickfd;
> +	struct vdpa_callback cb;
> +	struct work_struct inject;
> +};
> +
> +struct vduse_dev;
> +
> +struct vduse_vdpa {
> +	struct vdpa_device vdpa;
> +	struct vduse_dev *dev;
> +};
> +
> +struct vduse_dev {
> +	struct vduse_vdpa *vdev;
> +	struct device *dev;
> +	struct vduse_virtqueue *vqs;
> +	struct vduse_iova_domain *domain;
> +	char *name;
> +	struct mutex lock;
> +	spinlock_t msg_lock;
> +	u64 msg_unique;
> +	wait_queue_head_t waitq;
> +	struct list_head send_list;
> +	struct list_head recv_list;
> +	struct vdpa_callback config_cb;
> +	struct work_struct inject;
> +	spinlock_t irq_lock;
> +	int minor;
> +	bool connected;
> +	bool started;
> +	u64 api_version;
> +	u64 user_features;


Let's use device_features.


> +	u64 features;


And driver features.


> +	u32 device_id;
> +	u32 vendor_id;
> +	u32 generation;
> +	u32 config_size;
> +	void *config;
> +	u8 status;
> +	u16 vq_size_max;
> +	u32 vq_num;
> +	u32 vq_align;
> +};
> +
> +struct vduse_dev_msg {
> +	struct vduse_dev_request req;
> +	struct vduse_dev_response resp;
> +	struct list_head list;
> +	wait_queue_head_t waitq;
> +	bool completed;
> +};
> +
> +struct vduse_control {
> +	u64 api_version;
> +};
> +
> +static DEFINE_MUTEX(vduse_lock);
> +static DEFINE_IDR(vduse_idr);
> +
> +static dev_t vduse_major;
> +static struct class *vduse_class;
> +static struct cdev vduse_ctrl_cdev;
> +static struct cdev vduse_cdev;
> +static struct workqueue_struct *vduse_irq_wq;
> +
> +static u32 allowed_device_id[] = {
> +	VIRTIO_ID_BLOCK,
> +};
> +
> +static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa)
> +{
> +	struct vduse_vdpa *vdev = container_of(vdpa, struct vduse_vdpa, vdpa);
> +
> +	return vdev->dev;
> +}
> +
> +static inline struct vduse_dev *dev_to_vduse(struct device *dev)
> +{
> +	struct vdpa_device *vdpa = dev_to_vdpa(dev);
> +
> +	return vdpa_to_vduse(vdpa);
> +}
> +
> +static struct vduse_dev_msg *vduse_find_msg(struct list_head *head,
> +					    uint32_t request_id)
> +{
> +	struct vduse_dev_msg *msg;
> +
> +	list_for_each_entry(msg, head, list) {
> +		if (msg->req.request_id == request_id) {
> +			list_del(&msg->list);
> +			return msg;
> +		}
> +	}
> +
> +	return NULL;
> +}
> +
> +static struct vduse_dev_msg *vduse_dequeue_msg(struct list_head *head)
> +{
> +	struct vduse_dev_msg *msg = NULL;
> +
> +	if (!list_empty(head)) {
> +		msg = list_first_entry(head, struct vduse_dev_msg, list);
> +		list_del(&msg->list);
> +	}
> +
> +	return msg;
> +}
> +
> +static void vduse_enqueue_msg(struct list_head *head,
> +			      struct vduse_dev_msg *msg)
> +{
> +	list_add_tail(&msg->list, head);
> +}
> +
> +static int vduse_dev_msg_send(struct vduse_dev *dev,
> +			      struct vduse_dev_msg *msg, bool no_reply)
> +{


It looks to me the only user for no_reply=true is the dataplane start. I 
wonder no_reply is really needed consider we have switched to use 
wait_event_killable_timeout().

In another way, no_reply is false for vq state synchronization and IOTLB 
updating. I wonder if we can simply use no_reply = true for them.


> +	init_waitqueue_head(&msg->waitq);
> +	spin_lock(&dev->msg_lock);
> +	msg->req.request_id = dev->msg_unique++;
> +	vduse_enqueue_msg(&dev->send_list, msg);
> +	wake_up(&dev->waitq);
> +	spin_unlock(&dev->msg_lock);
> +	if (no_reply)
> +		return 0;
> +
> +	wait_event_killable_timeout(msg->waitq, msg->completed,
> +				    VDUSE_REQUEST_TIMEOUT * HZ);
> +	spin_lock(&dev->msg_lock);
> +	if (!msg->completed) {
> +		list_del(&msg->list);
> +		msg->resp.result = VDUSE_REQ_RESULT_FAILED;
> +	}
> +	spin_unlock(&dev->msg_lock);
> +
> +	return (msg->resp.result == VDUSE_REQ_RESULT_OK) ? 0 : -EIO;


Do we need to serialize the check by protecting it with the spinlock above?


> +}
> +
> +static void vduse_dev_msg_cleanup(struct vduse_dev *dev)
> +{
> +	struct vduse_dev_msg *msg;
> +
> +	spin_lock(&dev->msg_lock);
> +	while ((msg = vduse_dequeue_msg(&dev->send_list))) {
> +		if (msg->req.flags & VDUSE_REQ_FLAGS_NO_REPLY)
> +			kfree(msg);
> +		else
> +			vduse_enqueue_msg(&dev->recv_list, msg);
> +	}
> +	while ((msg = vduse_dequeue_msg(&dev->recv_list))) {
> +		msg->resp.result = VDUSE_REQ_RESULT_FAILED;
> +		msg->completed = 1;
> +		wake_up(&msg->waitq);
> +	}
> +	spin_unlock(&dev->msg_lock);
> +}
> +
> +static void vduse_dev_start_dataplane(struct vduse_dev *dev)
> +{
> +	struct vduse_dev_msg *msg = kzalloc(sizeof(*msg),
> +					    GFP_KERNEL | __GFP_NOFAIL);
> +
> +	msg->req.type = VDUSE_START_DATAPLANE;
> +	msg->req.flags |= VDUSE_REQ_FLAGS_NO_REPLY;
> +	vduse_dev_msg_send(dev, msg, true);
> +}
> +
> +static void vduse_dev_stop_dataplane(struct vduse_dev *dev)
> +{
> +	struct vduse_dev_msg *msg = kzalloc(sizeof(*msg),
> +					    GFP_KERNEL | __GFP_NOFAIL);
> +
> +	msg->req.type = VDUSE_STOP_DATAPLANE;
> +	msg->req.flags |= VDUSE_REQ_FLAGS_NO_REPLY;


Can we simply use this flag instead of introducing a new parameter 
(no_reply) in vduse_dev_msg_send()?


> +	vduse_dev_msg_send(dev, msg, true);
> +}
> +
> +static int vduse_dev_get_vq_state(struct vduse_dev *dev,
> +				  struct vduse_virtqueue *vq,
> +				  struct vdpa_vq_state *state)
> +{
> +	struct vduse_dev_msg msg = { 0 };
> +	int ret;


Note that I post a series that implement the packed virtqueue support:

https://lists.linuxfoundation.org/pipermail/virtualization/2021-June/054501.html

So this patch needs to be updated as well.


> +
> +	msg.req.type = VDUSE_GET_VQ_STATE;
> +	msg.req.vq_state.index = vq->index;
> +
> +	ret = vduse_dev_msg_send(dev, &msg, false);
> +	if (ret)
> +		return ret;
> +
> +	state->avail_index = msg.resp.vq_state.avail_idx;
> +	return 0;
> +}
> +
> +static int vduse_dev_update_iotlb(struct vduse_dev *dev,
> +				u64 start, u64 last)
> +{
> +	struct vduse_dev_msg msg = { 0 };
> +
> +	if (last < start)
> +		return -EINVAL;
> +
> +	msg.req.type = VDUSE_UPDATE_IOTLB;
> +	msg.req.iova.start = start;
> +	msg.req.iova.last = last;
> +
> +	return vduse_dev_msg_send(dev, &msg, false);
> +}
> +
> +static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to)
> +{
> +	struct file *file = iocb->ki_filp;
> +	struct vduse_dev *dev = file->private_data;
> +	struct vduse_dev_msg *msg;
> +	int size = sizeof(struct vduse_dev_request);
> +	ssize_t ret;
> +
> +	if (iov_iter_count(to) < size)
> +		return -EINVAL;
> +
> +	spin_lock(&dev->msg_lock);
> +	while (1) {
> +		msg = vduse_dequeue_msg(&dev->send_list);
> +		if (msg)
> +			break;
> +
> +		ret = -EAGAIN;
> +		if (file->f_flags & O_NONBLOCK)
> +			goto unlock;
> +
> +		spin_unlock(&dev->msg_lock);
> +		ret = wait_event_interruptible_exclusive(dev->waitq,
> +					!list_empty(&dev->send_list));
> +		if (ret)
> +			return ret;
> +
> +		spin_lock(&dev->msg_lock);
> +	}
> +	spin_unlock(&dev->msg_lock);
> +	ret = copy_to_iter(&msg->req, size, to);
> +	spin_lock(&dev->msg_lock);
> +	if (ret != size) {
> +		ret = -EFAULT;
> +		vduse_enqueue_msg(&dev->send_list, msg);
> +		goto unlock;
> +	}
> +	if (msg->req.flags & VDUSE_REQ_FLAGS_NO_REPLY)
> +		kfree(msg);
> +	else
> +		vduse_enqueue_msg(&dev->recv_list, msg);
> +unlock:
> +	spin_unlock(&dev->msg_lock);
> +
> +	return ret;
> +}
> +
> +static ssize_t vduse_dev_write_iter(struct kiocb *iocb, struct iov_iter *from)
> +{
> +	struct file *file = iocb->ki_filp;
> +	struct vduse_dev *dev = file->private_data;
> +	struct vduse_dev_response resp;
> +	struct vduse_dev_msg *msg;
> +	size_t ret;
> +
> +	ret = copy_from_iter(&resp, sizeof(resp), from);
> +	if (ret != sizeof(resp))
> +		return -EINVAL;
> +
> +	spin_lock(&dev->msg_lock);
> +	msg = vduse_find_msg(&dev->recv_list, resp.request_id);
> +	if (!msg) {
> +		ret = -ENOENT;
> +		goto unlock;
> +	}
> +
> +	memcpy(&msg->resp, &resp, sizeof(resp));
> +	msg->completed = 1;
> +	wake_up(&msg->waitq);
> +unlock:
> +	spin_unlock(&dev->msg_lock);
> +
> +	return ret;
> +}
> +
> +static __poll_t vduse_dev_poll(struct file *file, poll_table *wait)
> +{
> +	struct vduse_dev *dev = file->private_data;
> +	__poll_t mask = 0;
> +
> +	poll_wait(file, &dev->waitq, wait);
> +
> +	if (!list_empty(&dev->send_list))
> +		mask |= EPOLLIN | EPOLLRDNORM;
> +	if (!list_empty(&dev->recv_list))
> +		mask |= EPOLLOUT | EPOLLWRNORM;
> +
> +	return mask;
> +}
> +
> +static void vduse_dev_reset(struct vduse_dev *dev)
> +{
> +	int i;
> +	struct vduse_iova_domain *domain = dev->domain;
> +
> +	/* The coherent mappings are handled in vduse_dev_free_coherent() */
> +	if (domain->bounce_map)
> +		vduse_domain_reset_bounce_map(domain);
> +
> +	dev->features = 0;
> +	dev->generation++;
> +	spin_lock(&dev->irq_lock);
> +	dev->config_cb.callback = NULL;
> +	dev->config_cb.private = NULL;
> +	spin_unlock(&dev->irq_lock);
> +
> +	for (i = 0; i < dev->vq_num; i++) {
> +		struct vduse_virtqueue *vq = &dev->vqs[i];
> +
> +		vq->ready = false;
> +		vq->desc_addr = 0;
> +		vq->driver_addr = 0;
> +		vq->device_addr = 0;
> +		vq->avail_idx = 0;
> +		vq->num = 0;
> +
> +		spin_lock(&vq->kick_lock);
> +		vq->kicked = false;
> +		if (vq->kickfd)
> +			eventfd_ctx_put(vq->kickfd);
> +		vq->kickfd = NULL;
> +		spin_unlock(&vq->kick_lock);
> +
> +		spin_lock(&vq->irq_lock);
> +		vq->cb.callback = NULL;
> +		vq->cb.private = NULL;
> +		spin_unlock(&vq->irq_lock);
> +	}
> +}
> +
> +static int vduse_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 idx,
> +				u64 desc_area, u64 driver_area,
> +				u64 device_area)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +	struct vduse_virtqueue *vq = &dev->vqs[idx];
> +
> +	vq->desc_addr = desc_area;
> +	vq->driver_addr = driver_area;
> +	vq->device_addr = device_area;
> +
> +	return 0;
> +}
> +
> +static void vduse_vdpa_kick_vq(struct vdpa_device *vdpa, u16 idx)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +	struct vduse_virtqueue *vq = &dev->vqs[idx];
> +
> +	spin_lock(&vq->kick_lock);
> +	if (!vq->ready)
> +		goto unlock;
> +
> +	if (vq->kickfd)
> +		eventfd_signal(vq->kickfd, 1);
> +	else
> +		vq->kicked = true;
> +unlock:
> +	spin_unlock(&vq->kick_lock);
> +}
> +
> +static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,
> +			      struct vdpa_callback *cb)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +	struct vduse_virtqueue *vq = &dev->vqs[idx];
> +
> +	spin_lock(&vq->irq_lock);
> +	vq->cb.callback = cb->callback;
> +	vq->cb.private = cb->private;
> +	spin_unlock(&vq->irq_lock);
> +}
> +
> +static void vduse_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +	struct vduse_virtqueue *vq = &dev->vqs[idx];
> +
> +	vq->num = num;
> +}
> +
> +static void vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa,
> +					u16 idx, bool ready)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +	struct vduse_virtqueue *vq = &dev->vqs[idx];
> +
> +	vq->ready = ready;
> +}
> +
> +static bool vduse_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 idx)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +	struct vduse_virtqueue *vq = &dev->vqs[idx];
> +
> +	return vq->ready;
> +}
> +
> +static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,
> +				const struct vdpa_vq_state *state)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +	struct vduse_virtqueue *vq = &dev->vqs[idx];
> +
> +	vq->avail_idx = state->avail_index;
> +	return 0;
> +}
> +
> +static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
> +				struct vdpa_vq_state *state)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +	struct vduse_virtqueue *vq = &dev->vqs[idx];
> +
> +	return vduse_dev_get_vq_state(dev, vq, state);
> +}
> +
> +static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	return dev->vq_align;
> +}
> +
> +static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	return dev->user_features;
> +}
> +
> +static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	dev->features = features;
> +	return 0;
> +}
> +
> +static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,
> +				  struct vdpa_callback *cb)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	spin_lock(&dev->irq_lock);
> +	dev->config_cb.callback = cb->callback;
> +	dev->config_cb.private = cb->private;
> +	spin_unlock(&dev->irq_lock);
> +}
> +
> +static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	return dev->vq_size_max;
> +}
> +
> +static u32 vduse_vdpa_get_device_id(struct vdpa_device *vdpa)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	return dev->device_id;
> +}
> +
> +static u32 vduse_vdpa_get_vendor_id(struct vdpa_device *vdpa)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	return dev->vendor_id;
> +}
> +
> +static u8 vduse_vdpa_get_status(struct vdpa_device *vdpa)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	return dev->status;
> +}
> +
> +static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +	bool started = !!(status & VIRTIO_CONFIG_S_DRIVER_OK);
> +
> +	dev->status = status;
> +
> +	if (dev->started == started)
> +		return;


If we check dev->status == status, (or only check the DRIVER_OK bit) 
then there's no need to introduce an extra dev->started.


> +
> +	dev->started = started;
> +	if (dev->started) {
> +		vduse_dev_start_dataplane(dev);
> +	} else {
> +		vduse_dev_reset(dev);
> +		vduse_dev_stop_dataplane(dev);


I wonder if no_reply work for the case of vhost-vdpa. For virtio-vDPA, 
we have bouncing buffers so it's harmless if usersapce dataplane keeps 
performing read/write. For vhost-vDPA we don't have such stuffs.


> +	}
> +}
> +
> +static size_t vduse_vdpa_get_config_size(struct vdpa_device *vdpa)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	return dev->config_size;
> +}
> +
> +static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,
> +				  void *buf, unsigned int len)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	memcpy(buf, dev->config + offset, len);
> +}
> +
> +static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,
> +			const void *buf, unsigned int len)
> +{
> +	/* Now we only support read-only configuration space */
> +}
> +
> +static u32 vduse_vdpa_get_generation(struct vdpa_device *vdpa)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	return dev->generation;
> +}
> +
> +static int vduse_vdpa_set_map(struct vdpa_device *vdpa,
> +				struct vhost_iotlb *iotlb)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +	int ret;
> +
> +	ret = vduse_domain_set_map(dev->domain, iotlb);
> +	if (ret)
> +		return ret;
> +
> +	ret = vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
> +	if (ret) {
> +		vduse_domain_clear_map(dev->domain, iotlb);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void vduse_vdpa_free(struct vdpa_device *vdpa)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	dev->vdev = NULL;
> +}
> +
> +static const struct vdpa_config_ops vduse_vdpa_config_ops = {
> +	.set_vq_address		= vduse_vdpa_set_vq_address,
> +	.kick_vq		= vduse_vdpa_kick_vq,
> +	.set_vq_cb		= vduse_vdpa_set_vq_cb,
> +	.set_vq_num             = vduse_vdpa_set_vq_num,
> +	.set_vq_ready		= vduse_vdpa_set_vq_ready,
> +	.get_vq_ready		= vduse_vdpa_get_vq_ready,
> +	.set_vq_state		= vduse_vdpa_set_vq_state,
> +	.get_vq_state		= vduse_vdpa_get_vq_state,
> +	.get_vq_align		= vduse_vdpa_get_vq_align,
> +	.get_features		= vduse_vdpa_get_features,
> +	.set_features		= vduse_vdpa_set_features,
> +	.set_config_cb		= vduse_vdpa_set_config_cb,
> +	.get_vq_num_max		= vduse_vdpa_get_vq_num_max,
> +	.get_device_id		= vduse_vdpa_get_device_id,
> +	.get_vendor_id		= vduse_vdpa_get_vendor_id,
> +	.get_status		= vduse_vdpa_get_status,
> +	.set_status		= vduse_vdpa_set_status,
> +	.get_config_size	= vduse_vdpa_get_config_size,
> +	.get_config		= vduse_vdpa_get_config,
> +	.set_config		= vduse_vdpa_set_config,
> +	.get_generation		= vduse_vdpa_get_generation,
> +	.set_map		= vduse_vdpa_set_map,
> +	.free			= vduse_vdpa_free,
> +};
> +
> +static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,
> +				     unsigned long offset, size_t size,
> +				     enum dma_data_direction dir,
> +				     unsigned long attrs)
> +{
> +	struct vduse_dev *vdev = dev_to_vduse(dev);
> +	struct vduse_iova_domain *domain = vdev->domain;
> +
> +	return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
> +}
> +
> +static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,
> +				size_t size, enum dma_data_direction dir,
> +				unsigned long attrs)
> +{
> +	struct vduse_dev *vdev = dev_to_vduse(dev);
> +	struct vduse_iova_domain *domain = vdev->domain;
> +
> +	return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
> +}
> +
> +static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,
> +					dma_addr_t *dma_addr, gfp_t flag,
> +					unsigned long attrs)
> +{
> +	struct vduse_dev *vdev = dev_to_vduse(dev);
> +	struct vduse_iova_domain *domain = vdev->domain;
> +	unsigned long iova;
> +	void *addr;
> +
> +	*dma_addr = DMA_MAPPING_ERROR;
> +	addr = vduse_domain_alloc_coherent(domain, size,
> +				(dma_addr_t *)&iova, flag, attrs);
> +	if (!addr)
> +		return NULL;
> +
> +	*dma_addr = (dma_addr_t)iova;
> +
> +	return addr;
> +}
> +
> +static void vduse_dev_free_coherent(struct device *dev, size_t size,
> +					void *vaddr, dma_addr_t dma_addr,
> +					unsigned long attrs)
> +{
> +	struct vduse_dev *vdev = dev_to_vduse(dev);
> +	struct vduse_iova_domain *domain = vdev->domain;
> +
> +	vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
> +}
> +
> +static size_t vduse_dev_max_mapping_size(struct device *dev)
> +{
> +	struct vduse_dev *vdev = dev_to_vduse(dev);
> +	struct vduse_iova_domain *domain = vdev->domain;
> +
> +	return domain->bounce_size;
> +}
> +
> +static const struct dma_map_ops vduse_dev_dma_ops = {
> +	.map_page = vduse_dev_map_page,
> +	.unmap_page = vduse_dev_unmap_page,
> +	.alloc = vduse_dev_alloc_coherent,
> +	.free = vduse_dev_free_coherent,
> +	.max_mapping_size = vduse_dev_max_mapping_size,
> +};
> +
> +static unsigned int perm_to_file_flags(u8 perm)
> +{
> +	unsigned int flags = 0;
> +
> +	switch (perm) {
> +	case VDUSE_ACCESS_WO:
> +		flags |= O_WRONLY;
> +		break;
> +	case VDUSE_ACCESS_RO:
> +		flags |= O_RDONLY;
> +		break;
> +	case VDUSE_ACCESS_RW:
> +		flags |= O_RDWR;
> +		break;
> +	default:
> +		WARN(1, "invalidate vhost IOTLB permission\n");
> +		break;
> +	}
> +
> +	return flags;
> +}
> +
> +static int vduse_kickfd_setup(struct vduse_dev *dev,
> +			struct vduse_vq_eventfd *eventfd)
> +{
> +	struct eventfd_ctx *ctx = NULL;
> +	struct vduse_virtqueue *vq;
> +	u32 index;
> +
> +	if (eventfd->index >= dev->vq_num)
> +		return -EINVAL;
> +
> +	index = array_index_nospec(eventfd->index, dev->vq_num);
> +	vq = &dev->vqs[index];
> +	if (eventfd->fd >= 0) {
> +		ctx = eventfd_ctx_fdget(eventfd->fd);
> +		if (IS_ERR(ctx))
> +			return PTR_ERR(ctx);
> +	} else if (eventfd->fd != VDUSE_EVENTFD_DEASSIGN)
> +		return 0;
> +
> +	spin_lock(&vq->kick_lock);
> +	if (vq->kickfd)
> +		eventfd_ctx_put(vq->kickfd);
> +	vq->kickfd = ctx;
> +	if (vq->ready && vq->kicked && vq->kickfd) {
> +		eventfd_signal(vq->kickfd, 1);
> +		vq->kicked = false;
> +	}
> +	spin_unlock(&vq->kick_lock);
> +
> +	return 0;
> +}
> +
> +static void vduse_dev_irq_inject(struct work_struct *work)
> +{
> +	struct vduse_dev *dev = container_of(work, struct vduse_dev, inject);
> +
> +	spin_lock_irq(&dev->irq_lock);
> +	if (dev->config_cb.callback)
> +		dev->config_cb.callback(dev->config_cb.private);
> +	spin_unlock_irq(&dev->irq_lock);
> +}
> +
> +static void vduse_vq_irq_inject(struct work_struct *work)
> +{
> +	struct vduse_virtqueue *vq = container_of(work,
> +					struct vduse_virtqueue, inject);
> +
> +	spin_lock_irq(&vq->irq_lock);
> +	if (vq->ready && vq->cb.callback)
> +		vq->cb.callback(vq->cb.private);
> +	spin_unlock_irq(&vq->irq_lock);
> +}
> +
> +static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
> +			    unsigned long arg)
> +{
> +	struct vduse_dev *dev = file->private_data;
> +	void __user *argp = (void __user *)arg;
> +	int ret;
> +
> +	switch (cmd) {
> +	case VDUSE_IOTLB_GET_FD: {
> +		struct vduse_iotlb_entry entry;
> +		struct vhost_iotlb_map *map;
> +		struct vdpa_map_file *map_file;
> +		struct vduse_iova_domain *domain = dev->domain;
> +		struct file *f = NULL;
> +
> +		ret = -EFAULT;
> +		if (copy_from_user(&entry, argp, sizeof(entry)))
> +			break;
> +
> +		ret = -EINVAL;
> +		if (entry.start > entry.last)
> +			break;
> +
> +		spin_lock(&domain->iotlb_lock);
> +		map = vhost_iotlb_itree_first(domain->iotlb,
> +					      entry.start, entry.last);
> +		if (map) {
> +			map_file = (struct vdpa_map_file *)map->opaque;
> +			f = get_file(map_file->file);
> +			entry.offset = map_file->offset;
> +			entry.start = map->start;
> +			entry.last = map->last;
> +			entry.perm = map->perm;
> +		}
> +		spin_unlock(&domain->iotlb_lock);
> +		ret = -EINVAL;
> +		if (!f)
> +			break;
> +
> +		ret = -EFAULT;
> +		if (copy_to_user(argp, &entry, sizeof(entry))) {
> +			fput(f);
> +			break;
> +		}
> +		ret = receive_fd(f, perm_to_file_flags(entry.perm));
> +		fput(f);
> +		break;
> +	}
> +	case VDUSE_DEV_GET_FEATURES:
> +		ret = put_user(dev->features, (u64 __user *)argp);
> +		break;
> +	case VDUSE_DEV_UPDATE_CONFIG: {
> +		struct vduse_config_update config;
> +		unsigned long size = offsetof(struct vduse_config_update,
> +					      buffer);
> +
> +		ret = -EFAULT;
> +		if (copy_from_user(&config, argp, size))
> +			break;
> +
> +		ret = -EINVAL;
> +		if (config.length == 0 ||
> +		    config.length > dev->config_size - config.offset)
> +			break;
> +
> +		ret = -EFAULT;
> +		if (copy_from_user(dev->config + config.offset, argp + size,
> +				   config.length))
> +			break;
> +
> +		ret = 0;
> +		queue_work(vduse_irq_wq, &dev->inject);


I wonder if it's better to separate config interrupt out of config 
update or we need document this.


> +		break;
> +	}
> +	case VDUSE_VQ_GET_INFO: {


Do we need to limit this only when DRIVER_OK is set?


> +		struct vduse_vq_info vq_info;
> +		u32 vq_index;
> +
> +		ret = -EFAULT;
> +		if (copy_from_user(&vq_info, argp, sizeof(vq_info)))
> +			break;
> +
> +		ret = -EINVAL;
> +		if (vq_info.index >= dev->vq_num)
> +			break;
> +
> +		vq_index = array_index_nospec(vq_info.index, dev->vq_num);
> +		vq_info.desc_addr = dev->vqs[vq_index].desc_addr;
> +		vq_info.driver_addr = dev->vqs[vq_index].driver_addr;
> +		vq_info.device_addr = dev->vqs[vq_index].device_addr;
> +		vq_info.num = dev->vqs[vq_index].num;
> +		vq_info.avail_idx = dev->vqs[vq_index].avail_idx;
> +		vq_info.ready = dev->vqs[vq_index].ready;
> +
> +		ret = -EFAULT;
> +		if (copy_to_user(argp, &vq_info, sizeof(vq_info)))
> +			break;
> +
> +		ret = 0;
> +		break;
> +	}
> +	case VDUSE_VQ_SETUP_KICKFD: {
> +		struct vduse_vq_eventfd eventfd;
> +
> +		ret = -EFAULT;
> +		if (copy_from_user(&eventfd, argp, sizeof(eventfd)))
> +			break;
> +
> +		ret = vduse_kickfd_setup(dev, &eventfd);
> +		break;
> +	}
> +	case VDUSE_VQ_INJECT_IRQ: {
> +		u32 vq_index;
> +
> +		ret = -EFAULT;
> +		if (get_user(vq_index, (u32 __user *)argp))
> +			break;
> +
> +		ret = -EINVAL;
> +		if (vq_index >= dev->vq_num)
> +			break;
> +
> +		ret = 0;
> +		vq_index = array_index_nospec(vq_index, dev->vq_num);
> +		queue_work(vduse_irq_wq, &dev->vqs[vq_index].inject);
> +		break;
> +	}
> +	default:
> +		ret = -ENOIOCTLCMD;
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static int vduse_dev_release(struct inode *inode, struct file *file)
> +{
> +	struct vduse_dev *dev = file->private_data;
> +
> +	spin_lock(&dev->msg_lock);
> +	/* Make sure the inflight messages can processed after reconncection */
> +	list_splice_init(&dev->recv_list, &dev->send_list);
> +	spin_unlock(&dev->msg_lock);
> +	dev->connected = false;
> +
> +	return 0;
> +}
> +
> +static struct vduse_dev *vduse_dev_get_from_minor(int minor)
> +{
> +	struct vduse_dev *dev;
> +
> +	mutex_lock(&vduse_lock);
> +	dev = idr_find(&vduse_idr, minor);
> +	mutex_unlock(&vduse_lock);
> +
> +	return dev;
> +}
> +
> +static int vduse_dev_open(struct inode *inode, struct file *file)
> +{
> +	int ret;
> +	struct vduse_dev *dev = vduse_dev_get_from_minor(iminor(inode));
> +
> +	if (!dev)
> +		return -ENODEV;
> +
> +	ret = -EBUSY;
> +	mutex_lock(&dev->lock);
> +	if (dev->connected)
> +		goto unlock;
> +
> +	ret = 0;
> +	dev->connected = true;
> +	file->private_data = dev;
> +unlock:
> +	mutex_unlock(&dev->lock);
> +
> +	return ret;
> +}
> +
> +static const struct file_operations vduse_dev_fops = {
> +	.owner		= THIS_MODULE,
> +	.open		= vduse_dev_open,
> +	.release	= vduse_dev_release,
> +	.read_iter	= vduse_dev_read_iter,
> +	.write_iter	= vduse_dev_write_iter,
> +	.poll		= vduse_dev_poll,
> +	.unlocked_ioctl	= vduse_dev_ioctl,
> +	.compat_ioctl	= compat_ptr_ioctl,
> +	.llseek		= noop_llseek,
> +};
> +
> +static struct vduse_dev *vduse_dev_create(void)
> +{
> +	struct vduse_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> +
> +	if (!dev)
> +		return NULL;
> +
> +	mutex_init(&dev->lock);
> +	spin_lock_init(&dev->msg_lock);
> +	INIT_LIST_HEAD(&dev->send_list);
> +	INIT_LIST_HEAD(&dev->recv_list);
> +	spin_lock_init(&dev->irq_lock);
> +
> +	INIT_WORK(&dev->inject, vduse_dev_irq_inject);
> +	init_waitqueue_head(&dev->waitq);
> +
> +	return dev;
> +}
> +
> +static void vduse_dev_destroy(struct vduse_dev *dev)
> +{
> +	kfree(dev);
> +}
> +
> +static struct vduse_dev *vduse_find_dev(const char *name)
> +{
> +	struct vduse_dev *dev;
> +	int id;
> +
> +	idr_for_each_entry(&vduse_idr, dev, id)
> +		if (!strcmp(dev->name, name))
> +			return dev;
> +
> +	return NULL;
> +}
> +
> +static int vduse_destroy_dev(char *name)
> +{
> +	struct vduse_dev *dev = vduse_find_dev(name);
> +
> +	if (!dev)
> +		return -EINVAL;
> +
> +	mutex_lock(&dev->lock);
> +	if (dev->vdev || dev->connected) {
> +		mutex_unlock(&dev->lock);
> +		return -EBUSY;
> +	}
> +	dev->connected = true;
> +	mutex_unlock(&dev->lock);
> +
> +	vduse_dev_msg_cleanup(dev);
> +	device_destroy(vduse_class, MKDEV(MAJOR(vduse_major), dev->minor));
> +	idr_remove(&vduse_idr, dev->minor);
> +	kvfree(dev->config);
> +	kfree(dev->vqs);
> +	vduse_domain_destroy(dev->domain);
> +	kfree(dev->name);
> +	vduse_dev_destroy(dev);
> +	module_put(THIS_MODULE);
> +
> +	return 0;
> +}
> +
> +static bool device_is_allowed(u32 device_id)
> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(allowed_device_id); i++)
> +		if (allowed_device_id[i] == device_id)
> +			return true;
> +
> +	return false;
> +}
> +
> +static bool features_is_valid(u64 features)
> +{
> +	if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))
> +		return false;
> +
> +	/* Now we only support read-only configuration space */
> +	if (features & (1ULL << VIRTIO_BLK_F_CONFIG_WCE))
> +		return false;
> +
> +	return true;
> +}
> +
> +static bool vduse_validate_config(struct vduse_dev_config *config)
> +{
> +	if (config->bounce_size > VDUSE_MAX_BOUNCE_SIZE)
> +		return false;
> +
> +	if (config->vq_align > PAGE_SIZE)
> +		return false;
> +
> +	if (config->config_size > PAGE_SIZE)
> +		return false;
> +
> +	if (!device_is_allowed(config->device_id))
> +		return false;
> +
> +	if (!features_is_valid(config->features))
> +		return false;


Do we need to validate whether or not config_size is too small otherwise 
we may have OOB access in get_config()?


> +
> +	return true;
> +}
> +
> +static int vduse_create_dev(struct vduse_dev_config *config,
> +			    void *config_buf, u64 api_version)
> +{
> +	int i, ret;
> +	struct vduse_dev *dev;
> +
> +	ret = -EEXIST;
> +	if (vduse_find_dev(config->name))
> +		goto err;
> +
> +	ret = -ENOMEM;
> +	dev = vduse_dev_create();
> +	if (!dev)
> +		goto err;
> +
> +	dev->api_version = api_version;
> +	dev->user_features = config->features;
> +	dev->device_id = config->device_id;
> +	dev->vendor_id = config->vendor_id;
> +	dev->name = kstrdup(config->name, GFP_KERNEL);
> +	if (!dev->name)
> +		goto err_str;
> +
> +	dev->domain = vduse_domain_create(VDUSE_IOVA_SIZE - 1,
> +					  config->bounce_size);
> +	if (!dev->domain)
> +		goto err_domain;
> +
> +	dev->config = config_buf;
> +	dev->config_size = config->config_size;
> +	dev->vq_align = config->vq_align;
> +	dev->vq_size_max = config->vq_size_max;
> +	dev->vq_num = config->vq_num;
> +	dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), GFP_KERNEL);
> +	if (!dev->vqs)
> +		goto err_vqs;
> +
> +	for (i = 0; i < dev->vq_num; i++) {
> +		dev->vqs[i].index = i;
> +		INIT_WORK(&dev->vqs[i].inject, vduse_vq_irq_inject);
> +		spin_lock_init(&dev->vqs[i].kick_lock);
> +		spin_lock_init(&dev->vqs[i].irq_lock);
> +	}
> +
> +	ret = idr_alloc(&vduse_idr, dev, 1, VDUSE_DEV_MAX, GFP_KERNEL);
> +	if (ret < 0)
> +		goto err_idr;
> +
> +	dev->minor = ret;
> +	dev->dev = device_create(vduse_class, NULL,
> +				 MKDEV(MAJOR(vduse_major), dev->minor),
> +				 NULL, "%s", config->name);
> +	if (IS_ERR(dev->dev)) {
> +		ret = PTR_ERR(dev->dev);
> +		goto err_dev;
> +	}
> +	__module_get(THIS_MODULE);
> +
> +	return 0;
> +err_dev:
> +	idr_remove(&vduse_idr, dev->minor);
> +err_idr:
> +	kfree(dev->vqs);
> +err_vqs:
> +	vduse_domain_destroy(dev->domain);
> +err_domain:
> +	kfree(dev->name);
> +err_str:
> +	vduse_dev_destroy(dev);
> +err:
> +	kvfree(config_buf);
> +	return ret;
> +}
> +
> +static long vduse_ioctl(struct file *file, unsigned int cmd,
> +			unsigned long arg)
> +{
> +	int ret;
> +	void __user *argp = (void __user *)arg;
> +	struct vduse_control *control = file->private_data;
> +
> +	mutex_lock(&vduse_lock);
> +	switch (cmd) {
> +	case VDUSE_GET_API_VERSION:
> +		ret = put_user(control->api_version, (u64 __user *)argp);
> +		break;
> +	case VDUSE_SET_API_VERSION: {
> +		u64 api_version;
> +
> +		ret = -EFAULT;
> +		if (get_user(api_version, (u64 __user *)argp))
> +			break;
> +
> +		ret = -EINVAL;
> +		if (api_version > VDUSE_API_VERSION)
> +			break;
> +
> +		ret = 0;
> +		control->api_version = api_version;
> +		break;
> +	}
> +	case VDUSE_CREATE_DEV: {
> +		struct vduse_dev_config config;
> +		unsigned long size = offsetof(struct vduse_dev_config, config);
> +		void *buf;
> +
> +		ret = -EFAULT;
> +		if (copy_from_user(&config, argp, size))
> +			break;
> +
> +		ret = -EINVAL;
> +		if (vduse_validate_config(&config) == false)
> +			break;
> +
> +		buf = vmemdup_user(argp + size, config.config_size);
> +		if (IS_ERR(buf)) {
> +			ret = PTR_ERR(buf);
> +			break;
> +		}
> +		ret = vduse_create_dev(&config, buf, control->api_version);
> +		break;
> +	}
> +	case VDUSE_DESTROY_DEV: {
> +		char name[VDUSE_NAME_MAX];
> +
> +		ret = -EFAULT;
> +		if (copy_from_user(name, argp, VDUSE_NAME_MAX))
> +			break;
> +
> +		ret = vduse_destroy_dev(name);
> +		break;
> +	}
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +	mutex_unlock(&vduse_lock);
> +
> +	return ret;
> +}
> +
> +static int vduse_release(struct inode *inode, struct file *file)
> +{
> +	struct vduse_control *control = file->private_data;
> +
> +	kfree(control);
> +	return 0;
> +}
> +
> +static int vduse_open(struct inode *inode, struct file *file)
> +{
> +	struct vduse_control *control;
> +
> +	control = kmalloc(sizeof(struct vduse_control), GFP_KERNEL);
> +	if (!control)
> +		return -ENOMEM;
> +
> +	control->api_version = VDUSE_API_VERSION;
> +	file->private_data = control;
> +
> +	return 0;
> +}
> +
> +static const struct file_operations vduse_ctrl_fops = {
> +	.owner		= THIS_MODULE,
> +	.open		= vduse_open,
> +	.release	= vduse_release,
> +	.unlocked_ioctl	= vduse_ioctl,
> +	.compat_ioctl	= compat_ptr_ioctl,
> +	.llseek		= noop_llseek,
> +};
> +
> +static char *vduse_devnode(struct device *dev, umode_t *mode)
> +{
> +	return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));
> +}
> +
> +static void vduse_mgmtdev_release(struct device *dev)
> +{
> +}
> +
> +static struct device vduse_mgmtdev = {
> +	.init_name = "vduse",
> +	.release = vduse_mgmtdev_release,
> +};
> +
> +static struct vdpa_mgmt_dev mgmt_dev;
> +
> +static int vduse_dev_init_vdpa(struct vduse_dev *dev, const char *name)
> +{
> +	struct vduse_vdpa *vdev;
> +	int ret;
> +
> +	if (dev->vdev)
> +		return -EEXIST;
> +
> +	vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, dev->dev,
> +				 &vduse_vdpa_config_ops, name, true);
> +	if (!vdev)
> +		return -ENOMEM;
> +
> +	dev->vdev = vdev;
> +	vdev->dev = dev;
> +	vdev->vdpa.dev.dma_mask = &vdev->vdpa.dev.coherent_dma_mask;
> +	ret = dma_set_mask_and_coherent(&vdev->vdpa.dev, DMA_BIT_MASK(64));
> +	if (ret) {
> +		put_device(&vdev->vdpa.dev);
> +		return ret;
> +	}
> +	set_dma_ops(&vdev->vdpa.dev, &vduse_dev_dma_ops);
> +	vdev->vdpa.dma_dev = &vdev->vdpa.dev;
> +	vdev->vdpa.mdev = &mgmt_dev;
> +
> +	return 0;
> +}
> +
> +static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)
> +{
> +	struct vduse_dev *dev;
> +	int ret;
> +
> +	mutex_lock(&vduse_lock);
> +	dev = vduse_find_dev(name);
> +	if (!dev) {
> +		mutex_unlock(&vduse_lock);
> +		return -EINVAL;
> +	}
> +	ret = vduse_dev_init_vdpa(dev, name);
> +	mutex_unlock(&vduse_lock);
> +	if (ret)
> +		return ret;
> +
> +	ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);
> +	if (ret) {
> +		put_device(&dev->vdev->vdpa.dev);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void vdpa_dev_del(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev)
> +{
> +	_vdpa_unregister_device(dev);
> +}
> +
> +static const struct vdpa_mgmtdev_ops vdpa_dev_mgmtdev_ops = {
> +	.dev_add = vdpa_dev_add,
> +	.dev_del = vdpa_dev_del,
> +};
> +
> +static struct virtio_device_id id_table[] = {
> +	{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
> +	{ 0 },
> +};
> +
> +static struct vdpa_mgmt_dev mgmt_dev = {
> +	.device = &vduse_mgmtdev,
> +	.id_table = id_table,
> +	.ops = &vdpa_dev_mgmtdev_ops,
> +};
> +
> +static int vduse_mgmtdev_init(void)
> +{
> +	int ret;
> +
> +	ret = device_register(&vduse_mgmtdev);
> +	if (ret)
> +		return ret;
> +
> +	ret = vdpa_mgmtdev_register(&mgmt_dev);
> +	if (ret)
> +		goto err;
> +
> +	return 0;
> +err:
> +	device_unregister(&vduse_mgmtdev);
> +	return ret;
> +}
> +
> +static void vduse_mgmtdev_exit(void)
> +{
> +	vdpa_mgmtdev_unregister(&mgmt_dev);
> +	device_unregister(&vduse_mgmtdev);
> +}
> +
> +static int vduse_init(void)
> +{
> +	int ret;
> +	struct device *dev;
> +
> +	vduse_class = class_create(THIS_MODULE, "vduse");
> +	if (IS_ERR(vduse_class))
> +		return PTR_ERR(vduse_class);
> +
> +	vduse_class->devnode = vduse_devnode;
> +
> +	ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse");
> +	if (ret)
> +		goto err_chardev_region;
> +
> +	/* /dev/vduse/control */
> +	cdev_init(&vduse_ctrl_cdev, &vduse_ctrl_fops);
> +	vduse_ctrl_cdev.owner = THIS_MODULE;
> +	ret = cdev_add(&vduse_ctrl_cdev, vduse_major, 1);
> +	if (ret)
> +		goto err_ctrl_cdev;
> +
> +	dev = device_create(vduse_class, NULL, vduse_major, NULL, "control");
> +	if (IS_ERR(dev)) {
> +		ret = PTR_ERR(dev);
> +		goto err_device;
> +	}
> +
> +	/* /dev/vduse/$DEVICE */
> +	cdev_init(&vduse_cdev, &vduse_dev_fops);
> +	vduse_cdev.owner = THIS_MODULE;
> +	ret = cdev_add(&vduse_cdev, MKDEV(MAJOR(vduse_major), 1),
> +		       VDUSE_DEV_MAX - 1);
> +	if (ret)
> +		goto err_cdev;
> +
> +	vduse_irq_wq = alloc_workqueue("vduse-irq",
> +				WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);
> +	if (!vduse_irq_wq)
> +		goto err_wq;
> +
> +	ret = vduse_domain_init();
> +	if (ret)
> +		goto err_domain;
> +
> +	ret = vduse_mgmtdev_init();
> +	if (ret)
> +		goto err_mgmtdev;
> +
> +	return 0;
> +err_mgmtdev:
> +	vduse_domain_exit();
> +err_domain:
> +	destroy_workqueue(vduse_irq_wq);
> +err_wq:
> +	cdev_del(&vduse_cdev);
> +err_cdev:
> +	device_destroy(vduse_class, vduse_major);
> +err_device:
> +	cdev_del(&vduse_ctrl_cdev);
> +err_ctrl_cdev:
> +	unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
> +err_chardev_region:
> +	class_destroy(vduse_class);
> +	return ret;
> +}
> +module_init(vduse_init);
> +
> +static void vduse_exit(void)
> +{
> +	vduse_mgmtdev_exit();
> +	vduse_domain_exit();
> +	destroy_workqueue(vduse_irq_wq);
> +	cdev_del(&vduse_cdev);
> +	device_destroy(vduse_class, vduse_major);
> +	cdev_del(&vduse_ctrl_cdev);
> +	unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
> +	class_destroy(vduse_class);
> +}
> +module_exit(vduse_exit);
> +
> +MODULE_LICENSE(DRV_LICENSE);
> +MODULE_AUTHOR(DRV_AUTHOR);
> +MODULE_DESCRIPTION(DRV_DESC);
> diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> new file mode 100644
> index 000000000000..f21b2e51b5c8
> --- /dev/null
> +++ b/include/uapi/linux/vduse.h
> @@ -0,0 +1,143 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +#ifndef _UAPI_VDUSE_H_
> +#define _UAPI_VDUSE_H_
> +
> +#include <linux/types.h>
> +
> +#define VDUSE_API_VERSION	0
> +
> +#define VDUSE_NAME_MAX	256
> +
> +/* the control messages definition for read/write */
> +
> +enum vduse_req_type {
> +	/* Get the state for virtqueue from userspace */
> +	VDUSE_GET_VQ_STATE,
> +	/* Notify userspace to start the dataplane, no reply */
> +	VDUSE_START_DATAPLANE,
> +	/* Notify userspace to stop the dataplane, no reply */
> +	VDUSE_STOP_DATAPLANE,
> +	/* Notify userspace to update the memory mapping in device IOTLB */
> +	VDUSE_UPDATE_IOTLB,
> +};
> +
> +struct vduse_vq_state {
> +	__u32 index; /* virtqueue index */
> +	__u32 avail_idx; /* virtqueue state (last_avail_idx) */
> +};


This needs some tweaks to support packed virtqueue.


> +
> +struct vduse_iova_range {
> +	__u64 start; /* start of the IOVA range */
> +	__u64 last; /* end of the IOVA range */
> +};
> +
> +struct vduse_dev_request {
> +	__u32 type; /* request type */
> +	__u32 request_id; /* request id */
> +#define VDUSE_REQ_FLAGS_NO_REPLY	(1 << 0) /* No need to reply */
> +	__u32 flags; /* request flags */
> +	__u32 reserved; /* for future use */
> +	union {
> +		struct vduse_vq_state vq_state; /* virtqueue state */
> +		struct vduse_iova_range iova; /* iova range for updating */
> +		__u32 padding[16]; /* padding */
> +	};
> +};
> +
> +struct vduse_dev_response {
> +	__u32 request_id; /* corresponding request id */
> +#define VDUSE_REQ_RESULT_OK	0x00
> +#define VDUSE_REQ_RESULT_FAILED	0x01
> +	__u32 result; /* the result of request */
> +	__u32 reserved[2]; /* for future use */
> +	union {
> +		struct vduse_vq_state vq_state; /* virtqueue state */
> +		__u32 padding[16]; /* padding */
> +	};
> +};
> +
> +/* ioctls */
> +
> +struct vduse_dev_config {
> +	char name[VDUSE_NAME_MAX]; /* vduse device name */
> +	__u32 vendor_id; /* virtio vendor id */
> +	__u32 device_id; /* virtio device id */
> +	__u64 features; /* device features */
> +	__u64 bounce_size; /* bounce buffer size for iommu */
> +	__u16 vq_size_max; /* the max size of virtqueue */
> +	__u16 padding; /* padding */
> +	__u32 vq_num; /* the number of virtqueues */
> +	__u32 vq_align; /* the allocation alignment of virtqueue's metadata */
> +	__u32 config_size; /* the size of the configuration space */
> +	__u32 reserved[15]; /* for future use */
> +	__u8 config[0]; /* the buffer of the configuration space */
> +};
> +
> +struct vduse_iotlb_entry {
> +	__u64 offset; /* the mmap offset on fd */
> +	__u64 start; /* start of the IOVA range */
> +	__u64 last; /* last of the IOVA range */
> +#define VDUSE_ACCESS_RO 0x1
> +#define VDUSE_ACCESS_WO 0x2
> +#define VDUSE_ACCESS_RW 0x3
> +	__u8 perm; /* access permission of this range */
> +};
> +
> +struct vduse_config_update {
> +	__u32 offset; /* offset from the beginning of configuration space */
> +	__u32 length; /* the length to write to configuration space */
> +	__u8 buffer[0]; /* buffer used to write from */
> +};
> +
> +struct vduse_vq_info {
> +	__u32 index; /* virtqueue index */
> +	__u32 avail_idx; /* virtqueue state (last_avail_idx) */
> +	__u64 desc_addr; /* address of desc area */
> +	__u64 driver_addr; /* address of driver area */
> +	__u64 device_addr; /* address of device area */
> +	__u32 num; /* the size of virtqueue */
> +	__u8 ready; /* ready status of virtqueue */
> +};
> +
> +struct vduse_vq_eventfd {
> +	__u32 index; /* virtqueue index */
> +#define VDUSE_EVENTFD_DEASSIGN -1
> +	int fd; /* eventfd, -1 means de-assigning the eventfd */
> +};
> +
> +#define VDUSE_BASE	0x81
> +
> +/* Get the version of VDUSE API. This is used for future extension */
> +#define VDUSE_GET_API_VERSION	_IOR(VDUSE_BASE, 0x00, __u64)
> +
> +/* Set the version of VDUSE API. */
> +#define VDUSE_SET_API_VERSION	_IOW(VDUSE_BASE, 0x01, __u64)
> +
> +/* Create a vduse device which is represented by a char device (/dev/vduse/<name>) */
> +#define VDUSE_CREATE_DEV	_IOW(VDUSE_BASE, 0x02, struct vduse_dev_config)
> +
> +/* Destroy a vduse device. Make sure there are no references to the char device */
> +#define VDUSE_DESTROY_DEV	_IOW(VDUSE_BASE, 0x03, char[VDUSE_NAME_MAX])
> +
> +/*
> + * Get a file descriptor for the first overlapped iova region,
> + * -EINVAL means the iova region doesn't exist.
> + */
> +#define VDUSE_IOTLB_GET_FD	_IOWR(VDUSE_BASE, 0x04, struct vduse_iotlb_entry)
> +
> +/* Get the negotiated features */
> +#define VDUSE_DEV_GET_FEATURES	_IOR(VDUSE_BASE, 0x05, __u64)
> +
> +/* Update the configuration space */
> +#define VDUSE_DEV_UPDATE_CONFIG	_IOW(VDUSE_BASE, 0x06, struct vduse_config_update)
> +
> +/* Get the specified virtqueue's information */
> +#define VDUSE_VQ_GET_INFO	_IOWR(VDUSE_BASE, 0x07, struct vduse_vq_info)
> +
> +/* Setup an eventfd to receive kick for virtqueue */
> +#define VDUSE_VQ_SETUP_KICKFD	_IOW(VDUSE_BASE, 0x08, struct vduse_vq_eventfd)
> +
> +/* Inject an interrupt for specific virtqueue */
> +#define VDUSE_VQ_INJECT_IRQ	_IOW(VDUSE_BASE, 0x09, __u32)
> +
> +#endif /* _UAPI_VDUSE_H_ */

Yongji Xie June 21, 2021, 10:41 a.m. UTC | #2

On Mon, Jun 21, 2021 at 5:14 PM Jason Wang <[e-mail]> wrote:
>
>
> 在 2021/6/15 下午10:13, Xie Yongji 写道:
> > This VDUSE driver enables implementing vDPA devices in userspace.
> > The vDPA device's control path is handled in kernel and the data
> > path is handled in userspace.
> >
> > A message mechnism is used by VDUSE driver to forward some control
> > messages such as starting/stopping datapath to userspace. Userspace
> > can use read()/write() to receive/reply those control messages.
> >
> > And some ioctls are introduced to help userspace to implement the
> > data path. VDUSE_IOTLB_GET_FD ioctl can be used to get the file
> > descriptors referring to vDPA device's iova regions. Then userspace
> > can use mmap() to access those iova regions. VDUSE_DEV_GET_FEATURES
> > and VDUSE_VQ_GET_INFO ioctls are used to get the negotiated features
> > and metadata of virtqueues. VDUSE_INJECT_VQ_IRQ and VDUSE_VQ_SETUP_KICKFD
> > ioctls can be used to inject interrupt and setup the kickfd for
> > virtqueues. VDUSE_DEV_UPDATE_CONFIG ioctl is used to update the
> > configuration space and inject a config interrupt.
> >
> > Signed-off-by: Xie Yongji <[e-mail]>
> > ---
> >   Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +
> >   drivers/vdpa/Kconfig                               |   10 +
> >   drivers/vdpa/Makefile                              |    1 +
> >   drivers/vdpa/vdpa_user/Makefile                    |    5 +
> >   drivers/vdpa/vdpa_user/vduse_dev.c                 | 1453 ++++++++++++++++++++
> >   include/uapi/linux/vduse.h                         |  143 ++
> >   6 files changed, 1613 insertions(+)
> >   create mode 100644 drivers/vdpa/vdpa_user/Makefile
> >   create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c
> >   create mode 100644 include/uapi/linux/vduse.h
> >
> > diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> > index 9bfc2b510c64..acd95e9dcfe7 100644
> > --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> > +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> > @@ -300,6 +300,7 @@ Code  Seq#    Include File                                           Comments
> >   'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                        conflict!
> >   '|'   00-7F  linux/media.h
> >   0x80  00-1F  linux/fb.h
> > +0x81  00-1F  linux/vduse.h
> >   0x89  00-06  arch/x86/include/asm/sockios.h
> >   0x89  0B-DF  linux/sockios.h
> >   0x89  E0-EF  linux/sockios.h                                         SIOCPROTOPRIVATE range
> > diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
> > index a503c1b2bfd9..6e23bce6433a 100644
> > --- a/drivers/vdpa/Kconfig
> > +++ b/drivers/vdpa/Kconfig
> > @@ -33,6 +33,16 @@ config VDPA_SIM_BLOCK
> >         vDPA block device simulator which terminates IO request in a
> >         memory buffer.
> >
> > +config VDPA_USER
> > +     tristate "VDUSE (vDPA Device in Userspace) support"
> > +     depends on EVENTFD && MMU && HAS_DMA
> > +     select DMA_OPS
> > +     select VHOST_IOTLB
> > +     select IOMMU_IOVA
> > +     help
> > +       With VDUSE it is possible to emulate a vDPA Device
> > +       in a userspace program.
> > +
> >   config IFCVF
> >       tristate "Intel IFC VF vDPA driver"
> >       depends on PCI_MSI
> > diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile
> > index 67fe7f3d6943..f02ebed33f19 100644
> > --- a/drivers/vdpa/Makefile
> > +++ b/drivers/vdpa/Makefile
> > @@ -1,6 +1,7 @@
> >   # SPDX-License-Identifier: GPL-2.0
> >   obj-$(CONFIG_VDPA) += vdpa.o
> >   obj-$(CONFIG_VDPA_SIM) += vdpa_sim/
> > +obj-$(CONFIG_VDPA_USER) += vdpa_user/
> >   obj-$(CONFIG_IFCVF)    += ifcvf/
> >   obj-$(CONFIG_MLX5_VDPA) += mlx5/
> >   obj-$(CONFIG_VP_VDPA)    += virtio_pci/
> > diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile
> > new file mode 100644
> > index 000000000000..260e0b26af99
> > --- /dev/null
> > +++ b/drivers/vdpa/vdpa_user/Makefile
> > @@ -0,0 +1,5 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +
> > +vduse-y := vduse_dev.o iova_domain.o
> > +
> > +obj-$(CONFIG_VDPA_USER) += vduse.o
> > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> > new file mode 100644
> > index 000000000000..5271cbd15e28
> > --- /dev/null
> > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> > @@ -0,0 +1,1453 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * VDUSE: vDPA Device in Userspace
> > + *
> > + * Copyright (C) 2020-2021 Bytedance Inc. and/or its affiliates. All rights reserved.
> > + *
> > + * Author: Xie Yongji <[e-mail]>
> > + *
> > + */
> > +
> > +#include <linux/init.h>
> > +#include <linux/module.h>
> > +#include <linux/cdev.h>
> > +#include <linux/device.h>
> > +#include <linux/eventfd.h>
> > +#include <linux/slab.h>
> > +#include <linux/wait.h>
> > +#include <linux/dma-map-ops.h>
> > +#include <linux/poll.h>
> > +#include <linux/file.h>
> > +#include <linux/uio.h>
> > +#include <linux/vdpa.h>
> > +#include <linux/nospec.h>
> > +#include <uapi/linux/vduse.h>
> > +#include <uapi/linux/vdpa.h>
> > +#include <uapi/linux/virtio_config.h>
> > +#include <uapi/linux/virtio_ids.h>
> > +#include <uapi/linux/virtio_blk.h>
> > +#include <linux/mod_devicetable.h>
> > +
> > +#include "iova_domain.h"
> > +
> > +#define DRV_AUTHOR   "Yongji Xie <[e-mail]>"
> > +#define DRV_DESC     "vDPA Device in Userspace"
> > +#define DRV_LICENSE  "GPL v2"
> > +
> > +#define VDUSE_DEV_MAX (1U << MINORBITS)
> > +#define VDUSE_MAX_BOUNCE_SIZE (64 * 1024 * 1024)
> > +#define VDUSE_IOVA_SIZE (128 * 1024 * 1024)
> > +#define VDUSE_REQUEST_TIMEOUT 30
> > +
> > +struct vduse_virtqueue {
> > +     u16 index;
> > +     u32 num;
> > +     u32 avail_idx;
> > +     u64 desc_addr;
> > +     u64 driver_addr;
> > +     u64 device_addr;
> > +     bool ready;
> > +     bool kicked;
> > +     spinlock_t kick_lock;
> > +     spinlock_t irq_lock;
> > +     struct eventfd_ctx *kickfd;
> > +     struct vdpa_callback cb;
> > +     struct work_struct inject;
> > +};
> > +
> > +struct vduse_dev;
> > +
> > +struct vduse_vdpa {
> > +     struct vdpa_device vdpa;
> > +     struct vduse_dev *dev;
> > +};
> > +
> > +struct vduse_dev {
> > +     struct vduse_vdpa *vdev;
> > +     struct device *dev;
> > +     struct vduse_virtqueue *vqs;
> > +     struct vduse_iova_domain *domain;
> > +     char *name;
> > +     struct mutex lock;
> > +     spinlock_t msg_lock;
> > +     u64 msg_unique;
> > +     wait_queue_head_t waitq;
> > +     struct list_head send_list;
> > +     struct list_head recv_list;
> > +     struct vdpa_callback config_cb;
> > +     struct work_struct inject;
> > +     spinlock_t irq_lock;
> > +     int minor;
> > +     bool connected;
> > +     bool started;
> > +     u64 api_version;
> > +     u64 user_features;
>
>
> Let's use device_features.
>

OK.

>
> > +     u64 features;
>
>
> And driver features.
>

OK.

>
> > +     u32 device_id;
> > +     u32 vendor_id;
> > +     u32 generation;
> > +     u32 config_size;
> > +     void *config;
> > +     u8 status;
> > +     u16 vq_size_max;
> > +     u32 vq_num;
> > +     u32 vq_align;
> > +};
> > +
> > +struct vduse_dev_msg {
> > +     struct vduse_dev_request req;
> > +     struct vduse_dev_response resp;
> > +     struct list_head list;
> > +     wait_queue_head_t waitq;
> > +     bool completed;
> > +};
> > +
> > +struct vduse_control {
> > +     u64 api_version;
> > +};
> > +
> > +static DEFINE_MUTEX(vduse_lock);
> > +static DEFINE_IDR(vduse_idr);
> > +
> > +static dev_t vduse_major;
> > +static struct class *vduse_class;
> > +static struct cdev vduse_ctrl_cdev;
> > +static struct cdev vduse_cdev;
> > +static struct workqueue_struct *vduse_irq_wq;
> > +
> > +static u32 allowed_device_id[] = {
> > +     VIRTIO_ID_BLOCK,
> > +};
> > +
> > +static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa)
> > +{
> > +     struct vduse_vdpa *vdev = container_of(vdpa, struct vduse_vdpa, vdpa);
> > +
> > +     return vdev->dev;
> > +}
> > +
> > +static inline struct vduse_dev *dev_to_vduse(struct device *dev)
> > +{
> > +     struct vdpa_device *vdpa = dev_to_vdpa(dev);
> > +
> > +     return vdpa_to_vduse(vdpa);
> > +}
> > +
> > +static struct vduse_dev_msg *vduse_find_msg(struct list_head *head,
> > +                                         uint32_t request_id)
> > +{
> > +     struct vduse_dev_msg *msg;
> > +
> > +     list_for_each_entry(msg, head, list) {
> > +             if (msg->req.request_id == request_id) {
> > +                     list_del(&msg->list);
> > +                     return msg;
> > +             }
> > +     }
> > +
> > +     return NULL;
> > +}
> > +
> > +static struct vduse_dev_msg *vduse_dequeue_msg(struct list_head *head)
> > +{
> > +     struct vduse_dev_msg *msg = NULL;
> > +
> > +     if (!list_empty(head)) {
> > +             msg = list_first_entry(head, struct vduse_dev_msg, list);
> > +             list_del(&msg->list);
> > +     }
> > +
> > +     return msg;
> > +}
> > +
> > +static void vduse_enqueue_msg(struct list_head *head,
> > +                           struct vduse_dev_msg *msg)
> > +{
> > +     list_add_tail(&msg->list, head);
> > +}
> > +
> > +static int vduse_dev_msg_send(struct vduse_dev *dev,
> > +                           struct vduse_dev_msg *msg, bool no_reply)
> > +{
>
>
> It looks to me the only user for no_reply=true is the dataplane start. I
> wonder no_reply is really needed consider we have switched to use
> wait_event_killable_timeout().
>

Do we need to handle the error in this case if we remove the no_reply
flag. Print a warning message?

> In another way, no_reply is false for vq state synchronization and IOTLB
> updating. I wonder if we can simply use no_reply = true for them.
>

Looks like we can't, e.g. we need to get a reply from userspace for vq state.

>
> > +     init_waitqueue_head(&msg->waitq);
> > +     spin_lock(&dev->msg_lock);
> > +     msg->req.request_id = dev->msg_unique++;
> > +     vduse_enqueue_msg(&dev->send_list, msg);
> > +     wake_up(&dev->waitq);
> > +     spin_unlock(&dev->msg_lock);
> > +     if (no_reply)
> > +             return 0;
> > +
> > +     wait_event_killable_timeout(msg->waitq, msg->completed,
> > +                                 VDUSE_REQUEST_TIMEOUT * HZ);
> > +     spin_lock(&dev->msg_lock);
> > +     if (!msg->completed) {
> > +             list_del(&msg->list);
> > +             msg->resp.result = VDUSE_REQ_RESULT_FAILED;
> > +     }
> > +     spin_unlock(&dev->msg_lock);
> > +
> > +     return (msg->resp.result == VDUSE_REQ_RESULT_OK) ? 0 : -EIO;
>
>
> Do we need to serialize the check by protecting it with the spinlock above?
>

Good point.

>
> > +}
> > +
> > +static void vduse_dev_msg_cleanup(struct vduse_dev *dev)
> > +{
> > +     struct vduse_dev_msg *msg;
> > +
> > +     spin_lock(&dev->msg_lock);
> > +     while ((msg = vduse_dequeue_msg(&dev->send_list))) {
> > +             if (msg->req.flags & VDUSE_REQ_FLAGS_NO_REPLY)
> > +                     kfree(msg);
> > +             else
> > +                     vduse_enqueue_msg(&dev->recv_list, msg);
> > +     }
> > +     while ((msg = vduse_dequeue_msg(&dev->recv_list))) {
> > +             msg->resp.result = VDUSE_REQ_RESULT_FAILED;
> > +             msg->completed = 1;
> > +             wake_up(&msg->waitq);
> > +     }
> > +     spin_unlock(&dev->msg_lock);
> > +}
> > +
> > +static void vduse_dev_start_dataplane(struct vduse_dev *dev)
> > +{
> > +     struct vduse_dev_msg *msg = kzalloc(sizeof(*msg),
> > +                                         GFP_KERNEL | __GFP_NOFAIL);
> > +
> > +     msg->req.type = VDUSE_START_DATAPLANE;
> > +     msg->req.flags |= VDUSE_REQ_FLAGS_NO_REPLY;
> > +     vduse_dev_msg_send(dev, msg, true);
> > +}
> > +
> > +static void vduse_dev_stop_dataplane(struct vduse_dev *dev)
> > +{
> > +     struct vduse_dev_msg *msg = kzalloc(sizeof(*msg),
> > +                                         GFP_KERNEL | __GFP_NOFAIL);
> > +
> > +     msg->req.type = VDUSE_STOP_DATAPLANE;
> > +     msg->req.flags |= VDUSE_REQ_FLAGS_NO_REPLY;
>
>
> Can we simply use this flag instead of introducing a new parameter
> (no_reply) in vduse_dev_msg_send()?
>

Looks good to me.

>
> > +     vduse_dev_msg_send(dev, msg, true);
> > +}
> > +
> > +static int vduse_dev_get_vq_state(struct vduse_dev *dev,
> > +                               struct vduse_virtqueue *vq,
> > +                               struct vdpa_vq_state *state)
> > +{
> > +     struct vduse_dev_msg msg = { 0 };
> > +     int ret;
>
>
> Note that I post a series that implement the packed virtqueue support:
>
> https://lists.linuxfoundation.org/pipermail/virtualization/2021-June/054501.html
>
> So this patch needs to be updated as well.
>

Will do it.

>
> > +
> > +     msg.req.type = VDUSE_GET_VQ_STATE;
> > +     msg.req.vq_state.index = vq->index;
> > +
> > +     ret = vduse_dev_msg_send(dev, &msg, false);
> > +     if (ret)
> > +             return ret;
> > +
> > +     state->avail_index = msg.resp.vq_state.avail_idx;
> > +     return 0;
> > +}
> > +
> > +static int vduse_dev_update_iotlb(struct vduse_dev *dev,
> > +                             u64 start, u64 last)
> > +{
> > +     struct vduse_dev_msg msg = { 0 };
> > +
> > +     if (last < start)
> > +             return -EINVAL;
> > +
> > +     msg.req.type = VDUSE_UPDATE_IOTLB;
> > +     msg.req.iova.start = start;
> > +     msg.req.iova.last = last;
> > +
> > +     return vduse_dev_msg_send(dev, &msg, false);
> > +}
> > +
> > +static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to)
> > +{
> > +     struct file *file = iocb->ki_filp;
> > +     struct vduse_dev *dev = file->private_data;
> > +     struct vduse_dev_msg *msg;
> > +     int size = sizeof(struct vduse_dev_request);
> > +     ssize_t ret;
> > +
> > +     if (iov_iter_count(to) < size)
> > +             return -EINVAL;
> > +
> > +     spin_lock(&dev->msg_lock);
> > +     while (1) {
> > +             msg = vduse_dequeue_msg(&dev->send_list);
> > +             if (msg)
> > +                     break;
> > +
> > +             ret = -EAGAIN;
> > +             if (file->f_flags & O_NONBLOCK)
> > +                     goto unlock;
> > +
> > +             spin_unlock(&dev->msg_lock);
> > +             ret = wait_event_interruptible_exclusive(dev->waitq,
> > +                                     !list_empty(&dev->send_list));
> > +             if (ret)
> > +                     return ret;
> > +
> > +             spin_lock(&dev->msg_lock);
> > +     }
> > +     spin_unlock(&dev->msg_lock);
> > +     ret = copy_to_iter(&msg->req, size, to);
> > +     spin_lock(&dev->msg_lock);
> > +     if (ret != size) {
> > +             ret = -EFAULT;
> > +             vduse_enqueue_msg(&dev->send_list, msg);
> > +             goto unlock;
> > +     }
> > +     if (msg->req.flags & VDUSE_REQ_FLAGS_NO_REPLY)
> > +             kfree(msg);
> > +     else
> > +             vduse_enqueue_msg(&dev->recv_list, msg);
> > +unlock:
> > +     spin_unlock(&dev->msg_lock);
> > +
> > +     return ret;
> > +}
> > +
> > +static ssize_t vduse_dev_write_iter(struct kiocb *iocb, struct iov_iter *from)
> > +{
> > +     struct file *file = iocb->ki_filp;
> > +     struct vduse_dev *dev = file->private_data;
> > +     struct vduse_dev_response resp;
> > +     struct vduse_dev_msg *msg;
> > +     size_t ret;
> > +
> > +     ret = copy_from_iter(&resp, sizeof(resp), from);
> > +     if (ret != sizeof(resp))
> > +             return -EINVAL;
> > +
> > +     spin_lock(&dev->msg_lock);
> > +     msg = vduse_find_msg(&dev->recv_list, resp.request_id);
> > +     if (!msg) {
> > +             ret = -ENOENT;
> > +             goto unlock;
> > +     }
> > +
> > +     memcpy(&msg->resp, &resp, sizeof(resp));
> > +     msg->completed = 1;
> > +     wake_up(&msg->waitq);
> > +unlock:
> > +     spin_unlock(&dev->msg_lock);
> > +
> > +     return ret;
> > +}
> > +
> > +static __poll_t vduse_dev_poll(struct file *file, poll_table *wait)
> > +{
> > +     struct vduse_dev *dev = file->private_data;
> > +     __poll_t mask = 0;
> > +
> > +     poll_wait(file, &dev->waitq, wait);
> > +
> > +     if (!list_empty(&dev->send_list))
> > +             mask |= EPOLLIN | EPOLLRDNORM;
> > +     if (!list_empty(&dev->recv_list))
> > +             mask |= EPOLLOUT | EPOLLWRNORM;
> > +
> > +     return mask;
> > +}
> > +
> > +static void vduse_dev_reset(struct vduse_dev *dev)
> > +{
> > +     int i;
> > +     struct vduse_iova_domain *domain = dev->domain;
> > +
> > +     /* The coherent mappings are handled in vduse_dev_free_coherent() */
> > +     if (domain->bounce_map)
> > +             vduse_domain_reset_bounce_map(domain);
> > +
> > +     dev->features = 0;
> > +     dev->generation++;
> > +     spin_lock(&dev->irq_lock);
> > +     dev->config_cb.callback = NULL;
> > +     dev->config_cb.private = NULL;
> > +     spin_unlock(&dev->irq_lock);
> > +
> > +     for (i = 0; i < dev->vq_num; i++) {
> > +             struct vduse_virtqueue *vq = &dev->vqs[i];
> > +
> > +             vq->ready = false;
> > +             vq->desc_addr = 0;
> > +             vq->driver_addr = 0;
> > +             vq->device_addr = 0;
> > +             vq->avail_idx = 0;
> > +             vq->num = 0;
> > +
> > +             spin_lock(&vq->kick_lock);
> > +             vq->kicked = false;
> > +             if (vq->kickfd)
> > +                     eventfd_ctx_put(vq->kickfd);
> > +             vq->kickfd = NULL;
> > +             spin_unlock(&vq->kick_lock);
> > +
> > +             spin_lock(&vq->irq_lock);
> > +             vq->cb.callback = NULL;
> > +             vq->cb.private = NULL;
> > +             spin_unlock(&vq->irq_lock);
> > +     }
> > +}
> > +
> > +static int vduse_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 idx,
> > +                             u64 desc_area, u64 driver_area,
> > +                             u64 device_area)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > +     vq->desc_addr = desc_area;
> > +     vq->driver_addr = driver_area;
> > +     vq->device_addr = device_area;
> > +
> > +     return 0;
> > +}
> > +
> > +static void vduse_vdpa_kick_vq(struct vdpa_device *vdpa, u16 idx)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > +     spin_lock(&vq->kick_lock);
> > +     if (!vq->ready)
> > +             goto unlock;
> > +
> > +     if (vq->kickfd)
> > +             eventfd_signal(vq->kickfd, 1);
> > +     else
> > +             vq->kicked = true;
> > +unlock:
> > +     spin_unlock(&vq->kick_lock);
> > +}
> > +
> > +static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,
> > +                           struct vdpa_callback *cb)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > +     spin_lock(&vq->irq_lock);
> > +     vq->cb.callback = cb->callback;
> > +     vq->cb.private = cb->private;
> > +     spin_unlock(&vq->irq_lock);
> > +}
> > +
> > +static void vduse_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > +     vq->num = num;
> > +}
> > +
> > +static void vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa,
> > +                                     u16 idx, bool ready)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > +     vq->ready = ready;
> > +}
> > +
> > +static bool vduse_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 idx)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > +     return vq->ready;
> > +}
> > +
> > +static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,
> > +                             const struct vdpa_vq_state *state)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > +     vq->avail_idx = state->avail_index;
> > +     return 0;
> > +}
> > +
> > +static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
> > +                             struct vdpa_vq_state *state)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > +     return vduse_dev_get_vq_state(dev, vq, state);
> > +}
> > +
> > +static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     return dev->vq_align;
> > +}
> > +
> > +static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     return dev->user_features;
> > +}
> > +
> > +static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     dev->features = features;
> > +     return 0;
> > +}
> > +
> > +static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,
> > +                               struct vdpa_callback *cb)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     spin_lock(&dev->irq_lock);
> > +     dev->config_cb.callback = cb->callback;
> > +     dev->config_cb.private = cb->private;
> > +     spin_unlock(&dev->irq_lock);
> > +}
> > +
> > +static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     return dev->vq_size_max;
> > +}
> > +
> > +static u32 vduse_vdpa_get_device_id(struct vdpa_device *vdpa)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     return dev->device_id;
> > +}
> > +
> > +static u32 vduse_vdpa_get_vendor_id(struct vdpa_device *vdpa)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     return dev->vendor_id;
> > +}
> > +
> > +static u8 vduse_vdpa_get_status(struct vdpa_device *vdpa)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     return dev->status;
> > +}
> > +
> > +static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +     bool started = !!(status & VIRTIO_CONFIG_S_DRIVER_OK);
> > +
> > +     dev->status = status;
> > +
> > +     if (dev->started == started)
> > +             return;
>
>
> If we check dev->status == status, (or only check the DRIVER_OK bit)
> then there's no need to introduce an extra dev->started.
>

Will do it.

>
> > +
> > +     dev->started = started;
> > +     if (dev->started) {
> > +             vduse_dev_start_dataplane(dev);
> > +     } else {
> > +             vduse_dev_reset(dev);
> > +             vduse_dev_stop_dataplane(dev);
>
>
> I wonder if no_reply work for the case of vhost-vdpa. For virtio-vDPA,
> we have bouncing buffers so it's harmless if usersapce dataplane keeps
> performing read/write. For vhost-vDPA we don't have such stuffs.
>

OK. So it still needs to be synchronized here. If so, how to handle
the error? Looks like printing a warning message should be enough.

>
> > +     }
> > +}
> > +
> > +static size_t vduse_vdpa_get_config_size(struct vdpa_device *vdpa)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     return dev->config_size;
> > +}
> > +
> > +static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,
> > +                               void *buf, unsigned int len)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     memcpy(buf, dev->config + offset, len);
> > +}
> > +
> > +static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,
> > +                     const void *buf, unsigned int len)
> > +{
> > +     /* Now we only support read-only configuration space */
> > +}
> > +
> > +static u32 vduse_vdpa_get_generation(struct vdpa_device *vdpa)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     return dev->generation;
> > +}
> > +
> > +static int vduse_vdpa_set_map(struct vdpa_device *vdpa,
> > +                             struct vhost_iotlb *iotlb)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +     int ret;
> > +
> > +     ret = vduse_domain_set_map(dev->domain, iotlb);
> > +     if (ret)
> > +             return ret;
> > +
> > +     ret = vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
> > +     if (ret) {
> > +             vduse_domain_clear_map(dev->domain, iotlb);
> > +             return ret;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static void vduse_vdpa_free(struct vdpa_device *vdpa)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     dev->vdev = NULL;
> > +}
> > +
> > +static const struct vdpa_config_ops vduse_vdpa_config_ops = {
> > +     .set_vq_address         = vduse_vdpa_set_vq_address,
> > +     .kick_vq                = vduse_vdpa_kick_vq,
> > +     .set_vq_cb              = vduse_vdpa_set_vq_cb,
> > +     .set_vq_num             = vduse_vdpa_set_vq_num,
> > +     .set_vq_ready           = vduse_vdpa_set_vq_ready,
> > +     .get_vq_ready           = vduse_vdpa_get_vq_ready,
> > +     .set_vq_state           = vduse_vdpa_set_vq_state,
> > +     .get_vq_state           = vduse_vdpa_get_vq_state,
> > +     .get_vq_align           = vduse_vdpa_get_vq_align,
> > +     .get_features           = vduse_vdpa_get_features,
> > +     .set_features           = vduse_vdpa_set_features,
> > +     .set_config_cb          = vduse_vdpa_set_config_cb,
> > +     .get_vq_num_max         = vduse_vdpa_get_vq_num_max,
> > +     .get_device_id          = vduse_vdpa_get_device_id,
> > +     .get_vendor_id          = vduse_vdpa_get_vendor_id,
> > +     .get_status             = vduse_vdpa_get_status,
> > +     .set_status             = vduse_vdpa_set_status,
> > +     .get_config_size        = vduse_vdpa_get_config_size,
> > +     .get_config             = vduse_vdpa_get_config,
> > +     .set_config             = vduse_vdpa_set_config,
> > +     .get_generation         = vduse_vdpa_get_generation,
> > +     .set_map                = vduse_vdpa_set_map,
> > +     .free                   = vduse_vdpa_free,
> > +};
> > +
> > +static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,
> > +                                  unsigned long offset, size_t size,
> > +                                  enum dma_data_direction dir,
> > +                                  unsigned long attrs)
> > +{
> > +     struct vduse_dev *vdev = dev_to_vduse(dev);
> > +     struct vduse_iova_domain *domain = vdev->domain;
> > +
> > +     return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
> > +}
> > +
> > +static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,
> > +                             size_t size, enum dma_data_direction dir,
> > +                             unsigned long attrs)
> > +{
> > +     struct vduse_dev *vdev = dev_to_vduse(dev);
> > +     struct vduse_iova_domain *domain = vdev->domain;
> > +
> > +     return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
> > +}
> > +
> > +static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,
> > +                                     dma_addr_t *dma_addr, gfp_t flag,
> > +                                     unsigned long attrs)
> > +{
> > +     struct vduse_dev *vdev = dev_to_vduse(dev);
> > +     struct vduse_iova_domain *domain = vdev->domain;
> > +     unsigned long iova;
> > +     void *addr;
> > +
> > +     *dma_addr = DMA_MAPPING_ERROR;
> > +     addr = vduse_domain_alloc_coherent(domain, size,
> > +                             (dma_addr_t *)&iova, flag, attrs);
> > +     if (!addr)
> > +             return NULL;
> > +
> > +     *dma_addr = (dma_addr_t)iova;
> > +
> > +     return addr;
> > +}
> > +
> > +static void vduse_dev_free_coherent(struct device *dev, size_t size,
> > +                                     void *vaddr, dma_addr_t dma_addr,
> > +                                     unsigned long attrs)
> > +{
> > +     struct vduse_dev *vdev = dev_to_vduse(dev);
> > +     struct vduse_iova_domain *domain = vdev->domain;
> > +
> > +     vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
> > +}
> > +
> > +static size_t vduse_dev_max_mapping_size(struct device *dev)
> > +{
> > +     struct vduse_dev *vdev = dev_to_vduse(dev);
> > +     struct vduse_iova_domain *domain = vdev->domain;
> > +
> > +     return domain->bounce_size;
> > +}
> > +
> > +static const struct dma_map_ops vduse_dev_dma_ops = {
> > +     .map_page = vduse_dev_map_page,
> > +     .unmap_page = vduse_dev_unmap_page,
> > +     .alloc = vduse_dev_alloc_coherent,
> > +     .free = vduse_dev_free_coherent,
> > +     .max_mapping_size = vduse_dev_max_mapping_size,
> > +};
> > +
> > +static unsigned int perm_to_file_flags(u8 perm)
> > +{
> > +     unsigned int flags = 0;
> > +
> > +     switch (perm) {
> > +     case VDUSE_ACCESS_WO:
> > +             flags |= O_WRONLY;
> > +             break;
> > +     case VDUSE_ACCESS_RO:
> > +             flags |= O_RDONLY;
> > +             break;
> > +     case VDUSE_ACCESS_RW:
> > +             flags |= O_RDWR;
> > +             break;
> > +     default:
> > +             WARN(1, "invalidate vhost IOTLB permission\n");
> > +             break;
> > +     }
> > +
> > +     return flags;
> > +}
> > +
> > +static int vduse_kickfd_setup(struct vduse_dev *dev,
> > +                     struct vduse_vq_eventfd *eventfd)
> > +{
> > +     struct eventfd_ctx *ctx = NULL;
> > +     struct vduse_virtqueue *vq;
> > +     u32 index;
> > +
> > +     if (eventfd->index >= dev->vq_num)
> > +             return -EINVAL;
> > +
> > +     index = array_index_nospec(eventfd->index, dev->vq_num);
> > +     vq = &dev->vqs[index];
> > +     if (eventfd->fd >= 0) {
> > +             ctx = eventfd_ctx_fdget(eventfd->fd);
> > +             if (IS_ERR(ctx))
> > +                     return PTR_ERR(ctx);
> > +     } else if (eventfd->fd != VDUSE_EVENTFD_DEASSIGN)
> > +             return 0;
> > +
> > +     spin_lock(&vq->kick_lock);
> > +     if (vq->kickfd)
> > +             eventfd_ctx_put(vq->kickfd);
> > +     vq->kickfd = ctx;
> > +     if (vq->ready && vq->kicked && vq->kickfd) {
> > +             eventfd_signal(vq->kickfd, 1);
> > +             vq->kicked = false;
> > +     }
> > +     spin_unlock(&vq->kick_lock);
> > +
> > +     return 0;
> > +}
> > +
> > +static void vduse_dev_irq_inject(struct work_struct *work)
> > +{
> > +     struct vduse_dev *dev = container_of(work, struct vduse_dev, inject);
> > +
> > +     spin_lock_irq(&dev->irq_lock);
> > +     if (dev->config_cb.callback)
> > +             dev->config_cb.callback(dev->config_cb.private);
> > +     spin_unlock_irq(&dev->irq_lock);
> > +}
> > +
> > +static void vduse_vq_irq_inject(struct work_struct *work)
> > +{
> > +     struct vduse_virtqueue *vq = container_of(work,
> > +                                     struct vduse_virtqueue, inject);
> > +
> > +     spin_lock_irq(&vq->irq_lock);
> > +     if (vq->ready && vq->cb.callback)
> > +             vq->cb.callback(vq->cb.private);
> > +     spin_unlock_irq(&vq->irq_lock);
> > +}
> > +
> > +static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
> > +                         unsigned long arg)
> > +{
> > +     struct vduse_dev *dev = file->private_data;
> > +     void __user *argp = (void __user *)arg;
> > +     int ret;
> > +
> > +     switch (cmd) {
> > +     case VDUSE_IOTLB_GET_FD: {
> > +             struct vduse_iotlb_entry entry;
> > +             struct vhost_iotlb_map *map;
> > +             struct vdpa_map_file *map_file;
> > +             struct vduse_iova_domain *domain = dev->domain;
> > +             struct file *f = NULL;
> > +
> > +             ret = -EFAULT;
> > +             if (copy_from_user(&entry, argp, sizeof(entry)))
> > +                     break;
> > +
> > +             ret = -EINVAL;
> > +             if (entry.start > entry.last)
> > +                     break;
> > +
> > +             spin_lock(&domain->iotlb_lock);
> > +             map = vhost_iotlb_itree_first(domain->iotlb,
> > +                                           entry.start, entry.last);
> > +             if (map) {
> > +                     map_file = (struct vdpa_map_file *)map->opaque;
> > +                     f = get_file(map_file->file);
> > +                     entry.offset = map_file->offset;
> > +                     entry.start = map->start;
> > +                     entry.last = map->last;
> > +                     entry.perm = map->perm;
> > +             }
> > +             spin_unlock(&domain->iotlb_lock);
> > +             ret = -EINVAL;
> > +             if (!f)
> > +                     break;
> > +
> > +             ret = -EFAULT;
> > +             if (copy_to_user(argp, &entry, sizeof(entry))) {
> > +                     fput(f);
> > +                     break;
> > +             }
> > +             ret = receive_fd(f, perm_to_file_flags(entry.perm));
> > +             fput(f);
> > +             break;
> > +     }
> > +     case VDUSE_DEV_GET_FEATURES:
> > +             ret = put_user(dev->features, (u64 __user *)argp);
> > +             break;
> > +     case VDUSE_DEV_UPDATE_CONFIG: {
> > +             struct vduse_config_update config;
> > +             unsigned long size = offsetof(struct vduse_config_update,
> > +                                           buffer);
> > +
> > +             ret = -EFAULT;
> > +             if (copy_from_user(&config, argp, size))
> > +                     break;
> > +
> > +             ret = -EINVAL;
> > +             if (config.length == 0 ||
> > +                 config.length > dev->config_size - config.offset)
> > +                     break;
> > +
> > +             ret = -EFAULT;
> > +             if (copy_from_user(dev->config + config.offset, argp + size,
> > +                                config.length))
> > +                     break;
> > +
> > +             ret = 0;
> > +             queue_work(vduse_irq_wq, &dev->inject);
>
>
> I wonder if it's better to separate config interrupt out of config
> update or we need document this.
>

I have documented it in the docs. Looks like a config update should be
always followed by a config interrupt. I didn't find a case that uses
them separately.

>
> > +             break;
> > +     }
> > +     case VDUSE_VQ_GET_INFO: {
>
>
> Do we need to limit this only when DRIVER_OK is set?
>

Any reason to add this limitation?

>
> > +             struct vduse_vq_info vq_info;
> > +             u32 vq_index;
> > +
> > +             ret = -EFAULT;
> > +             if (copy_from_user(&vq_info, argp, sizeof(vq_info)))
> > +                     break;
> > +
> > +             ret = -EINVAL;
> > +             if (vq_info.index >= dev->vq_num)
> > +                     break;
> > +
> > +             vq_index = array_index_nospec(vq_info.index, dev->vq_num);
> > +             vq_info.desc_addr = dev->vqs[vq_index].desc_addr;
> > +             vq_info.driver_addr = dev->vqs[vq_index].driver_addr;
> > +             vq_info.device_addr = dev->vqs[vq_index].device_addr;
> > +             vq_info.num = dev->vqs[vq_index].num;
> > +             vq_info.avail_idx = dev->vqs[vq_index].avail_idx;
> > +             vq_info.ready = dev->vqs[vq_index].ready;
> > +
> > +             ret = -EFAULT;
> > +             if (copy_to_user(argp, &vq_info, sizeof(vq_info)))
> > +                     break;
> > +
> > +             ret = 0;
> > +             break;
> > +     }
> > +     case VDUSE_VQ_SETUP_KICKFD: {
> > +             struct vduse_vq_eventfd eventfd;
> > +
> > +             ret = -EFAULT;
> > +             if (copy_from_user(&eventfd, argp, sizeof(eventfd)))
> > +                     break;
> > +
> > +             ret = vduse_kickfd_setup(dev, &eventfd);
> > +             break;
> > +     }
> > +     case VDUSE_VQ_INJECT_IRQ: {
> > +             u32 vq_index;
> > +
> > +             ret = -EFAULT;
> > +             if (get_user(vq_index, (u32 __user *)argp))
> > +                     break;
> > +
> > +             ret = -EINVAL;
> > +             if (vq_index >= dev->vq_num)
> > +                     break;
> > +
> > +             ret = 0;
> > +             vq_index = array_index_nospec(vq_index, dev->vq_num);
> > +             queue_work(vduse_irq_wq, &dev->vqs[vq_index].inject);
> > +             break;
> > +     }
> > +     default:
> > +             ret = -ENOIOCTLCMD;
> > +             break;
> > +     }
> > +
> > +     return ret;
> > +}
> > +
> > +static int vduse_dev_release(struct inode *inode, struct file *file)
> > +{
> > +     struct vduse_dev *dev = file->private_data;
> > +
> > +     spin_lock(&dev->msg_lock);
> > +     /* Make sure the inflight messages can processed after reconncection */
> > +     list_splice_init(&dev->recv_list, &dev->send_list);
> > +     spin_unlock(&dev->msg_lock);
> > +     dev->connected = false;
> > +
> > +     return 0;
> > +}
> > +
> > +static struct vduse_dev *vduse_dev_get_from_minor(int minor)
> > +{
> > +     struct vduse_dev *dev;
> > +
> > +     mutex_lock(&vduse_lock);
> > +     dev = idr_find(&vduse_idr, minor);
> > +     mutex_unlock(&vduse_lock);
> > +
> > +     return dev;
> > +}
> > +
> > +static int vduse_dev_open(struct inode *inode, struct file *file)
> > +{
> > +     int ret;
> > +     struct vduse_dev *dev = vduse_dev_get_from_minor(iminor(inode));
> > +
> > +     if (!dev)
> > +             return -ENODEV;
> > +
> > +     ret = -EBUSY;
> > +     mutex_lock(&dev->lock);
> > +     if (dev->connected)
> > +             goto unlock;
> > +
> > +     ret = 0;
> > +     dev->connected = true;
> > +     file->private_data = dev;
> > +unlock:
> > +     mutex_unlock(&dev->lock);
> > +
> > +     return ret;
> > +}
> > +
> > +static const struct file_operations vduse_dev_fops = {
> > +     .owner          = THIS_MODULE,
> > +     .open           = vduse_dev_open,
> > +     .release        = vduse_dev_release,
> > +     .read_iter      = vduse_dev_read_iter,
> > +     .write_iter     = vduse_dev_write_iter,
> > +     .poll           = vduse_dev_poll,
> > +     .unlocked_ioctl = vduse_dev_ioctl,
> > +     .compat_ioctl   = compat_ptr_ioctl,
> > +     .llseek         = noop_llseek,
> > +};
> > +
> > +static struct vduse_dev *vduse_dev_create(void)
> > +{
> > +     struct vduse_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> > +
> > +     if (!dev)
> > +             return NULL;
> > +
> > +     mutex_init(&dev->lock);
> > +     spin_lock_init(&dev->msg_lock);
> > +     INIT_LIST_HEAD(&dev->send_list);
> > +     INIT_LIST_HEAD(&dev->recv_list);
> > +     spin_lock_init(&dev->irq_lock);
> > +
> > +     INIT_WORK(&dev->inject, vduse_dev_irq_inject);
> > +     init_waitqueue_head(&dev->waitq);
> > +
> > +     return dev;
> > +}
> > +
> > +static void vduse_dev_destroy(struct vduse_dev *dev)
> > +{
> > +     kfree(dev);
> > +}
> > +
> > +static struct vduse_dev *vduse_find_dev(const char *name)
> > +{
> > +     struct vduse_dev *dev;
> > +     int id;
> > +
> > +     idr_for_each_entry(&vduse_idr, dev, id)
> > +             if (!strcmp(dev->name, name))
> > +                     return dev;
> > +
> > +     return NULL;
> > +}
> > +
> > +static int vduse_destroy_dev(char *name)
> > +{
> > +     struct vduse_dev *dev = vduse_find_dev(name);
> > +
> > +     if (!dev)
> > +             return -EINVAL;
> > +
> > +     mutex_lock(&dev->lock);
> > +     if (dev->vdev || dev->connected) {
> > +             mutex_unlock(&dev->lock);
> > +             return -EBUSY;
> > +     }
> > +     dev->connected = true;
> > +     mutex_unlock(&dev->lock);
> > +
> > +     vduse_dev_msg_cleanup(dev);
> > +     device_destroy(vduse_class, MKDEV(MAJOR(vduse_major), dev->minor));
> > +     idr_remove(&vduse_idr, dev->minor);
> > +     kvfree(dev->config);
> > +     kfree(dev->vqs);
> > +     vduse_domain_destroy(dev->domain);
> > +     kfree(dev->name);
> > +     vduse_dev_destroy(dev);
> > +     module_put(THIS_MODULE);
> > +
> > +     return 0;
> > +}
> > +
> > +static bool device_is_allowed(u32 device_id)
> > +{
> > +     int i;
> > +
> > +     for (i = 0; i < ARRAY_SIZE(allowed_device_id); i++)
> > +             if (allowed_device_id[i] == device_id)
> > +                     return true;
> > +
> > +     return false;
> > +}
> > +
> > +static bool features_is_valid(u64 features)
> > +{
> > +     if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))
> > +             return false;
> > +
> > +     /* Now we only support read-only configuration space */
> > +     if (features & (1ULL << VIRTIO_BLK_F_CONFIG_WCE))
> > +             return false;
> > +
> > +     return true;
> > +}
> > +
> > +static bool vduse_validate_config(struct vduse_dev_config *config)
> > +{
> > +     if (config->bounce_size > VDUSE_MAX_BOUNCE_SIZE)
> > +             return false;
> > +
> > +     if (config->vq_align > PAGE_SIZE)
> > +             return false;
> > +
> > +     if (config->config_size > PAGE_SIZE)
> > +             return false;
> > +
> > +     if (!device_is_allowed(config->device_id))
> > +             return false;
> > +
> > +     if (!features_is_valid(config->features))
> > +             return false;
>
>
> Do we need to validate whether or not config_size is too small otherwise
> we may have OOB access in get_config()?
>

How about adding validation in get_config()? It seems to be hard to
define the lower bound.

>
> > +
> > +     return true;
> > +}
> > +
> > +static int vduse_create_dev(struct vduse_dev_config *config,
> > +                         void *config_buf, u64 api_version)
> > +{
> > +     int i, ret;
> > +     struct vduse_dev *dev;
> > +
> > +     ret = -EEXIST;
> > +     if (vduse_find_dev(config->name))
> > +             goto err;
> > +
> > +     ret = -ENOMEM;
> > +     dev = vduse_dev_create();
> > +     if (!dev)
> > +             goto err;
> > +
> > +     dev->api_version = api_version;
> > +     dev->user_features = config->features;
> > +     dev->device_id = config->device_id;
> > +     dev->vendor_id = config->vendor_id;
> > +     dev->name = kstrdup(config->name, GFP_KERNEL);
> > +     if (!dev->name)
> > +             goto err_str;
> > +
> > +     dev->domain = vduse_domain_create(VDUSE_IOVA_SIZE - 1,
> > +                                       config->bounce_size);
> > +     if (!dev->domain)
> > +             goto err_domain;
> > +
> > +     dev->config = config_buf;
> > +     dev->config_size = config->config_size;
> > +     dev->vq_align = config->vq_align;
> > +     dev->vq_size_max = config->vq_size_max;
> > +     dev->vq_num = config->vq_num;
> > +     dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), GFP_KERNEL);
> > +     if (!dev->vqs)
> > +             goto err_vqs;
> > +
> > +     for (i = 0; i < dev->vq_num; i++) {
> > +             dev->vqs[i].index = i;
> > +             INIT_WORK(&dev->vqs[i].inject, vduse_vq_irq_inject);
> > +             spin_lock_init(&dev->vqs[i].kick_lock);
> > +             spin_lock_init(&dev->vqs[i].irq_lock);
> > +     }
> > +
> > +     ret = idr_alloc(&vduse_idr, dev, 1, VDUSE_DEV_MAX, GFP_KERNEL);
> > +     if (ret < 0)
> > +             goto err_idr;
> > +
> > +     dev->minor = ret;
> > +     dev->dev = device_create(vduse_class, NULL,
> > +                              MKDEV(MAJOR(vduse_major), dev->minor),
> > +                              NULL, "%s", config->name);
> > +     if (IS_ERR(dev->dev)) {
> > +             ret = PTR_ERR(dev->dev);
> > +             goto err_dev;
> > +     }
> > +     __module_get(THIS_MODULE);
> > +
> > +     return 0;
> > +err_dev:
> > +     idr_remove(&vduse_idr, dev->minor);
> > +err_idr:
> > +     kfree(dev->vqs);
> > +err_vqs:
> > +     vduse_domain_destroy(dev->domain);
> > +err_domain:
> > +     kfree(dev->name);
> > +err_str:
> > +     vduse_dev_destroy(dev);
> > +err:
> > +     kvfree(config_buf);
> > +     return ret;
> > +}
> > +
> > +static long vduse_ioctl(struct file *file, unsigned int cmd,
> > +                     unsigned long arg)
> > +{
> > +     int ret;
> > +     void __user *argp = (void __user *)arg;
> > +     struct vduse_control *control = file->private_data;
> > +
> > +     mutex_lock(&vduse_lock);
> > +     switch (cmd) {
> > +     case VDUSE_GET_API_VERSION:
> > +             ret = put_user(control->api_version, (u64 __user *)argp);
> > +             break;
> > +     case VDUSE_SET_API_VERSION: {
> > +             u64 api_version;
> > +
> > +             ret = -EFAULT;
> > +             if (get_user(api_version, (u64 __user *)argp))
> > +                     break;
> > +
> > +             ret = -EINVAL;
> > +             if (api_version > VDUSE_API_VERSION)
> > +                     break;
> > +
> > +             ret = 0;
> > +             control->api_version = api_version;
> > +             break;
> > +     }
> > +     case VDUSE_CREATE_DEV: {
> > +             struct vduse_dev_config config;
> > +             unsigned long size = offsetof(struct vduse_dev_config, config);
> > +             void *buf;
> > +
> > +             ret = -EFAULT;
> > +             if (copy_from_user(&config, argp, size))
> > +                     break;
> > +
> > +             ret = -EINVAL;
> > +             if (vduse_validate_config(&config) == false)
> > +                     break;
> > +
> > +             buf = vmemdup_user(argp + size, config.config_size);
> > +             if (IS_ERR(buf)) {
> > +                     ret = PTR_ERR(buf);
> > +                     break;
> > +             }
> > +             ret = vduse_create_dev(&config, buf, control->api_version);
> > +             break;
> > +     }
> > +     case VDUSE_DESTROY_DEV: {
> > +             char name[VDUSE_NAME_MAX];
> > +
> > +             ret = -EFAULT;
> > +             if (copy_from_user(name, argp, VDUSE_NAME_MAX))
> > +                     break;
> > +
> > +             ret = vduse_destroy_dev(name);
> > +             break;
> > +     }
> > +     default:
> > +             ret = -EINVAL;
> > +             break;
> > +     }
> > +     mutex_unlock(&vduse_lock);
> > +
> > +     return ret;
> > +}
> > +
> > +static int vduse_release(struct inode *inode, struct file *file)
> > +{
> > +     struct vduse_control *control = file->private_data;
> > +
> > +     kfree(control);
> > +     return 0;
> > +}
> > +
> > +static int vduse_open(struct inode *inode, struct file *file)
> > +{
> > +     struct vduse_control *control;
> > +
> > +     control = kmalloc(sizeof(struct vduse_control), GFP_KERNEL);
> > +     if (!control)
> > +             return -ENOMEM;
> > +
> > +     control->api_version = VDUSE_API_VERSION;
> > +     file->private_data = control;
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct file_operations vduse_ctrl_fops = {
> > +     .owner          = THIS_MODULE,
> > +     .open           = vduse_open,
> > +     .release        = vduse_release,
> > +     .unlocked_ioctl = vduse_ioctl,
> > +     .compat_ioctl   = compat_ptr_ioctl,
> > +     .llseek         = noop_llseek,
> > +};
> > +
> > +static char *vduse_devnode(struct device *dev, umode_t *mode)
> > +{
> > +     return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));
> > +}
> > +
> > +static void vduse_mgmtdev_release(struct device *dev)
> > +{
> > +}
> > +
> > +static struct device vduse_mgmtdev = {
> > +     .init_name = "vduse",
> > +     .release = vduse_mgmtdev_release,
> > +};
> > +
> > +static struct vdpa_mgmt_dev mgmt_dev;
> > +
> > +static int vduse_dev_init_vdpa(struct vduse_dev *dev, const char *name)
> > +{
> > +     struct vduse_vdpa *vdev;
> > +     int ret;
> > +
> > +     if (dev->vdev)
> > +             return -EEXIST;
> > +
> > +     vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, dev->dev,
> > +                              &vduse_vdpa_config_ops, name, true);
> > +     if (!vdev)
> > +             return -ENOMEM;
> > +
> > +     dev->vdev = vdev;
> > +     vdev->dev = dev;
> > +     vdev->vdpa.dev.dma_mask = &vdev->vdpa.dev.coherent_dma_mask;
> > +     ret = dma_set_mask_and_coherent(&vdev->vdpa.dev, DMA_BIT_MASK(64));
> > +     if (ret) {
> > +             put_device(&vdev->vdpa.dev);
> > +             return ret;
> > +     }
> > +     set_dma_ops(&vdev->vdpa.dev, &vduse_dev_dma_ops);
> > +     vdev->vdpa.dma_dev = &vdev->vdpa.dev;
> > +     vdev->vdpa.mdev = &mgmt_dev;
> > +
> > +     return 0;
> > +}
> > +
> > +static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)
> > +{
> > +     struct vduse_dev *dev;
> > +     int ret;
> > +
> > +     mutex_lock(&vduse_lock);
> > +     dev = vduse_find_dev(name);
> > +     if (!dev) {
> > +             mutex_unlock(&vduse_lock);
> > +             return -EINVAL;
> > +     }
> > +     ret = vduse_dev_init_vdpa(dev, name);
> > +     mutex_unlock(&vduse_lock);
> > +     if (ret)
> > +             return ret;
> > +
> > +     ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);
> > +     if (ret) {
> > +             put_device(&dev->vdev->vdpa.dev);
> > +             return ret;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static void vdpa_dev_del(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev)
> > +{
> > +     _vdpa_unregister_device(dev);
> > +}
> > +
> > +static const struct vdpa_mgmtdev_ops vdpa_dev_mgmtdev_ops = {
> > +     .dev_add = vdpa_dev_add,
> > +     .dev_del = vdpa_dev_del,
> > +};
> > +
> > +static struct virtio_device_id id_table[] = {
> > +     { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
> > +     { 0 },
> > +};
> > +
> > +static struct vdpa_mgmt_dev mgmt_dev = {
> > +     .device = &vduse_mgmtdev,
> > +     .id_table = id_table,
> > +     .ops = &vdpa_dev_mgmtdev_ops,
> > +};
> > +
> > +static int vduse_mgmtdev_init(void)
> > +{
> > +     int ret;
> > +
> > +     ret = device_register(&vduse_mgmtdev);
> > +     if (ret)
> > +             return ret;
> > +
> > +     ret = vdpa_mgmtdev_register(&mgmt_dev);
> > +     if (ret)
> > +             goto err;
> > +
> > +     return 0;
> > +err:
> > +     device_unregister(&vduse_mgmtdev);
> > +     return ret;
> > +}
> > +
> > +static void vduse_mgmtdev_exit(void)
> > +{
> > +     vdpa_mgmtdev_unregister(&mgmt_dev);
> > +     device_unregister(&vduse_mgmtdev);
> > +}
> > +
> > +static int vduse_init(void)
> > +{
> > +     int ret;
> > +     struct device *dev;
> > +
> > +     vduse_class = class_create(THIS_MODULE, "vduse");
> > +     if (IS_ERR(vduse_class))
> > +             return PTR_ERR(vduse_class);
> > +
> > +     vduse_class->devnode = vduse_devnode;
> > +
> > +     ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse");
> > +     if (ret)
> > +             goto err_chardev_region;
> > +
> > +     /* /dev/vduse/control */
> > +     cdev_init(&vduse_ctrl_cdev, &vduse_ctrl_fops);
> > +     vduse_ctrl_cdev.owner = THIS_MODULE;
> > +     ret = cdev_add(&vduse_ctrl_cdev, vduse_major, 1);
> > +     if (ret)
> > +             goto err_ctrl_cdev;
> > +
> > +     dev = device_create(vduse_class, NULL, vduse_major, NULL, "control");
> > +     if (IS_ERR(dev)) {
> > +             ret = PTR_ERR(dev);
> > +             goto err_device;
> > +     }
> > +
> > +     /* /dev/vduse/$DEVICE */
> > +     cdev_init(&vduse_cdev, &vduse_dev_fops);
> > +     vduse_cdev.owner = THIS_MODULE;
> > +     ret = cdev_add(&vduse_cdev, MKDEV(MAJOR(vduse_major), 1),
> > +                    VDUSE_DEV_MAX - 1);
> > +     if (ret)
> > +             goto err_cdev;
> > +
> > +     vduse_irq_wq = alloc_workqueue("vduse-irq",
> > +                             WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);
> > +     if (!vduse_irq_wq)
> > +             goto err_wq;
> > +
> > +     ret = vduse_domain_init();
> > +     if (ret)
> > +             goto err_domain;
> > +
> > +     ret = vduse_mgmtdev_init();
> > +     if (ret)
> > +             goto err_mgmtdev;
> > +
> > +     return 0;
> > +err_mgmtdev:
> > +     vduse_domain_exit();
> > +err_domain:
> > +     destroy_workqueue(vduse_irq_wq);
> > +err_wq:
> > +     cdev_del(&vduse_cdev);
> > +err_cdev:
> > +     device_destroy(vduse_class, vduse_major);
> > +err_device:
> > +     cdev_del(&vduse_ctrl_cdev);
> > +err_ctrl_cdev:
> > +     unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
> > +err_chardev_region:
> > +     class_destroy(vduse_class);
> > +     return ret;
> > +}
> > +module_init(vduse_init);
> > +
> > +static void vduse_exit(void)
> > +{
> > +     vduse_mgmtdev_exit();
> > +     vduse_domain_exit();
> > +     destroy_workqueue(vduse_irq_wq);
> > +     cdev_del(&vduse_cdev);
> > +     device_destroy(vduse_class, vduse_major);
> > +     cdev_del(&vduse_ctrl_cdev);
> > +     unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
> > +     class_destroy(vduse_class);
> > +}
> > +module_exit(vduse_exit);
> > +
> > +MODULE_LICENSE(DRV_LICENSE);
> > +MODULE_AUTHOR(DRV_AUTHOR);
> > +MODULE_DESCRIPTION(DRV_DESC);
> > diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> > new file mode 100644
> > index 000000000000..f21b2e51b5c8
> > --- /dev/null
> > +++ b/include/uapi/linux/vduse.h
> > @@ -0,0 +1,143 @@
> > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> > +#ifndef _UAPI_VDUSE_H_
> > +#define _UAPI_VDUSE_H_
> > +
> > +#include <linux/types.h>
> > +
> > +#define VDUSE_API_VERSION    0
> > +
> > +#define VDUSE_NAME_MAX       256
> > +
> > +/* the control messages definition for read/write */
> > +
> > +enum vduse_req_type {
> > +     /* Get the state for virtqueue from userspace */
> > +     VDUSE_GET_VQ_STATE,
> > +     /* Notify userspace to start the dataplane, no reply */
> > +     VDUSE_START_DATAPLANE,
> > +     /* Notify userspace to stop the dataplane, no reply */
> > +     VDUSE_STOP_DATAPLANE,
> > +     /* Notify userspace to update the memory mapping in device IOTLB */
> > +     VDUSE_UPDATE_IOTLB,
> > +};
> > +
> > +struct vduse_vq_state {
> > +     __u32 index; /* virtqueue index */
> > +     __u32 avail_idx; /* virtqueue state (last_avail_idx) */
> > +};
>
>
> This needs some tweaks to support packed virtqueue.
>

OK.

Thanks,
Yongji

Jason Wang June 22, 2021, 5:06 a.m. UTC | #3

在 2021/6/21 下午6:41, Yongji Xie 写道:
> On Mon, Jun 21, 2021 at 5:14 PM Jason Wang <[e-mail]> wrote:
>>
>> 在 2021/6/15 下午10:13, Xie Yongji 写道:
>>> This VDUSE driver enables implementing vDPA devices in userspace.
>>> The vDPA device's control path is handled in kernel and the data
>>> path is handled in userspace.
>>>
>>> A message mechnism is used by VDUSE driver to forward some control
>>> messages such as starting/stopping datapath to userspace. Userspace
>>> can use read()/write() to receive/reply those control messages.
>>>
>>> And some ioctls are introduced to help userspace to implement the
>>> data path. VDUSE_IOTLB_GET_FD ioctl can be used to get the file
>>> descriptors referring to vDPA device's iova regions. Then userspace
>>> can use mmap() to access those iova regions. VDUSE_DEV_GET_FEATURES
>>> and VDUSE_VQ_GET_INFO ioctls are used to get the negotiated features
>>> and metadata of virtqueues. VDUSE_INJECT_VQ_IRQ and VDUSE_VQ_SETUP_KICKFD
>>> ioctls can be used to inject interrupt and setup the kickfd for
>>> virtqueues. VDUSE_DEV_UPDATE_CONFIG ioctl is used to update the
>>> configuration space and inject a config interrupt.
>>>
>>> Signed-off-by: Xie Yongji <[e-mail]>
>>> ---
>>>    Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +
>>>    drivers/vdpa/Kconfig                               |   10 +
>>>    drivers/vdpa/Makefile                              |    1 +
>>>    drivers/vdpa/vdpa_user/Makefile                    |    5 +
>>>    drivers/vdpa/vdpa_user/vduse_dev.c                 | 1453 ++++++++++++++++++++
>>>    include/uapi/linux/vduse.h                         |  143 ++
>>>    6 files changed, 1613 insertions(+)
>>>    create mode 100644 drivers/vdpa/vdpa_user/Makefile
>>>    create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c
>>>    create mode 100644 include/uapi/linux/vduse.h
>>>
>>> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
>>> index 9bfc2b510c64..acd95e9dcfe7 100644
>>> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
>>> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
>>> @@ -300,6 +300,7 @@ Code  Seq#    Include File                                           Comments
>>>    'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                        conflict!
>>>    '|'   00-7F  linux/media.h
>>>    0x80  00-1F  linux/fb.h
>>> +0x81  00-1F  linux/vduse.h
>>>    0x89  00-06  arch/x86/include/asm/sockios.h
>>>    0x89  0B-DF  linux/sockios.h
>>>    0x89  E0-EF  linux/sockios.h                                         SIOCPROTOPRIVATE range
>>> diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
>>> index a503c1b2bfd9..6e23bce6433a 100644
>>> --- a/drivers/vdpa/Kconfig
>>> +++ b/drivers/vdpa/Kconfig
>>> @@ -33,6 +33,16 @@ config VDPA_SIM_BLOCK
>>>          vDPA block device simulator which terminates IO request in a
>>>          memory buffer.
>>>
>>> +config VDPA_USER
>>> +     tristate "VDUSE (vDPA Device in Userspace) support"
>>> +     depends on EVENTFD && MMU && HAS_DMA
>>> +     select DMA_OPS
>>> +     select VHOST_IOTLB
>>> +     select IOMMU_IOVA
>>> +     help
>>> +       With VDUSE it is possible to emulate a vDPA Device
>>> +       in a userspace program.
>>> +
>>>    config IFCVF
>>>        tristate "Intel IFC VF vDPA driver"
>>>        depends on PCI_MSI
>>> diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile
>>> index 67fe7f3d6943..f02ebed33f19 100644
>>> --- a/drivers/vdpa/Makefile
>>> +++ b/drivers/vdpa/Makefile
>>> @@ -1,6 +1,7 @@
>>>    # SPDX-License-Identifier: GPL-2.0
>>>    obj-$(CONFIG_VDPA) += vdpa.o
>>>    obj-$(CONFIG_VDPA_SIM) += vdpa_sim/
>>> +obj-$(CONFIG_VDPA_USER) += vdpa_user/
>>>    obj-$(CONFIG_IFCVF)    += ifcvf/
>>>    obj-$(CONFIG_MLX5_VDPA) += mlx5/
>>>    obj-$(CONFIG_VP_VDPA)    += virtio_pci/
>>> diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile
>>> new file mode 100644
>>> index 000000000000..260e0b26af99
>>> --- /dev/null
>>> +++ b/drivers/vdpa/vdpa_user/Makefile
>>> @@ -0,0 +1,5 @@
>>> +# SPDX-License-Identifier: GPL-2.0
>>> +
>>> +vduse-y := vduse_dev.o iova_domain.o
>>> +
>>> +obj-$(CONFIG_VDPA_USER) += vduse.o
>>> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
>>> new file mode 100644
>>> index 000000000000..5271cbd15e28
>>> --- /dev/null
>>> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
>>> @@ -0,0 +1,1453 @@
>>> +// SPDX-License-Identifier: GPL-2.0-only
>>> +/*
>>> + * VDUSE: vDPA Device in Userspace
>>> + *
>>> + * Copyright (C) 2020-2021 Bytedance Inc. and/or its affiliates. All rights reserved.
>>> + *
>>> + * Author: Xie Yongji <[e-mail]>
>>> + *
>>> + */
>>> +
>>> +#include <linux/init.h>
>>> +#include <linux/module.h>
>>> +#include <linux/cdev.h>
>>> +#include <linux/device.h>
>>> +#include <linux/eventfd.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/wait.h>
>>> +#include <linux/dma-map-ops.h>
>>> +#include <linux/poll.h>
>>> +#include <linux/file.h>
>>> +#include <linux/uio.h>
>>> +#include <linux/vdpa.h>
>>> +#include <linux/nospec.h>
>>> +#include <uapi/linux/vduse.h>
>>> +#include <uapi/linux/vdpa.h>
>>> +#include <uapi/linux/virtio_config.h>
>>> +#include <uapi/linux/virtio_ids.h>
>>> +#include <uapi/linux/virtio_blk.h>
>>> +#include <linux/mod_devicetable.h>
>>> +
>>> +#include "iova_domain.h"
>>> +
>>> +#define DRV_AUTHOR   "Yongji Xie <[e-mail]>"
>>> +#define DRV_DESC     "vDPA Device in Userspace"
>>> +#define DRV_LICENSE  "GPL v2"
>>> +
>>> +#define VDUSE_DEV_MAX (1U << MINORBITS)
>>> +#define VDUSE_MAX_BOUNCE_SIZE (64 * 1024 * 1024)
>>> +#define VDUSE_IOVA_SIZE (128 * 1024 * 1024)
>>> +#define VDUSE_REQUEST_TIMEOUT 30
>>> +
>>> +struct vduse_virtqueue {
>>> +     u16 index;
>>> +     u32 num;
>>> +     u32 avail_idx;
>>> +     u64 desc_addr;
>>> +     u64 driver_addr;
>>> +     u64 device_addr;
>>> +     bool ready;
>>> +     bool kicked;
>>> +     spinlock_t kick_lock;
>>> +     spinlock_t irq_lock;
>>> +     struct eventfd_ctx *kickfd;
>>> +     struct vdpa_callback cb;
>>> +     struct work_struct inject;
>>> +};
>>> +
>>> +struct vduse_dev;
>>> +
>>> +struct vduse_vdpa {
>>> +     struct vdpa_device vdpa;
>>> +     struct vduse_dev *dev;
>>> +};
>>> +
>>> +struct vduse_dev {
>>> +     struct vduse_vdpa *vdev;
>>> +     struct device *dev;
>>> +     struct vduse_virtqueue *vqs;
>>> +     struct vduse_iova_domain *domain;
>>> +     char *name;
>>> +     struct mutex lock;
>>> +     spinlock_t msg_lock;
>>> +     u64 msg_unique;
>>> +     wait_queue_head_t waitq;
>>> +     struct list_head send_list;
>>> +     struct list_head recv_list;
>>> +     struct vdpa_callback config_cb;
>>> +     struct work_struct inject;
>>> +     spinlock_t irq_lock;
>>> +     int minor;
>>> +     bool connected;
>>> +     bool started;
>>> +     u64 api_version;
>>> +     u64 user_features;
>>
>> Let's use device_features.
>>
> OK.
>
>>> +     u64 features;
>>
>> And driver features.
>>
> OK.
>
>>> +     u32 device_id;
>>> +     u32 vendor_id;
>>> +     u32 generation;
>>> +     u32 config_size;
>>> +     void *config;
>>> +     u8 status;
>>> +     u16 vq_size_max;
>>> +     u32 vq_num;
>>> +     u32 vq_align;
>>> +};
>>> +
>>> +struct vduse_dev_msg {
>>> +     struct vduse_dev_request req;
>>> +     struct vduse_dev_response resp;
>>> +     struct list_head list;
>>> +     wait_queue_head_t waitq;
>>> +     bool completed;
>>> +};
>>> +
>>> +struct vduse_control {
>>> +     u64 api_version;
>>> +};
>>> +
>>> +static DEFINE_MUTEX(vduse_lock);
>>> +static DEFINE_IDR(vduse_idr);
>>> +
>>> +static dev_t vduse_major;
>>> +static struct class *vduse_class;
>>> +static struct cdev vduse_ctrl_cdev;
>>> +static struct cdev vduse_cdev;
>>> +static struct workqueue_struct *vduse_irq_wq;
>>> +
>>> +static u32 allowed_device_id[] = {
>>> +     VIRTIO_ID_BLOCK,
>>> +};
>>> +
>>> +static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa)
>>> +{
>>> +     struct vduse_vdpa *vdev = container_of(vdpa, struct vduse_vdpa, vdpa);
>>> +
>>> +     return vdev->dev;
>>> +}
>>> +
>>> +static inline struct vduse_dev *dev_to_vduse(struct device *dev)
>>> +{
>>> +     struct vdpa_device *vdpa = dev_to_vdpa(dev);
>>> +
>>> +     return vdpa_to_vduse(vdpa);
>>> +}
>>> +
>>> +static struct vduse_dev_msg *vduse_find_msg(struct list_head *head,
>>> +                                         uint32_t request_id)
>>> +{
>>> +     struct vduse_dev_msg *msg;
>>> +
>>> +     list_for_each_entry(msg, head, list) {
>>> +             if (msg->req.request_id == request_id) {
>>> +                     list_del(&msg->list);
>>> +                     return msg;
>>> +             }
>>> +     }
>>> +
>>> +     return NULL;
>>> +}
>>> +
>>> +static struct vduse_dev_msg *vduse_dequeue_msg(struct list_head *head)
>>> +{
>>> +     struct vduse_dev_msg *msg = NULL;
>>> +
>>> +     if (!list_empty(head)) {
>>> +             msg = list_first_entry(head, struct vduse_dev_msg, list);
>>> +             list_del(&msg->list);
>>> +     }
>>> +
>>> +     return msg;
>>> +}
>>> +
>>> +static void vduse_enqueue_msg(struct list_head *head,
>>> +                           struct vduse_dev_msg *msg)
>>> +{
>>> +     list_add_tail(&msg->list, head);
>>> +}
>>> +
>>> +static int vduse_dev_msg_send(struct vduse_dev *dev,
>>> +                           struct vduse_dev_msg *msg, bool no_reply)
>>> +{
>>
>> It looks to me the only user for no_reply=true is the dataplane start. I
>> wonder no_reply is really needed consider we have switched to use
>> wait_event_killable_timeout().
>>
> Do we need to handle the error in this case if we remove the no_reply
> flag. Print a warning message?


See below.


>
>> In another way, no_reply is false for vq state synchronization and IOTLB
>> updating. I wonder if we can simply use no_reply = true for them.
>>
> Looks like we can't, e.g. we need to get a reply from userspace for vq state.


Right.


>
>>> +     init_waitqueue_head(&msg->waitq);
>>> +     spin_lock(&dev->msg_lock);
>>> +     msg->req.request_id = dev->msg_unique++;
>>> +     vduse_enqueue_msg(&dev->send_list, msg);
>>> +     wake_up(&dev->waitq);
>>> +     spin_unlock(&dev->msg_lock);
>>> +     if (no_reply)
>>> +             return 0;
>>> +
>>> +     wait_event_killable_timeout(msg->waitq, msg->completed,
>>> +                                 VDUSE_REQUEST_TIMEOUT * HZ);
>>> +     spin_lock(&dev->msg_lock);
>>> +     if (!msg->completed) {
>>> +             list_del(&msg->list);
>>> +             msg->resp.result = VDUSE_REQ_RESULT_FAILED;
>>> +     }
>>> +     spin_unlock(&dev->msg_lock);
>>> +
>>> +     return (msg->resp.result == VDUSE_REQ_RESULT_OK) ? 0 : -EIO;
>>
>> Do we need to serialize the check by protecting it with the spinlock above?
>>
> Good point.
>
>>> +}
>>> +
>>> +static void vduse_dev_msg_cleanup(struct vduse_dev *dev)
>>> +{
>>> +     struct vduse_dev_msg *msg;
>>> +
>>> +     spin_lock(&dev->msg_lock);
>>> +     while ((msg = vduse_dequeue_msg(&dev->send_list))) {
>>> +             if (msg->req.flags & VDUSE_REQ_FLAGS_NO_REPLY)
>>> +                     kfree(msg);
>>> +             else
>>> +                     vduse_enqueue_msg(&dev->recv_list, msg);
>>> +     }
>>> +     while ((msg = vduse_dequeue_msg(&dev->recv_list))) {
>>> +             msg->resp.result = VDUSE_REQ_RESULT_FAILED;
>>> +             msg->completed = 1;
>>> +             wake_up(&msg->waitq);
>>> +     }
>>> +     spin_unlock(&dev->msg_lock);
>>> +}
>>> +
>>> +static void vduse_dev_start_dataplane(struct vduse_dev *dev)
>>> +{
>>> +     struct vduse_dev_msg *msg = kzalloc(sizeof(*msg),
>>> +                                         GFP_KERNEL | __GFP_NOFAIL);
>>> +
>>> +     msg->req.type = VDUSE_START_DATAPLANE;
>>> +     msg->req.flags |= VDUSE_REQ_FLAGS_NO_REPLY;
>>> +     vduse_dev_msg_send(dev, msg, true);
>>> +}
>>> +
>>> +static void vduse_dev_stop_dataplane(struct vduse_dev *dev)
>>> +{
>>> +     struct vduse_dev_msg *msg = kzalloc(sizeof(*msg),
>>> +                                         GFP_KERNEL | __GFP_NOFAIL);
>>> +
>>> +     msg->req.type = VDUSE_STOP_DATAPLANE;
>>> +     msg->req.flags |= VDUSE_REQ_FLAGS_NO_REPLY;
>>
>> Can we simply use this flag instead of introducing a new parameter
>> (no_reply) in vduse_dev_msg_send()?
>>
> Looks good to me.
>
>>> +     vduse_dev_msg_send(dev, msg, true);
>>> +}
>>> +
>>> +static int vduse_dev_get_vq_state(struct vduse_dev *dev,
>>> +                               struct vduse_virtqueue *vq,
>>> +                               struct vdpa_vq_state *state)
>>> +{
>>> +     struct vduse_dev_msg msg = { 0 };
>>> +     int ret;
>>
>> Note that I post a series that implement the packed virtqueue support:
>>
>> https://lists.linuxfoundation.org/pipermail/virtualization/2021-June/054501.html
>>
>> So this patch needs to be updated as well.
>>
> Will do it.
>
>>> +
>>> +     msg.req.type = VDUSE_GET_VQ_STATE;
>>> +     msg.req.vq_state.index = vq->index;
>>> +
>>> +     ret = vduse_dev_msg_send(dev, &msg, false);
>>> +     if (ret)
>>> +             return ret;
>>> +
>>> +     state->avail_index = msg.resp.vq_state.avail_idx;
>>> +     return 0;
>>> +}
>>> +
>>> +static int vduse_dev_update_iotlb(struct vduse_dev *dev,
>>> +                             u64 start, u64 last)
>>> +{
>>> +     struct vduse_dev_msg msg = { 0 };
>>> +
>>> +     if (last < start)
>>> +             return -EINVAL;
>>> +
>>> +     msg.req.type = VDUSE_UPDATE_IOTLB;
>>> +     msg.req.iova.start = start;
>>> +     msg.req.iova.last = last;
>>> +
>>> +     return vduse_dev_msg_send(dev, &msg, false);
>>> +}
>>> +
>>> +static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to)
>>> +{
>>> +     struct file *file = iocb->ki_filp;
>>> +     struct vduse_dev *dev = file->private_data;
>>> +     struct vduse_dev_msg *msg;
>>> +     int size = sizeof(struct vduse_dev_request);
>>> +     ssize_t ret;
>>> +
>>> +     if (iov_iter_count(to) < size)
>>> +             return -EINVAL;
>>> +
>>> +     spin_lock(&dev->msg_lock);
>>> +     while (1) {
>>> +             msg = vduse_dequeue_msg(&dev->send_list);
>>> +             if (msg)
>>> +                     break;
>>> +
>>> +             ret = -EAGAIN;
>>> +             if (file->f_flags & O_NONBLOCK)
>>> +                     goto unlock;
>>> +
>>> +             spin_unlock(&dev->msg_lock);
>>> +             ret = wait_event_interruptible_exclusive(dev->waitq,
>>> +                                     !list_empty(&dev->send_list));
>>> +             if (ret)
>>> +                     return ret;
>>> +
>>> +             spin_lock(&dev->msg_lock);
>>> +     }
>>> +     spin_unlock(&dev->msg_lock);
>>> +     ret = copy_to_iter(&msg->req, size, to);
>>> +     spin_lock(&dev->msg_lock);
>>> +     if (ret != size) {
>>> +             ret = -EFAULT;
>>> +             vduse_enqueue_msg(&dev->send_list, msg);
>>> +             goto unlock;
>>> +     }
>>> +     if (msg->req.flags & VDUSE_REQ_FLAGS_NO_REPLY)
>>> +             kfree(msg);
>>> +     else
>>> +             vduse_enqueue_msg(&dev->recv_list, msg);
>>> +unlock:
>>> +     spin_unlock(&dev->msg_lock);
>>> +
>>> +     return ret;
>>> +}
>>> +
>>> +static ssize_t vduse_dev_write_iter(struct kiocb *iocb, struct iov_iter *from)
>>> +{
>>> +     struct file *file = iocb->ki_filp;
>>> +     struct vduse_dev *dev = file->private_data;
>>> +     struct vduse_dev_response resp;
>>> +     struct vduse_dev_msg *msg;
>>> +     size_t ret;
>>> +
>>> +     ret = copy_from_iter(&resp, sizeof(resp), from);
>>> +     if (ret != sizeof(resp))
>>> +             return -EINVAL;
>>> +
>>> +     spin_lock(&dev->msg_lock);
>>> +     msg = vduse_find_msg(&dev->recv_list, resp.request_id);
>>> +     if (!msg) {
>>> +             ret = -ENOENT;
>>> +             goto unlock;
>>> +     }
>>> +
>>> +     memcpy(&msg->resp, &resp, sizeof(resp));
>>> +     msg->completed = 1;
>>> +     wake_up(&msg->waitq);
>>> +unlock:
>>> +     spin_unlock(&dev->msg_lock);
>>> +
>>> +     return ret;
>>> +}
>>> +
>>> +static __poll_t vduse_dev_poll(struct file *file, poll_table *wait)
>>> +{
>>> +     struct vduse_dev *dev = file->private_data;
>>> +     __poll_t mask = 0;
>>> +
>>> +     poll_wait(file, &dev->waitq, wait);
>>> +
>>> +     if (!list_empty(&dev->send_list))
>>> +             mask |= EPOLLIN | EPOLLRDNORM;
>>> +     if (!list_empty(&dev->recv_list))
>>> +             mask |= EPOLLOUT | EPOLLWRNORM;
>>> +
>>> +     return mask;
>>> +}
>>> +
>>> +static void vduse_dev_reset(struct vduse_dev *dev)
>>> +{
>>> +     int i;
>>> +     struct vduse_iova_domain *domain = dev->domain;
>>> +
>>> +     /* The coherent mappings are handled in vduse_dev_free_coherent() */
>>> +     if (domain->bounce_map)
>>> +             vduse_domain_reset_bounce_map(domain);
>>> +
>>> +     dev->features = 0;
>>> +     dev->generation++;
>>> +     spin_lock(&dev->irq_lock);
>>> +     dev->config_cb.callback = NULL;
>>> +     dev->config_cb.private = NULL;
>>> +     spin_unlock(&dev->irq_lock);
>>> +
>>> +     for (i = 0; i < dev->vq_num; i++) {
>>> +             struct vduse_virtqueue *vq = &dev->vqs[i];
>>> +
>>> +             vq->ready = false;
>>> +             vq->desc_addr = 0;
>>> +             vq->driver_addr = 0;
>>> +             vq->device_addr = 0;
>>> +             vq->avail_idx = 0;
>>> +             vq->num = 0;
>>> +
>>> +             spin_lock(&vq->kick_lock);
>>> +             vq->kicked = false;
>>> +             if (vq->kickfd)
>>> +                     eventfd_ctx_put(vq->kickfd);
>>> +             vq->kickfd = NULL;
>>> +             spin_unlock(&vq->kick_lock);
>>> +
>>> +             spin_lock(&vq->irq_lock);
>>> +             vq->cb.callback = NULL;
>>> +             vq->cb.private = NULL;
>>> +             spin_unlock(&vq->irq_lock);
>>> +     }
>>> +}
>>> +
>>> +static int vduse_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 idx,
>>> +                             u64 desc_area, u64 driver_area,
>>> +                             u64 device_area)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
>>> +
>>> +     vq->desc_addr = desc_area;
>>> +     vq->driver_addr = driver_area;
>>> +     vq->device_addr = device_area;
>>> +
>>> +     return 0;
>>> +}
>>> +
>>> +static void vduse_vdpa_kick_vq(struct vdpa_device *vdpa, u16 idx)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
>>> +
>>> +     spin_lock(&vq->kick_lock);
>>> +     if (!vq->ready)
>>> +             goto unlock;
>>> +
>>> +     if (vq->kickfd)
>>> +             eventfd_signal(vq->kickfd, 1);
>>> +     else
>>> +             vq->kicked = true;
>>> +unlock:
>>> +     spin_unlock(&vq->kick_lock);
>>> +}
>>> +
>>> +static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,
>>> +                           struct vdpa_callback *cb)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
>>> +
>>> +     spin_lock(&vq->irq_lock);
>>> +     vq->cb.callback = cb->callback;
>>> +     vq->cb.private = cb->private;
>>> +     spin_unlock(&vq->irq_lock);
>>> +}
>>> +
>>> +static void vduse_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
>>> +
>>> +     vq->num = num;
>>> +}
>>> +
>>> +static void vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa,
>>> +                                     u16 idx, bool ready)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
>>> +
>>> +     vq->ready = ready;
>>> +}
>>> +
>>> +static bool vduse_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 idx)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
>>> +
>>> +     return vq->ready;
>>> +}
>>> +
>>> +static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,
>>> +                             const struct vdpa_vq_state *state)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
>>> +
>>> +     vq->avail_idx = state->avail_index;
>>> +     return 0;
>>> +}
>>> +
>>> +static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
>>> +                             struct vdpa_vq_state *state)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
>>> +
>>> +     return vduse_dev_get_vq_state(dev, vq, state);
>>> +}
>>> +
>>> +static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> +     return dev->vq_align;
>>> +}
>>> +
>>> +static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> +     return dev->user_features;
>>> +}
>>> +
>>> +static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> +     dev->features = features;
>>> +     return 0;
>>> +}
>>> +
>>> +static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,
>>> +                               struct vdpa_callback *cb)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> +     spin_lock(&dev->irq_lock);
>>> +     dev->config_cb.callback = cb->callback;
>>> +     dev->config_cb.private = cb->private;
>>> +     spin_unlock(&dev->irq_lock);
>>> +}
>>> +
>>> +static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> +     return dev->vq_size_max;
>>> +}
>>> +
>>> +static u32 vduse_vdpa_get_device_id(struct vdpa_device *vdpa)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> +     return dev->device_id;
>>> +}
>>> +
>>> +static u32 vduse_vdpa_get_vendor_id(struct vdpa_device *vdpa)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> +     return dev->vendor_id;
>>> +}
>>> +
>>> +static u8 vduse_vdpa_get_status(struct vdpa_device *vdpa)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> +     return dev->status;
>>> +}
>>> +
>>> +static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +     bool started = !!(status & VIRTIO_CONFIG_S_DRIVER_OK);
>>> +
>>> +     dev->status = status;
>>> +
>>> +     if (dev->started == started)
>>> +             return;
>>
>> If we check dev->status == status, (or only check the DRIVER_OK bit)
>> then there's no need to introduce an extra dev->started.
>>
> Will do it.
>
>>> +
>>> +     dev->started = started;
>>> +     if (dev->started) {
>>> +             vduse_dev_start_dataplane(dev);
>>> +     } else {
>>> +             vduse_dev_reset(dev);
>>> +             vduse_dev_stop_dataplane(dev);
>>
>> I wonder if no_reply work for the case of vhost-vdpa. For virtio-vDPA,
>> we have bouncing buffers so it's harmless if usersapce dataplane keeps
>> performing read/write. For vhost-vDPA we don't have such stuffs.
>>
> OK. So it still needs to be synchronized here. If so, how to handle
> the error? Looks like printing a warning message should be enough.


We need fix a way to propagate the error to the userspace.

E.g if we want to stop the deivce, we will delay the status reset until 
we get respose from the userspace?


>
>>> +     }
>>> +}
>>> +
>>> +static size_t vduse_vdpa_get_config_size(struct vdpa_device *vdpa)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> +     return dev->config_size;
>>> +}
>>> +
>>> +static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,
>>> +                               void *buf, unsigned int len)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> +     memcpy(buf, dev->config + offset, len);
>>> +}
>>> +
>>> +static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,
>>> +                     const void *buf, unsigned int len)
>>> +{
>>> +     /* Now we only support read-only configuration space */
>>> +}
>>> +
>>> +static u32 vduse_vdpa_get_generation(struct vdpa_device *vdpa)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> +     return dev->generation;
>>> +}
>>> +
>>> +static int vduse_vdpa_set_map(struct vdpa_device *vdpa,
>>> +                             struct vhost_iotlb *iotlb)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +     int ret;
>>> +
>>> +     ret = vduse_domain_set_map(dev->domain, iotlb);
>>> +     if (ret)
>>> +             return ret;
>>> +
>>> +     ret = vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
>>> +     if (ret) {
>>> +             vduse_domain_clear_map(dev->domain, iotlb);
>>> +             return ret;
>>> +     }
>>> +
>>> +     return 0;
>>> +}
>>> +
>>> +static void vduse_vdpa_free(struct vdpa_device *vdpa)
>>> +{
>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> +     dev->vdev = NULL;
>>> +}
>>> +
>>> +static const struct vdpa_config_ops vduse_vdpa_config_ops = {
>>> +     .set_vq_address         = vduse_vdpa_set_vq_address,
>>> +     .kick_vq                = vduse_vdpa_kick_vq,
>>> +     .set_vq_cb              = vduse_vdpa_set_vq_cb,
>>> +     .set_vq_num             = vduse_vdpa_set_vq_num,
>>> +     .set_vq_ready           = vduse_vdpa_set_vq_ready,
>>> +     .get_vq_ready           = vduse_vdpa_get_vq_ready,
>>> +     .set_vq_state           = vduse_vdpa_set_vq_state,
>>> +     .get_vq_state           = vduse_vdpa_get_vq_state,
>>> +     .get_vq_align           = vduse_vdpa_get_vq_align,
>>> +     .get_features           = vduse_vdpa_get_features,
>>> +     .set_features           = vduse_vdpa_set_features,
>>> +     .set_config_cb          = vduse_vdpa_set_config_cb,
>>> +     .get_vq_num_max         = vduse_vdpa_get_vq_num_max,
>>> +     .get_device_id          = vduse_vdpa_get_device_id,
>>> +     .get_vendor_id          = vduse_vdpa_get_vendor_id,
>>> +     .get_status             = vduse_vdpa_get_status,
>>> +     .set_status             = vduse_vdpa_set_status,
>>> +     .get_config_size        = vduse_vdpa_get_config_size,
>>> +     .get_config             = vduse_vdpa_get_config,
>>> +     .set_config             = vduse_vdpa_set_config,
>>> +     .get_generation         = vduse_vdpa_get_generation,
>>> +     .set_map                = vduse_vdpa_set_map,
>>> +     .free                   = vduse_vdpa_free,
>>> +};
>>> +
>>> +static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,
>>> +                                  unsigned long offset, size_t size,
>>> +                                  enum dma_data_direction dir,
>>> +                                  unsigned long attrs)
>>> +{
>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
>>> +     struct vduse_iova_domain *domain = vdev->domain;
>>> +
>>> +     return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
>>> +}
>>> +
>>> +static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,
>>> +                             size_t size, enum dma_data_direction dir,
>>> +                             unsigned long attrs)
>>> +{
>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
>>> +     struct vduse_iova_domain *domain = vdev->domain;
>>> +
>>> +     return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
>>> +}
>>> +
>>> +static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,
>>> +                                     dma_addr_t *dma_addr, gfp_t flag,
>>> +                                     unsigned long attrs)
>>> +{
>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
>>> +     struct vduse_iova_domain *domain = vdev->domain;
>>> +     unsigned long iova;
>>> +     void *addr;
>>> +
>>> +     *dma_addr = DMA_MAPPING_ERROR;
>>> +     addr = vduse_domain_alloc_coherent(domain, size,
>>> +                             (dma_addr_t *)&iova, flag, attrs);
>>> +     if (!addr)
>>> +             return NULL;
>>> +
>>> +     *dma_addr = (dma_addr_t)iova;
>>> +
>>> +     return addr;
>>> +}
>>> +
>>> +static void vduse_dev_free_coherent(struct device *dev, size_t size,
>>> +                                     void *vaddr, dma_addr_t dma_addr,
>>> +                                     unsigned long attrs)
>>> +{
>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
>>> +     struct vduse_iova_domain *domain = vdev->domain;
>>> +
>>> +     vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
>>> +}
>>> +
>>> +static size_t vduse_dev_max_mapping_size(struct device *dev)
>>> +{
>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
>>> +     struct vduse_iova_domain *domain = vdev->domain;
>>> +
>>> +     return domain->bounce_size;
>>> +}
>>> +
>>> +static const struct dma_map_ops vduse_dev_dma_ops = {
>>> +     .map_page = vduse_dev_map_page,
>>> +     .unmap_page = vduse_dev_unmap_page,
>>> +     .alloc = vduse_dev_alloc_coherent,
>>> +     .free = vduse_dev_free_coherent,
>>> +     .max_mapping_size = vduse_dev_max_mapping_size,
>>> +};
>>> +
>>> +static unsigned int perm_to_file_flags(u8 perm)
>>> +{
>>> +     unsigned int flags = 0;
>>> +
>>> +     switch (perm) {
>>> +     case VDUSE_ACCESS_WO:
>>> +             flags |= O_WRONLY;
>>> +             break;
>>> +     case VDUSE_ACCESS_RO:
>>> +             flags |= O_RDONLY;
>>> +             break;
>>> +     case VDUSE_ACCESS_RW:
>>> +             flags |= O_RDWR;
>>> +             break;
>>> +     default:
>>> +             WARN(1, "invalidate vhost IOTLB permission\n");
>>> +             break;
>>> +     }
>>> +
>>> +     return flags;
>>> +}
>>> +
>>> +static int vduse_kickfd_setup(struct vduse_dev *dev,
>>> +                     struct vduse_vq_eventfd *eventfd)
>>> +{
>>> +     struct eventfd_ctx *ctx = NULL;
>>> +     struct vduse_virtqueue *vq;
>>> +     u32 index;
>>> +
>>> +     if (eventfd->index >= dev->vq_num)
>>> +             return -EINVAL;
>>> +
>>> +     index = array_index_nospec(eventfd->index, dev->vq_num);
>>> +     vq = &dev->vqs[index];
>>> +     if (eventfd->fd >= 0) {
>>> +             ctx = eventfd_ctx_fdget(eventfd->fd);
>>> +             if (IS_ERR(ctx))
>>> +                     return PTR_ERR(ctx);
>>> +     } else if (eventfd->fd != VDUSE_EVENTFD_DEASSIGN)
>>> +             return 0;
>>> +
>>> +     spin_lock(&vq->kick_lock);
>>> +     if (vq->kickfd)
>>> +             eventfd_ctx_put(vq->kickfd);
>>> +     vq->kickfd = ctx;
>>> +     if (vq->ready && vq->kicked && vq->kickfd) {
>>> +             eventfd_signal(vq->kickfd, 1);
>>> +             vq->kicked = false;
>>> +     }
>>> +     spin_unlock(&vq->kick_lock);
>>> +
>>> +     return 0;
>>> +}
>>> +
>>> +static void vduse_dev_irq_inject(struct work_struct *work)
>>> +{
>>> +     struct vduse_dev *dev = container_of(work, struct vduse_dev, inject);
>>> +
>>> +     spin_lock_irq(&dev->irq_lock);
>>> +     if (dev->config_cb.callback)
>>> +             dev->config_cb.callback(dev->config_cb.private);
>>> +     spin_unlock_irq(&dev->irq_lock);
>>> +}
>>> +
>>> +static void vduse_vq_irq_inject(struct work_struct *work)
>>> +{
>>> +     struct vduse_virtqueue *vq = container_of(work,
>>> +                                     struct vduse_virtqueue, inject);
>>> +
>>> +     spin_lock_irq(&vq->irq_lock);
>>> +     if (vq->ready && vq->cb.callback)
>>> +             vq->cb.callback(vq->cb.private);
>>> +     spin_unlock_irq(&vq->irq_lock);
>>> +}
>>> +
>>> +static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
>>> +                         unsigned long arg)
>>> +{
>>> +     struct vduse_dev *dev = file->private_data;
>>> +     void __user *argp = (void __user *)arg;
>>> +     int ret;
>>> +
>>> +     switch (cmd) {
>>> +     case VDUSE_IOTLB_GET_FD: {
>>> +             struct vduse_iotlb_entry entry;
>>> +             struct vhost_iotlb_map *map;
>>> +             struct vdpa_map_file *map_file;
>>> +             struct vduse_iova_domain *domain = dev->domain;
>>> +             struct file *f = NULL;
>>> +
>>> +             ret = -EFAULT;
>>> +             if (copy_from_user(&entry, argp, sizeof(entry)))
>>> +                     break;
>>> +
>>> +             ret = -EINVAL;
>>> +             if (entry.start > entry.last)
>>> +                     break;
>>> +
>>> +             spin_lock(&domain->iotlb_lock);
>>> +             map = vhost_iotlb_itree_first(domain->iotlb,
>>> +                                           entry.start, entry.last);
>>> +             if (map) {
>>> +                     map_file = (struct vdpa_map_file *)map->opaque;
>>> +                     f = get_file(map_file->file);
>>> +                     entry.offset = map_file->offset;
>>> +                     entry.start = map->start;
>>> +                     entry.last = map->last;
>>> +                     entry.perm = map->perm;
>>> +             }
>>> +             spin_unlock(&domain->iotlb_lock);
>>> +             ret = -EINVAL;
>>> +             if (!f)
>>> +                     break;
>>> +
>>> +             ret = -EFAULT;
>>> +             if (copy_to_user(argp, &entry, sizeof(entry))) {
>>> +                     fput(f);
>>> +                     break;
>>> +             }
>>> +             ret = receive_fd(f, perm_to_file_flags(entry.perm));
>>> +             fput(f);
>>> +             break;
>>> +     }
>>> +     case VDUSE_DEV_GET_FEATURES:
>>> +             ret = put_user(dev->features, (u64 __user *)argp);
>>> +             break;
>>> +     case VDUSE_DEV_UPDATE_CONFIG: {
>>> +             struct vduse_config_update config;
>>> +             unsigned long size = offsetof(struct vduse_config_update,
>>> +                                           buffer);
>>> +
>>> +             ret = -EFAULT;
>>> +             if (copy_from_user(&config, argp, size))
>>> +                     break;
>>> +
>>> +             ret = -EINVAL;
>>> +             if (config.length == 0 ||
>>> +                 config.length > dev->config_size - config.offset)
>>> +                     break;
>>> +
>>> +             ret = -EFAULT;
>>> +             if (copy_from_user(dev->config + config.offset, argp + size,
>>> +                                config.length))
>>> +                     break;
>>> +
>>> +             ret = 0;
>>> +             queue_work(vduse_irq_wq, &dev->inject);
>>
>> I wonder if it's better to separate config interrupt out of config
>> update or we need document this.
>>
> I have documented it in the docs. Looks like a config update should be
> always followed by a config interrupt. I didn't find a case that uses
> them separately.


The uAPI doesn't prevent us from the following scenario:

update_config(mac[0], ..);
update_config(max[1], ..);

So it looks to me it's better to separate the config interrupt from the 
config updating.


>
>>> +             break;
>>> +     }
>>> +     case VDUSE_VQ_GET_INFO: {
>>
>> Do we need to limit this only when DRIVER_OK is set?
>>
> Any reason to add this limitation?


Otherwise the vq is not fully initialized, e.g the desc_addr might not 
be correct.


>
>>> +             struct vduse_vq_info vq_info;
>>> +             u32 vq_index;
>>> +
>>> +             ret = -EFAULT;
>>> +             if (copy_from_user(&vq_info, argp, sizeof(vq_info)))
>>> +                     break;
>>> +
>>> +             ret = -EINVAL;
>>> +             if (vq_info.index >= dev->vq_num)
>>> +                     break;
>>> +
>>> +             vq_index = array_index_nospec(vq_info.index, dev->vq_num);
>>> +             vq_info.desc_addr = dev->vqs[vq_index].desc_addr;
>>> +             vq_info.driver_addr = dev->vqs[vq_index].driver_addr;
>>> +             vq_info.device_addr = dev->vqs[vq_index].device_addr;
>>> +             vq_info.num = dev->vqs[vq_index].num;
>>> +             vq_info.avail_idx = dev->vqs[vq_index].avail_idx;
>>> +             vq_info.ready = dev->vqs[vq_index].ready;
>>> +
>>> +             ret = -EFAULT;
>>> +             if (copy_to_user(argp, &vq_info, sizeof(vq_info)))
>>> +                     break;
>>> +
>>> +             ret = 0;
>>> +             break;
>>> +     }
>>> +     case VDUSE_VQ_SETUP_KICKFD: {
>>> +             struct vduse_vq_eventfd eventfd;
>>> +
>>> +             ret = -EFAULT;
>>> +             if (copy_from_user(&eventfd, argp, sizeof(eventfd)))
>>> +                     break;
>>> +
>>> +             ret = vduse_kickfd_setup(dev, &eventfd);
>>> +             break;
>>> +     }
>>> +     case VDUSE_VQ_INJECT_IRQ: {
>>> +             u32 vq_index;
>>> +
>>> +             ret = -EFAULT;
>>> +             if (get_user(vq_index, (u32 __user *)argp))
>>> +                     break;
>>> +
>>> +             ret = -EINVAL;
>>> +             if (vq_index >= dev->vq_num)
>>> +                     break;
>>> +
>>> +             ret = 0;
>>> +             vq_index = array_index_nospec(vq_index, dev->vq_num);
>>> +             queue_work(vduse_irq_wq, &dev->vqs[vq_index].inject);
>>> +             break;
>>> +     }
>>> +     default:
>>> +             ret = -ENOIOCTLCMD;
>>> +             break;
>>> +     }
>>> +
>>> +     return ret;
>>> +}
>>> +
>>> +static int vduse_dev_release(struct inode *inode, struct file *file)
>>> +{
>>> +     struct vduse_dev *dev = file->private_data;
>>> +
>>> +     spin_lock(&dev->msg_lock);
>>> +     /* Make sure the inflight messages can processed after reconncection */
>>> +     list_splice_init(&dev->recv_list, &dev->send_list);
>>> +     spin_unlock(&dev->msg_lock);
>>> +     dev->connected = false;
>>> +
>>> +     return 0;
>>> +}
>>> +
>>> +static struct vduse_dev *vduse_dev_get_from_minor(int minor)
>>> +{
>>> +     struct vduse_dev *dev;
>>> +
>>> +     mutex_lock(&vduse_lock);
>>> +     dev = idr_find(&vduse_idr, minor);
>>> +     mutex_unlock(&vduse_lock);
>>> +
>>> +     return dev;
>>> +}
>>> +
>>> +static int vduse_dev_open(struct inode *inode, struct file *file)
>>> +{
>>> +     int ret;
>>> +     struct vduse_dev *dev = vduse_dev_get_from_minor(iminor(inode));
>>> +
>>> +     if (!dev)
>>> +             return -ENODEV;
>>> +
>>> +     ret = -EBUSY;
>>> +     mutex_lock(&dev->lock);
>>> +     if (dev->connected)
>>> +             goto unlock;
>>> +
>>> +     ret = 0;
>>> +     dev->connected = true;
>>> +     file->private_data = dev;
>>> +unlock:
>>> +     mutex_unlock(&dev->lock);
>>> +
>>> +     return ret;
>>> +}
>>> +
>>> +static const struct file_operations vduse_dev_fops = {
>>> +     .owner          = THIS_MODULE,
>>> +     .open           = vduse_dev_open,
>>> +     .release        = vduse_dev_release,
>>> +     .read_iter      = vduse_dev_read_iter,
>>> +     .write_iter     = vduse_dev_write_iter,
>>> +     .poll           = vduse_dev_poll,
>>> +     .unlocked_ioctl = vduse_dev_ioctl,
>>> +     .compat_ioctl   = compat_ptr_ioctl,
>>> +     .llseek         = noop_llseek,
>>> +};
>>> +
>>> +static struct vduse_dev *vduse_dev_create(void)
>>> +{
>>> +     struct vduse_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
>>> +
>>> +     if (!dev)
>>> +             return NULL;
>>> +
>>> +     mutex_init(&dev->lock);
>>> +     spin_lock_init(&dev->msg_lock);
>>> +     INIT_LIST_HEAD(&dev->send_list);
>>> +     INIT_LIST_HEAD(&dev->recv_list);
>>> +     spin_lock_init(&dev->irq_lock);
>>> +
>>> +     INIT_WORK(&dev->inject, vduse_dev_irq_inject);
>>> +     init_waitqueue_head(&dev->waitq);
>>> +
>>> +     return dev;
>>> +}
>>> +
>>> +static void vduse_dev_destroy(struct vduse_dev *dev)
>>> +{
>>> +     kfree(dev);
>>> +}
>>> +
>>> +static struct vduse_dev *vduse_find_dev(const char *name)
>>> +{
>>> +     struct vduse_dev *dev;
>>> +     int id;
>>> +
>>> +     idr_for_each_entry(&vduse_idr, dev, id)
>>> +             if (!strcmp(dev->name, name))
>>> +                     return dev;
>>> +
>>> +     return NULL;
>>> +}
>>> +
>>> +static int vduse_destroy_dev(char *name)
>>> +{
>>> +     struct vduse_dev *dev = vduse_find_dev(name);
>>> +
>>> +     if (!dev)
>>> +             return -EINVAL;
>>> +
>>> +     mutex_lock(&dev->lock);
>>> +     if (dev->vdev || dev->connected) {
>>> +             mutex_unlock(&dev->lock);
>>> +             return -EBUSY;
>>> +     }
>>> +     dev->connected = true;
>>> +     mutex_unlock(&dev->lock);
>>> +
>>> +     vduse_dev_msg_cleanup(dev);
>>> +     device_destroy(vduse_class, MKDEV(MAJOR(vduse_major), dev->minor));
>>> +     idr_remove(&vduse_idr, dev->minor);
>>> +     kvfree(dev->config);
>>> +     kfree(dev->vqs);
>>> +     vduse_domain_destroy(dev->domain);
>>> +     kfree(dev->name);
>>> +     vduse_dev_destroy(dev);
>>> +     module_put(THIS_MODULE);
>>> +
>>> +     return 0;
>>> +}
>>> +
>>> +static bool device_is_allowed(u32 device_id)
>>> +{
>>> +     int i;
>>> +
>>> +     for (i = 0; i < ARRAY_SIZE(allowed_device_id); i++)
>>> +             if (allowed_device_id[i] == device_id)
>>> +                     return true;
>>> +
>>> +     return false;
>>> +}
>>> +
>>> +static bool features_is_valid(u64 features)
>>> +{
>>> +     if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))
>>> +             return false;
>>> +
>>> +     /* Now we only support read-only configuration space */
>>> +     if (features & (1ULL << VIRTIO_BLK_F_CONFIG_WCE))
>>> +             return false;
>>> +
>>> +     return true;
>>> +}
>>> +
>>> +static bool vduse_validate_config(struct vduse_dev_config *config)
>>> +{
>>> +     if (config->bounce_size > VDUSE_MAX_BOUNCE_SIZE)
>>> +             return false;
>>> +
>>> +     if (config->vq_align > PAGE_SIZE)
>>> +             return false;
>>> +
>>> +     if (config->config_size > PAGE_SIZE)
>>> +             return false;
>>> +
>>> +     if (!device_is_allowed(config->device_id))
>>> +             return false;
>>> +
>>> +     if (!features_is_valid(config->features))
>>> +             return false;
>>
>> Do we need to validate whether or not config_size is too small otherwise
>> we may have OOB access in get_config()?
>>
> How about adding validation in get_config()? It seems to be hard to
> define the lower bound.


It should work.

Thanks


>
>>> +
>>> +     return true;
>>> +}
>>> +
>>> +static int vduse_create_dev(struct vduse_dev_config *config,
>>> +                         void *config_buf, u64 api_version)
>>> +{
>>> +     int i, ret;
>>> +     struct vduse_dev *dev;
>>> +
>>> +     ret = -EEXIST;
>>> +     if (vduse_find_dev(config->name))
>>> +             goto err;
>>> +
>>> +     ret = -ENOMEM;
>>> +     dev = vduse_dev_create();
>>> +     if (!dev)
>>> +             goto err;
>>> +
>>> +     dev->api_version = api_version;
>>> +     dev->user_features = config->features;
>>> +     dev->device_id = config->device_id;
>>> +     dev->vendor_id = config->vendor_id;
>>> +     dev->name = kstrdup(config->name, GFP_KERNEL);
>>> +     if (!dev->name)
>>> +             goto err_str;
>>> +
>>> +     dev->domain = vduse_domain_create(VDUSE_IOVA_SIZE - 1,
>>> +                                       config->bounce_size);
>>> +     if (!dev->domain)
>>> +             goto err_domain;
>>> +
>>> +     dev->config = config_buf;
>>> +     dev->config_size = config->config_size;
>>> +     dev->vq_align = config->vq_align;
>>> +     dev->vq_size_max = config->vq_size_max;
>>> +     dev->vq_num = config->vq_num;
>>> +     dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), GFP_KERNEL);
>>> +     if (!dev->vqs)
>>> +             goto err_vqs;
>>> +
>>> +     for (i = 0; i < dev->vq_num; i++) {
>>> +             dev->vqs[i].index = i;
>>> +             INIT_WORK(&dev->vqs[i].inject, vduse_vq_irq_inject);
>>> +             spin_lock_init(&dev->vqs[i].kick_lock);
>>> +             spin_lock_init(&dev->vqs[i].irq_lock);
>>> +     }
>>> +
>>> +     ret = idr_alloc(&vduse_idr, dev, 1, VDUSE_DEV_MAX, GFP_KERNEL);
>>> +     if (ret < 0)
>>> +             goto err_idr;
>>> +
>>> +     dev->minor = ret;
>>> +     dev->dev = device_create(vduse_class, NULL,
>>> +                              MKDEV(MAJOR(vduse_major), dev->minor),
>>> +                              NULL, "%s", config->name);
>>> +     if (IS_ERR(dev->dev)) {
>>> +             ret = PTR_ERR(dev->dev);
>>> +             goto err_dev;
>>> +     }
>>> +     __module_get(THIS_MODULE);
>>> +
>>> +     return 0;
>>> +err_dev:
>>> +     idr_remove(&vduse_idr, dev->minor);
>>> +err_idr:
>>> +     kfree(dev->vqs);
>>> +err_vqs:
>>> +     vduse_domain_destroy(dev->domain);
>>> +err_domain:
>>> +     kfree(dev->name);
>>> +err_str:
>>> +     vduse_dev_destroy(dev);
>>> +err:
>>> +     kvfree(config_buf);
>>> +     return ret;
>>> +}
>>> +
>>> +static long vduse_ioctl(struct file *file, unsigned int cmd,
>>> +                     unsigned long arg)
>>> +{
>>> +     int ret;
>>> +     void __user *argp = (void __user *)arg;
>>> +     struct vduse_control *control = file->private_data;
>>> +
>>> +     mutex_lock(&vduse_lock);
>>> +     switch (cmd) {
>>> +     case VDUSE_GET_API_VERSION:
>>> +             ret = put_user(control->api_version, (u64 __user *)argp);
>>> +             break;
>>> +     case VDUSE_SET_API_VERSION: {
>>> +             u64 api_version;
>>> +
>>> +             ret = -EFAULT;
>>> +             if (get_user(api_version, (u64 __user *)argp))
>>> +                     break;
>>> +
>>> +             ret = -EINVAL;
>>> +             if (api_version > VDUSE_API_VERSION)
>>> +                     break;
>>> +
>>> +             ret = 0;
>>> +             control->api_version = api_version;
>>> +             break;
>>> +     }
>>> +     case VDUSE_CREATE_DEV: {
>>> +             struct vduse_dev_config config;
>>> +             unsigned long size = offsetof(struct vduse_dev_config, config);
>>> +             void *buf;
>>> +
>>> +             ret = -EFAULT;
>>> +             if (copy_from_user(&config, argp, size))
>>> +                     break;
>>> +
>>> +             ret = -EINVAL;
>>> +             if (vduse_validate_config(&config) == false)
>>> +                     break;
>>> +
>>> +             buf = vmemdup_user(argp + size, config.config_size);
>>> +             if (IS_ERR(buf)) {
>>> +                     ret = PTR_ERR(buf);
>>> +                     break;
>>> +             }
>>> +             ret = vduse_create_dev(&config, buf, control->api_version);
>>> +             break;
>>> +     }
>>> +     case VDUSE_DESTROY_DEV: {
>>> +             char name[VDUSE_NAME_MAX];
>>> +
>>> +             ret = -EFAULT;
>>> +             if (copy_from_user(name, argp, VDUSE_NAME_MAX))
>>> +                     break;
>>> +
>>> +             ret = vduse_destroy_dev(name);
>>> +             break;
>>> +     }
>>> +     default:
>>> +             ret = -EINVAL;
>>> +             break;
>>> +     }
>>> +     mutex_unlock(&vduse_lock);
>>> +
>>> +     return ret;
>>> +}
>>> +
>>> +static int vduse_release(struct inode *inode, struct file *file)
>>> +{
>>> +     struct vduse_control *control = file->private_data;
>>> +
>>> +     kfree(control);
>>> +     return 0;
>>> +}
>>> +
>>> +static int vduse_open(struct inode *inode, struct file *file)
>>> +{
>>> +     struct vduse_control *control;
>>> +
>>> +     control = kmalloc(sizeof(struct vduse_control), GFP_KERNEL);
>>> +     if (!control)
>>> +             return -ENOMEM;
>>> +
>>> +     control->api_version = VDUSE_API_VERSION;
>>> +     file->private_data = control;
>>> +
>>> +     return 0;
>>> +}
>>> +
>>> +static const struct file_operations vduse_ctrl_fops = {
>>> +     .owner          = THIS_MODULE,
>>> +     .open           = vduse_open,
>>> +     .release        = vduse_release,
>>> +     .unlocked_ioctl = vduse_ioctl,
>>> +     .compat_ioctl   = compat_ptr_ioctl,
>>> +     .llseek         = noop_llseek,
>>> +};
>>> +
>>> +static char *vduse_devnode(struct device *dev, umode_t *mode)
>>> +{
>>> +     return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));
>>> +}
>>> +
>>> +static void vduse_mgmtdev_release(struct device *dev)
>>> +{
>>> +}
>>> +
>>> +static struct device vduse_mgmtdev = {
>>> +     .init_name = "vduse",
>>> +     .release = vduse_mgmtdev_release,
>>> +};
>>> +
>>> +static struct vdpa_mgmt_dev mgmt_dev;
>>> +
>>> +static int vduse_dev_init_vdpa(struct vduse_dev *dev, const char *name)
>>> +{
>>> +     struct vduse_vdpa *vdev;
>>> +     int ret;
>>> +
>>> +     if (dev->vdev)
>>> +             return -EEXIST;
>>> +
>>> +     vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, dev->dev,
>>> +                              &vduse_vdpa_config_ops, name, true);
>>> +     if (!vdev)
>>> +             return -ENOMEM;
>>> +
>>> +     dev->vdev = vdev;
>>> +     vdev->dev = dev;
>>> +     vdev->vdpa.dev.dma_mask = &vdev->vdpa.dev.coherent_dma_mask;
>>> +     ret = dma_set_mask_and_coherent(&vdev->vdpa.dev, DMA_BIT_MASK(64));
>>> +     if (ret) {
>>> +             put_device(&vdev->vdpa.dev);
>>> +             return ret;
>>> +     }
>>> +     set_dma_ops(&vdev->vdpa.dev, &vduse_dev_dma_ops);
>>> +     vdev->vdpa.dma_dev = &vdev->vdpa.dev;
>>> +     vdev->vdpa.mdev = &mgmt_dev;
>>> +
>>> +     return 0;
>>> +}
>>> +
>>> +static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)
>>> +{
>>> +     struct vduse_dev *dev;
>>> +     int ret;
>>> +
>>> +     mutex_lock(&vduse_lock);
>>> +     dev = vduse_find_dev(name);
>>> +     if (!dev) {
>>> +             mutex_unlock(&vduse_lock);
>>> +             return -EINVAL;
>>> +     }
>>> +     ret = vduse_dev_init_vdpa(dev, name);
>>> +     mutex_unlock(&vduse_lock);
>>> +     if (ret)
>>> +             return ret;
>>> +
>>> +     ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);
>>> +     if (ret) {
>>> +             put_device(&dev->vdev->vdpa.dev);
>>> +             return ret;
>>> +     }
>>> +
>>> +     return 0;
>>> +}
>>> +
>>> +static void vdpa_dev_del(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev)
>>> +{
>>> +     _vdpa_unregister_device(dev);
>>> +}
>>> +
>>> +static const struct vdpa_mgmtdev_ops vdpa_dev_mgmtdev_ops = {
>>> +     .dev_add = vdpa_dev_add,
>>> +     .dev_del = vdpa_dev_del,
>>> +};
>>> +
>>> +static struct virtio_device_id id_table[] = {
>>> +     { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
>>> +     { 0 },
>>> +};
>>> +
>>> +static struct vdpa_mgmt_dev mgmt_dev = {
>>> +     .device = &vduse_mgmtdev,
>>> +     .id_table = id_table,
>>> +     .ops = &vdpa_dev_mgmtdev_ops,
>>> +};
>>> +
>>> +static int vduse_mgmtdev_init(void)
>>> +{
>>> +     int ret;
>>> +
>>> +     ret = device_register(&vduse_mgmtdev);
>>> +     if (ret)
>>> +             return ret;
>>> +
>>> +     ret = vdpa_mgmtdev_register(&mgmt_dev);
>>> +     if (ret)
>>> +             goto err;
>>> +
>>> +     return 0;
>>> +err:
>>> +     device_unregister(&vduse_mgmtdev);
>>> +     return ret;
>>> +}
>>> +
>>> +static void vduse_mgmtdev_exit(void)
>>> +{
>>> +     vdpa_mgmtdev_unregister(&mgmt_dev);
>>> +     device_unregister(&vduse_mgmtdev);
>>> +}
>>> +
>>> +static int vduse_init(void)
>>> +{
>>> +     int ret;
>>> +     struct device *dev;
>>> +
>>> +     vduse_class = class_create(THIS_MODULE, "vduse");
>>> +     if (IS_ERR(vduse_class))
>>> +             return PTR_ERR(vduse_class);
>>> +
>>> +     vduse_class->devnode = vduse_devnode;
>>> +
>>> +     ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse");
>>> +     if (ret)
>>> +             goto err_chardev_region;
>>> +
>>> +     /* /dev/vduse/control */
>>> +     cdev_init(&vduse_ctrl_cdev, &vduse_ctrl_fops);
>>> +     vduse_ctrl_cdev.owner = THIS_MODULE;
>>> +     ret = cdev_add(&vduse_ctrl_cdev, vduse_major, 1);
>>> +     if (ret)
>>> +             goto err_ctrl_cdev;
>>> +
>>> +     dev = device_create(vduse_class, NULL, vduse_major, NULL, "control");
>>> +     if (IS_ERR(dev)) {
>>> +             ret = PTR_ERR(dev);
>>> +             goto err_device;
>>> +     }
>>> +
>>> +     /* /dev/vduse/$DEVICE */
>>> +     cdev_init(&vduse_cdev, &vduse_dev_fops);
>>> +     vduse_cdev.owner = THIS_MODULE;
>>> +     ret = cdev_add(&vduse_cdev, MKDEV(MAJOR(vduse_major), 1),
>>> +                    VDUSE_DEV_MAX - 1);
>>> +     if (ret)
>>> +             goto err_cdev;
>>> +
>>> +     vduse_irq_wq = alloc_workqueue("vduse-irq",
>>> +                             WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);
>>> +     if (!vduse_irq_wq)
>>> +             goto err_wq;
>>> +
>>> +     ret = vduse_domain_init();
>>> +     if (ret)
>>> +             goto err_domain;
>>> +
>>> +     ret = vduse_mgmtdev_init();
>>> +     if (ret)
>>> +             goto err_mgmtdev;
>>> +
>>> +     return 0;
>>> +err_mgmtdev:
>>> +     vduse_domain_exit();
>>> +err_domain:
>>> +     destroy_workqueue(vduse_irq_wq);
>>> +err_wq:
>>> +     cdev_del(&vduse_cdev);
>>> +err_cdev:
>>> +     device_destroy(vduse_class, vduse_major);
>>> +err_device:
>>> +     cdev_del(&vduse_ctrl_cdev);
>>> +err_ctrl_cdev:
>>> +     unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
>>> +err_chardev_region:
>>> +     class_destroy(vduse_class);
>>> +     return ret;
>>> +}
>>> +module_init(vduse_init);
>>> +
>>> +static void vduse_exit(void)
>>> +{
>>> +     vduse_mgmtdev_exit();
>>> +     vduse_domain_exit();
>>> +     destroy_workqueue(vduse_irq_wq);
>>> +     cdev_del(&vduse_cdev);
>>> +     device_destroy(vduse_class, vduse_major);
>>> +     cdev_del(&vduse_ctrl_cdev);
>>> +     unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
>>> +     class_destroy(vduse_class);
>>> +}
>>> +module_exit(vduse_exit);
>>> +
>>> +MODULE_LICENSE(DRV_LICENSE);
>>> +MODULE_AUTHOR(DRV_AUTHOR);
>>> +MODULE_DESCRIPTION(DRV_DESC);
>>> diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
>>> new file mode 100644
>>> index 000000000000..f21b2e51b5c8
>>> --- /dev/null
>>> +++ b/include/uapi/linux/vduse.h
>>> @@ -0,0 +1,143 @@
>>> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
>>> +#ifndef _UAPI_VDUSE_H_
>>> +#define _UAPI_VDUSE_H_
>>> +
>>> +#include <linux/types.h>
>>> +
>>> +#define VDUSE_API_VERSION    0
>>> +
>>> +#define VDUSE_NAME_MAX       256
>>> +
>>> +/* the control messages definition for read/write */
>>> +
>>> +enum vduse_req_type {
>>> +     /* Get the state for virtqueue from userspace */
>>> +     VDUSE_GET_VQ_STATE,
>>> +     /* Notify userspace to start the dataplane, no reply */
>>> +     VDUSE_START_DATAPLANE,
>>> +     /* Notify userspace to stop the dataplane, no reply */
>>> +     VDUSE_STOP_DATAPLANE,
>>> +     /* Notify userspace to update the memory mapping in device IOTLB */
>>> +     VDUSE_UPDATE_IOTLB,
>>> +};
>>> +
>>> +struct vduse_vq_state {
>>> +     __u32 index; /* virtqueue index */
>>> +     __u32 avail_idx; /* virtqueue state (last_avail_idx) */
>>> +};
>>
>> This needs some tweaks to support packed virtqueue.
>>
> OK.
>
> Thanks,
> Yongji
>

Yongji Xie June 22, 2021, 7:22 a.m. UTC | #4

.On Tue, Jun 22, 2021 at 1:07 PM Jason Wang <[e-mail]> wrote:
>
>
> 在 2021/6/21 下午6:41, Yongji Xie 写道:
> > On Mon, Jun 21, 2021 at 5:14 PM Jason Wang <[e-mail]> wrote:
> >>
> >> 在 2021/6/15 下午10:13, Xie Yongji 写道:
> >>> This VDUSE driver enables implementing vDPA devices in userspace.
> >>> The vDPA device's control path is handled in kernel and the data
> >>> path is handled in userspace.
> >>>
> >>> A message mechnism is used by VDUSE driver to forward some control
> >>> messages such as starting/stopping datapath to userspace. Userspace
> >>> can use read()/write() to receive/reply those control messages.
> >>>
> >>> And some ioctls are introduced to help userspace to implement the
> >>> data path. VDUSE_IOTLB_GET_FD ioctl can be used to get the file
> >>> descriptors referring to vDPA device's iova regions. Then userspace
> >>> can use mmap() to access those iova regions. VDUSE_DEV_GET_FEATURES
> >>> and VDUSE_VQ_GET_INFO ioctls are used to get the negotiated features
> >>> and metadata of virtqueues. VDUSE_INJECT_VQ_IRQ and VDUSE_VQ_SETUP_KICKFD
> >>> ioctls can be used to inject interrupt and setup the kickfd for
> >>> virtqueues. VDUSE_DEV_UPDATE_CONFIG ioctl is used to update the
> >>> configuration space and inject a config interrupt.
> >>>
> >>> Signed-off-by: Xie Yongji <[e-mail]>
> >>> ---
> >>>    Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +
> >>>    drivers/vdpa/Kconfig                               |   10 +
> >>>    drivers/vdpa/Makefile                              |    1 +
> >>>    drivers/vdpa/vdpa_user/Makefile                    |    5 +
> >>>    drivers/vdpa/vdpa_user/vduse_dev.c                 | 1453 ++++++++++++++++++++
> >>>    include/uapi/linux/vduse.h                         |  143 ++
> >>>    6 files changed, 1613 insertions(+)
> >>>    create mode 100644 drivers/vdpa/vdpa_user/Makefile
> >>>    create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c
> >>>    create mode 100644 include/uapi/linux/vduse.h
> >>>
> >>> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> >>> index 9bfc2b510c64..acd95e9dcfe7 100644
> >>> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> >>> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> >>> @@ -300,6 +300,7 @@ Code  Seq#    Include File                                           Comments
> >>>    'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                        conflict!
> >>>    '|'   00-7F  linux/media.h
> >>>    0x80  00-1F  linux/fb.h
> >>> +0x81  00-1F  linux/vduse.h
> >>>    0x89  00-06  arch/x86/include/asm/sockios.h
> >>>    0x89  0B-DF  linux/sockios.h
> >>>    0x89  E0-EF  linux/sockios.h                                         SIOCPROTOPRIVATE range
> >>> diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
> >>> index a503c1b2bfd9..6e23bce6433a 100644
> >>> --- a/drivers/vdpa/Kconfig
> >>> +++ b/drivers/vdpa/Kconfig
> >>> @@ -33,6 +33,16 @@ config VDPA_SIM_BLOCK
> >>>          vDPA block device simulator which terminates IO request in a
> >>>          memory buffer.
> >>>
> >>> +config VDPA_USER
> >>> +     tristate "VDUSE (vDPA Device in Userspace) support"
> >>> +     depends on EVENTFD && MMU && HAS_DMA
> >>> +     select DMA_OPS
> >>> +     select VHOST_IOTLB
> >>> +     select IOMMU_IOVA
> >>> +     help
> >>> +       With VDUSE it is possible to emulate a vDPA Device
> >>> +       in a userspace program.
> >>> +
> >>>    config IFCVF
> >>>        tristate "Intel IFC VF vDPA driver"
> >>>        depends on PCI_MSI
> >>> diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile
> >>> index 67fe7f3d6943..f02ebed33f19 100644
> >>> --- a/drivers/vdpa/Makefile
> >>> +++ b/drivers/vdpa/Makefile
> >>> @@ -1,6 +1,7 @@
> >>>    # SPDX-License-Identifier: GPL-2.0
> >>>    obj-$(CONFIG_VDPA) += vdpa.o
> >>>    obj-$(CONFIG_VDPA_SIM) += vdpa_sim/
> >>> +obj-$(CONFIG_VDPA_USER) += vdpa_user/
> >>>    obj-$(CONFIG_IFCVF)    += ifcvf/
> >>>    obj-$(CONFIG_MLX5_VDPA) += mlx5/
> >>>    obj-$(CONFIG_VP_VDPA)    += virtio_pci/
> >>> diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile
> >>> new file mode 100644
> >>> index 000000000000..260e0b26af99
> >>> --- /dev/null
> >>> +++ b/drivers/vdpa/vdpa_user/Makefile
> >>> @@ -0,0 +1,5 @@
> >>> +# SPDX-License-Identifier: GPL-2.0
> >>> +
> >>> +vduse-y := vduse_dev.o iova_domain.o
> >>> +
> >>> +obj-$(CONFIG_VDPA_USER) += vduse.o
> >>> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> >>> new file mode 100644
> >>> index 000000000000..5271cbd15e28
> >>> --- /dev/null
> >>> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> >>> @@ -0,0 +1,1453 @@
> >>> +// SPDX-License-Identifier: GPL-2.0-only
> >>> +/*
> >>> + * VDUSE: vDPA Device in Userspace
> >>> + *
> >>> + * Copyright (C) 2020-2021 Bytedance Inc. and/or its affiliates. All rights reserved.
> >>> + *
> >>> + * Author: Xie Yongji <[e-mail]>
> >>> + *
> >>> + */
> >>> +
> >>> +#include <linux/init.h>
> >>> +#include <linux/module.h>
> >>> +#include <linux/cdev.h>
> >>> +#include <linux/device.h>
> >>> +#include <linux/eventfd.h>
> >>> +#include <linux/slab.h>
> >>> +#include <linux/wait.h>
> >>> +#include <linux/dma-map-ops.h>
> >>> +#include <linux/poll.h>
> >>> +#include <linux/file.h>
> >>> +#include <linux/uio.h>
> >>> +#include <linux/vdpa.h>
> >>> +#include <linux/nospec.h>
> >>> +#include <uapi/linux/vduse.h>
> >>> +#include <uapi/linux/vdpa.h>
> >>> +#include <uapi/linux/virtio_config.h>
> >>> +#include <uapi/linux/virtio_ids.h>
> >>> +#include <uapi/linux/virtio_blk.h>
> >>> +#include <linux/mod_devicetable.h>
> >>> +
> >>> +#include "iova_domain.h"
> >>> +
> >>> +#define DRV_AUTHOR   "Yongji Xie <[e-mail]>"
> >>> +#define DRV_DESC     "vDPA Device in Userspace"
> >>> +#define DRV_LICENSE  "GPL v2"
> >>> +
> >>> +#define VDUSE_DEV_MAX (1U << MINORBITS)
> >>> +#define VDUSE_MAX_BOUNCE_SIZE (64 * 1024 * 1024)
> >>> +#define VDUSE_IOVA_SIZE (128 * 1024 * 1024)
> >>> +#define VDUSE_REQUEST_TIMEOUT 30
> >>> +
> >>> +struct vduse_virtqueue {
> >>> +     u16 index;
> >>> +     u32 num;
> >>> +     u32 avail_idx;
> >>> +     u64 desc_addr;
> >>> +     u64 driver_addr;
> >>> +     u64 device_addr;
> >>> +     bool ready;
> >>> +     bool kicked;
> >>> +     spinlock_t kick_lock;
> >>> +     spinlock_t irq_lock;
> >>> +     struct eventfd_ctx *kickfd;
> >>> +     struct vdpa_callback cb;
> >>> +     struct work_struct inject;
> >>> +};
> >>> +
> >>> +struct vduse_dev;
> >>> +
> >>> +struct vduse_vdpa {
> >>> +     struct vdpa_device vdpa;
> >>> +     struct vduse_dev *dev;
> >>> +};
> >>> +
> >>> +struct vduse_dev {
> >>> +     struct vduse_vdpa *vdev;
> >>> +     struct device *dev;
> >>> +     struct vduse_virtqueue *vqs;
> >>> +     struct vduse_iova_domain *domain;
> >>> +     char *name;
> >>> +     struct mutex lock;
> >>> +     spinlock_t msg_lock;
> >>> +     u64 msg_unique;
> >>> +     wait_queue_head_t waitq;
> >>> +     struct list_head send_list;
> >>> +     struct list_head recv_list;
> >>> +     struct vdpa_callback config_cb;
> >>> +     struct work_struct inject;
> >>> +     spinlock_t irq_lock;
> >>> +     int minor;
> >>> +     bool connected;
> >>> +     bool started;
> >>> +     u64 api_version;
> >>> +     u64 user_features;
> >>
> >> Let's use device_features.
> >>
> > OK.
> >
> >>> +     u64 features;
> >>
> >> And driver features.
> >>
> > OK.
> >
> >>> +     u32 device_id;
> >>> +     u32 vendor_id;
> >>> +     u32 generation;
> >>> +     u32 config_size;
> >>> +     void *config;
> >>> +     u8 status;
> >>> +     u16 vq_size_max;
> >>> +     u32 vq_num;
> >>> +     u32 vq_align;
> >>> +};
> >>> +
> >>> +struct vduse_dev_msg {
> >>> +     struct vduse_dev_request req;
> >>> +     struct vduse_dev_response resp;
> >>> +     struct list_head list;
> >>> +     wait_queue_head_t waitq;
> >>> +     bool completed;
> >>> +};
> >>> +
> >>> +struct vduse_control {
> >>> +     u64 api_version;
> >>> +};
> >>> +
> >>> +static DEFINE_MUTEX(vduse_lock);
> >>> +static DEFINE_IDR(vduse_idr);
> >>> +
> >>> +static dev_t vduse_major;
> >>> +static struct class *vduse_class;
> >>> +static struct cdev vduse_ctrl_cdev;
> >>> +static struct cdev vduse_cdev;
> >>> +static struct workqueue_struct *vduse_irq_wq;
> >>> +
> >>> +static u32 allowed_device_id[] = {
> >>> +     VIRTIO_ID_BLOCK,
> >>> +};
> >>> +
> >>> +static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa)
> >>> +{
> >>> +     struct vduse_vdpa *vdev = container_of(vdpa, struct vduse_vdpa, vdpa);
> >>> +
> >>> +     return vdev->dev;
> >>> +}
> >>> +
> >>> +static inline struct vduse_dev *dev_to_vduse(struct device *dev)
> >>> +{
> >>> +     struct vdpa_device *vdpa = dev_to_vdpa(dev);
> >>> +
> >>> +     return vdpa_to_vduse(vdpa);
> >>> +}
> >>> +
> >>> +static struct vduse_dev_msg *vduse_find_msg(struct list_head *head,
> >>> +                                         uint32_t request_id)
> >>> +{
> >>> +     struct vduse_dev_msg *msg;
> >>> +
> >>> +     list_for_each_entry(msg, head, list) {
> >>> +             if (msg->req.request_id == request_id) {
> >>> +                     list_del(&msg->list);
> >>> +                     return msg;
> >>> +             }
> >>> +     }
> >>> +
> >>> +     return NULL;
> >>> +}
> >>> +
> >>> +static struct vduse_dev_msg *vduse_dequeue_msg(struct list_head *head)
> >>> +{
> >>> +     struct vduse_dev_msg *msg = NULL;
> >>> +
> >>> +     if (!list_empty(head)) {
> >>> +             msg = list_first_entry(head, struct vduse_dev_msg, list);
> >>> +             list_del(&msg->list);
> >>> +     }
> >>> +
> >>> +     return msg;
> >>> +}
> >>> +
> >>> +static void vduse_enqueue_msg(struct list_head *head,
> >>> +                           struct vduse_dev_msg *msg)
> >>> +{
> >>> +     list_add_tail(&msg->list, head);
> >>> +}
> >>> +
> >>> +static int vduse_dev_msg_send(struct vduse_dev *dev,
> >>> +                           struct vduse_dev_msg *msg, bool no_reply)
> >>> +{
> >>
> >> It looks to me the only user for no_reply=true is the dataplane start. I
> >> wonder no_reply is really needed consider we have switched to use
> >> wait_event_killable_timeout().
> >>
> > Do we need to handle the error in this case if we remove the no_reply
> > flag. Print a warning message?
>
>
> See below.
>
>
> >
> >> In another way, no_reply is false for vq state synchronization and IOTLB
> >> updating. I wonder if we can simply use no_reply = true for them.
> >>
> > Looks like we can't, e.g. we need to get a reply from userspace for vq state.
>
>
> Right.
>
>
> >
> >>> +     init_waitqueue_head(&msg->waitq);
> >>> +     spin_lock(&dev->msg_lock);
> >>> +     msg->req.request_id = dev->msg_unique++;
> >>> +     vduse_enqueue_msg(&dev->send_list, msg);
> >>> +     wake_up(&dev->waitq);
> >>> +     spin_unlock(&dev->msg_lock);
> >>> +     if (no_reply)
> >>> +             return 0;
> >>> +
> >>> +     wait_event_killable_timeout(msg->waitq, msg->completed,
> >>> +                                 VDUSE_REQUEST_TIMEOUT * HZ);
> >>> +     spin_lock(&dev->msg_lock);
> >>> +     if (!msg->completed) {
> >>> +             list_del(&msg->list);
> >>> +             msg->resp.result = VDUSE_REQ_RESULT_FAILED;
> >>> +     }
> >>> +     spin_unlock(&dev->msg_lock);
> >>> +
> >>> +     return (msg->resp.result == VDUSE_REQ_RESULT_OK) ? 0 : -EIO;
> >>
> >> Do we need to serialize the check by protecting it with the spinlock above?
> >>
> > Good point.
> >
> >>> +}
> >>> +
> >>> +static void vduse_dev_msg_cleanup(struct vduse_dev *dev)
> >>> +{
> >>> +     struct vduse_dev_msg *msg;
> >>> +
> >>> +     spin_lock(&dev->msg_lock);
> >>> +     while ((msg = vduse_dequeue_msg(&dev->send_list))) {
> >>> +             if (msg->req.flags & VDUSE_REQ_FLAGS_NO_REPLY)
> >>> +                     kfree(msg);
> >>> +             else
> >>> +                     vduse_enqueue_msg(&dev->recv_list, msg);
> >>> +     }
> >>> +     while ((msg = vduse_dequeue_msg(&dev->recv_list))) {
> >>> +             msg->resp.result = VDUSE_REQ_RESULT_FAILED;
> >>> +             msg->completed = 1;
> >>> +             wake_up(&msg->waitq);
> >>> +     }
> >>> +     spin_unlock(&dev->msg_lock);
> >>> +}
> >>> +
> >>> +static void vduse_dev_start_dataplane(struct vduse_dev *dev)
> >>> +{
> >>> +     struct vduse_dev_msg *msg = kzalloc(sizeof(*msg),
> >>> +                                         GFP_KERNEL | __GFP_NOFAIL);
> >>> +
> >>> +     msg->req.type = VDUSE_START_DATAPLANE;
> >>> +     msg->req.flags |= VDUSE_REQ_FLAGS_NO_REPLY;
> >>> +     vduse_dev_msg_send(dev, msg, true);
> >>> +}
> >>> +
> >>> +static void vduse_dev_stop_dataplane(struct vduse_dev *dev)
> >>> +{
> >>> +     struct vduse_dev_msg *msg = kzalloc(sizeof(*msg),
> >>> +                                         GFP_KERNEL | __GFP_NOFAIL);
> >>> +
> >>> +     msg->req.type = VDUSE_STOP_DATAPLANE;
> >>> +     msg->req.flags |= VDUSE_REQ_FLAGS_NO_REPLY;
> >>
> >> Can we simply use this flag instead of introducing a new parameter
> >> (no_reply) in vduse_dev_msg_send()?
> >>
> > Looks good to me.
> >
> >>> +     vduse_dev_msg_send(dev, msg, true);
> >>> +}
> >>> +
> >>> +static int vduse_dev_get_vq_state(struct vduse_dev *dev,
> >>> +                               struct vduse_virtqueue *vq,
> >>> +                               struct vdpa_vq_state *state)
> >>> +{
> >>> +     struct vduse_dev_msg msg = { 0 };
> >>> +     int ret;
> >>
> >> Note that I post a series that implement the packed virtqueue support:
> >>
> >> https://lists.linuxfoundation.org/pipermail/virtualization/2021-June/054501.html
> >>
> >> So this patch needs to be updated as well.
> >>
> > Will do it.
> >
> >>> +
> >>> +     msg.req.type = VDUSE_GET_VQ_STATE;
> >>> +     msg.req.vq_state.index = vq->index;
> >>> +
> >>> +     ret = vduse_dev_msg_send(dev, &msg, false);
> >>> +     if (ret)
> >>> +             return ret;
> >>> +
> >>> +     state->avail_index = msg.resp.vq_state.avail_idx;
> >>> +     return 0;
> >>> +}
> >>> +
> >>> +static int vduse_dev_update_iotlb(struct vduse_dev *dev,
> >>> +                             u64 start, u64 last)
> >>> +{
> >>> +     struct vduse_dev_msg msg = { 0 };
> >>> +
> >>> +     if (last < start)
> >>> +             return -EINVAL;
> >>> +
> >>> +     msg.req.type = VDUSE_UPDATE_IOTLB;
> >>> +     msg.req.iova.start = start;
> >>> +     msg.req.iova.last = last;
> >>> +
> >>> +     return vduse_dev_msg_send(dev, &msg, false);
> >>> +}
> >>> +
> >>> +static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to)
> >>> +{
> >>> +     struct file *file = iocb->ki_filp;
> >>> +     struct vduse_dev *dev = file->private_data;
> >>> +     struct vduse_dev_msg *msg;
> >>> +     int size = sizeof(struct vduse_dev_request);
> >>> +     ssize_t ret;
> >>> +
> >>> +     if (iov_iter_count(to) < size)
> >>> +             return -EINVAL;
> >>> +
> >>> +     spin_lock(&dev->msg_lock);
> >>> +     while (1) {
> >>> +             msg = vduse_dequeue_msg(&dev->send_list);
> >>> +             if (msg)
> >>> +                     break;
> >>> +
> >>> +             ret = -EAGAIN;
> >>> +             if (file->f_flags & O_NONBLOCK)
> >>> +                     goto unlock;
> >>> +
> >>> +             spin_unlock(&dev->msg_lock);
> >>> +             ret = wait_event_interruptible_exclusive(dev->waitq,
> >>> +                                     !list_empty(&dev->send_list));
> >>> +             if (ret)
> >>> +                     return ret;
> >>> +
> >>> +             spin_lock(&dev->msg_lock);
> >>> +     }
> >>> +     spin_unlock(&dev->msg_lock);
> >>> +     ret = copy_to_iter(&msg->req, size, to);
> >>> +     spin_lock(&dev->msg_lock);
> >>> +     if (ret != size) {
> >>> +             ret = -EFAULT;
> >>> +             vduse_enqueue_msg(&dev->send_list, msg);
> >>> +             goto unlock;
> >>> +     }
> >>> +     if (msg->req.flags & VDUSE_REQ_FLAGS_NO_REPLY)
> >>> +             kfree(msg);
> >>> +     else
> >>> +             vduse_enqueue_msg(&dev->recv_list, msg);
> >>> +unlock:
> >>> +     spin_unlock(&dev->msg_lock);
> >>> +
> >>> +     return ret;
> >>> +}
> >>> +
> >>> +static ssize_t vduse_dev_write_iter(struct kiocb *iocb, struct iov_iter *from)
> >>> +{
> >>> +     struct file *file = iocb->ki_filp;
> >>> +     struct vduse_dev *dev = file->private_data;
> >>> +     struct vduse_dev_response resp;
> >>> +     struct vduse_dev_msg *msg;
> >>> +     size_t ret;
> >>> +
> >>> +     ret = copy_from_iter(&resp, sizeof(resp), from);
> >>> +     if (ret != sizeof(resp))
> >>> +             return -EINVAL;
> >>> +
> >>> +     spin_lock(&dev->msg_lock);
> >>> +     msg = vduse_find_msg(&dev->recv_list, resp.request_id);
> >>> +     if (!msg) {
> >>> +             ret = -ENOENT;
> >>> +             goto unlock;
> >>> +     }
> >>> +
> >>> +     memcpy(&msg->resp, &resp, sizeof(resp));
> >>> +     msg->completed = 1;
> >>> +     wake_up(&msg->waitq);
> >>> +unlock:
> >>> +     spin_unlock(&dev->msg_lock);
> >>> +
> >>> +     return ret;
> >>> +}
> >>> +
> >>> +static __poll_t vduse_dev_poll(struct file *file, poll_table *wait)
> >>> +{
> >>> +     struct vduse_dev *dev = file->private_data;
> >>> +     __poll_t mask = 0;
> >>> +
> >>> +     poll_wait(file, &dev->waitq, wait);
> >>> +
> >>> +     if (!list_empty(&dev->send_list))
> >>> +             mask |= EPOLLIN | EPOLLRDNORM;
> >>> +     if (!list_empty(&dev->recv_list))
> >>> +             mask |= EPOLLOUT | EPOLLWRNORM;
> >>> +
> >>> +     return mask;
> >>> +}
> >>> +
> >>> +static void vduse_dev_reset(struct vduse_dev *dev)
> >>> +{
> >>> +     int i;
> >>> +     struct vduse_iova_domain *domain = dev->domain;
> >>> +
> >>> +     /* The coherent mappings are handled in vduse_dev_free_coherent() */
> >>> +     if (domain->bounce_map)
> >>> +             vduse_domain_reset_bounce_map(domain);
> >>> +
> >>> +     dev->features = 0;
> >>> +     dev->generation++;
> >>> +     spin_lock(&dev->irq_lock);
> >>> +     dev->config_cb.callback = NULL;
> >>> +     dev->config_cb.private = NULL;
> >>> +     spin_unlock(&dev->irq_lock);
> >>> +
> >>> +     for (i = 0; i < dev->vq_num; i++) {
> >>> +             struct vduse_virtqueue *vq = &dev->vqs[i];
> >>> +
> >>> +             vq->ready = false;
> >>> +             vq->desc_addr = 0;
> >>> +             vq->driver_addr = 0;
> >>> +             vq->device_addr = 0;
> >>> +             vq->avail_idx = 0;
> >>> +             vq->num = 0;
> >>> +
> >>> +             spin_lock(&vq->kick_lock);
> >>> +             vq->kicked = false;
> >>> +             if (vq->kickfd)
> >>> +                     eventfd_ctx_put(vq->kickfd);
> >>> +             vq->kickfd = NULL;
> >>> +             spin_unlock(&vq->kick_lock);
> >>> +
> >>> +             spin_lock(&vq->irq_lock);
> >>> +             vq->cb.callback = NULL;
> >>> +             vq->cb.private = NULL;
> >>> +             spin_unlock(&vq->irq_lock);
> >>> +     }
> >>> +}
> >>> +
> >>> +static int vduse_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 idx,
> >>> +                             u64 desc_area, u64 driver_area,
> >>> +                             u64 device_area)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> >>> +
> >>> +     vq->desc_addr = desc_area;
> >>> +     vq->driver_addr = driver_area;
> >>> +     vq->device_addr = device_area;
> >>> +
> >>> +     return 0;
> >>> +}
> >>> +
> >>> +static void vduse_vdpa_kick_vq(struct vdpa_device *vdpa, u16 idx)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> >>> +
> >>> +     spin_lock(&vq->kick_lock);
> >>> +     if (!vq->ready)
> >>> +             goto unlock;
> >>> +
> >>> +     if (vq->kickfd)
> >>> +             eventfd_signal(vq->kickfd, 1);
> >>> +     else
> >>> +             vq->kicked = true;
> >>> +unlock:
> >>> +     spin_unlock(&vq->kick_lock);
> >>> +}
> >>> +
> >>> +static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,
> >>> +                           struct vdpa_callback *cb)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> >>> +
> >>> +     spin_lock(&vq->irq_lock);
> >>> +     vq->cb.callback = cb->callback;
> >>> +     vq->cb.private = cb->private;
> >>> +     spin_unlock(&vq->irq_lock);
> >>> +}
> >>> +
> >>> +static void vduse_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> >>> +
> >>> +     vq->num = num;
> >>> +}
> >>> +
> >>> +static void vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa,
> >>> +                                     u16 idx, bool ready)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> >>> +
> >>> +     vq->ready = ready;
> >>> +}
> >>> +
> >>> +static bool vduse_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 idx)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> >>> +
> >>> +     return vq->ready;
> >>> +}
> >>> +
> >>> +static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,
> >>> +                             const struct vdpa_vq_state *state)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> >>> +
> >>> +     vq->avail_idx = state->avail_index;
> >>> +     return 0;
> >>> +}
> >>> +
> >>> +static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
> >>> +                             struct vdpa_vq_state *state)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];
> >>> +
> >>> +     return vduse_dev_get_vq_state(dev, vq, state);
> >>> +}
> >>> +
> >>> +static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +
> >>> +     return dev->vq_align;
> >>> +}
> >>> +
> >>> +static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +
> >>> +     return dev->user_features;
> >>> +}
> >>> +
> >>> +static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +
> >>> +     dev->features = features;
> >>> +     return 0;
> >>> +}
> >>> +
> >>> +static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,
> >>> +                               struct vdpa_callback *cb)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +
> >>> +     spin_lock(&dev->irq_lock);
> >>> +     dev->config_cb.callback = cb->callback;
> >>> +     dev->config_cb.private = cb->private;
> >>> +     spin_unlock(&dev->irq_lock);
> >>> +}
> >>> +
> >>> +static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +
> >>> +     return dev->vq_size_max;
> >>> +}
> >>> +
> >>> +static u32 vduse_vdpa_get_device_id(struct vdpa_device *vdpa)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +
> >>> +     return dev->device_id;
> >>> +}
> >>> +
> >>> +static u32 vduse_vdpa_get_vendor_id(struct vdpa_device *vdpa)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +
> >>> +     return dev->vendor_id;
> >>> +}
> >>> +
> >>> +static u8 vduse_vdpa_get_status(struct vdpa_device *vdpa)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +
> >>> +     return dev->status;
> >>> +}
> >>> +
> >>> +static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +     bool started = !!(status & VIRTIO_CONFIG_S_DRIVER_OK);
> >>> +
> >>> +     dev->status = status;
> >>> +
> >>> +     if (dev->started == started)
> >>> +             return;
> >>
> >> If we check dev->status == status, (or only check the DRIVER_OK bit)
> >> then there's no need to introduce an extra dev->started.
> >>
> > Will do it.
> >
> >>> +
> >>> +     dev->started = started;
> >>> +     if (dev->started) {
> >>> +             vduse_dev_start_dataplane(dev);
> >>> +     } else {
> >>> +             vduse_dev_reset(dev);
> >>> +             vduse_dev_stop_dataplane(dev);
> >>
> >> I wonder if no_reply work for the case of vhost-vdpa. For virtio-vDPA,
> >> we have bouncing buffers so it's harmless if usersapce dataplane keeps
> >> performing read/write. For vhost-vDPA we don't have such stuffs.
> >>
> > OK. So it still needs to be synchronized here. If so, how to handle
> > the error? Looks like printing a warning message should be enough.
>
>
> We need fix a way to propagate the error to the userspace.
>
> E.g if we want to stop the deivce, we will delay the status reset until
> we get respose from the userspace?
>

I didn't get how to delay the status reset. And should it be a DoS
that we want to fix if the userspace doesn't give a response forever?

>
> >
> >>> +     }
> >>> +}
> >>> +
> >>> +static size_t vduse_vdpa_get_config_size(struct vdpa_device *vdpa)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +
> >>> +     return dev->config_size;
> >>> +}
> >>> +
> >>> +static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,
> >>> +                               void *buf, unsigned int len)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +
> >>> +     memcpy(buf, dev->config + offset, len);
> >>> +}
> >>> +
> >>> +static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,
> >>> +                     const void *buf, unsigned int len)
> >>> +{
> >>> +     /* Now we only support read-only configuration space */
> >>> +}
> >>> +
> >>> +static u32 vduse_vdpa_get_generation(struct vdpa_device *vdpa)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +
> >>> +     return dev->generation;
> >>> +}
> >>> +
> >>> +static int vduse_vdpa_set_map(struct vdpa_device *vdpa,
> >>> +                             struct vhost_iotlb *iotlb)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +     int ret;
> >>> +
> >>> +     ret = vduse_domain_set_map(dev->domain, iotlb);
> >>> +     if (ret)
> >>> +             return ret;
> >>> +
> >>> +     ret = vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
> >>> +     if (ret) {
> >>> +             vduse_domain_clear_map(dev->domain, iotlb);
> >>> +             return ret;
> >>> +     }
> >>> +
> >>> +     return 0;
> >>> +}
> >>> +
> >>> +static void vduse_vdpa_free(struct vdpa_device *vdpa)
> >>> +{
> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> >>> +
> >>> +     dev->vdev = NULL;
> >>> +}
> >>> +
> >>> +static const struct vdpa_config_ops vduse_vdpa_config_ops = {
> >>> +     .set_vq_address         = vduse_vdpa_set_vq_address,
> >>> +     .kick_vq                = vduse_vdpa_kick_vq,
> >>> +     .set_vq_cb              = vduse_vdpa_set_vq_cb,
> >>> +     .set_vq_num             = vduse_vdpa_set_vq_num,
> >>> +     .set_vq_ready           = vduse_vdpa_set_vq_ready,
> >>> +     .get_vq_ready           = vduse_vdpa_get_vq_ready,
> >>> +     .set_vq_state           = vduse_vdpa_set_vq_state,
> >>> +     .get_vq_state           = vduse_vdpa_get_vq_state,
> >>> +     .get_vq_align           = vduse_vdpa_get_vq_align,
> >>> +     .get_features           = vduse_vdpa_get_features,
> >>> +     .set_features           = vduse_vdpa_set_features,
> >>> +     .set_config_cb          = vduse_vdpa_set_config_cb,
> >>> +     .get_vq_num_max         = vduse_vdpa_get_vq_num_max,
> >>> +     .get_device_id          = vduse_vdpa_get_device_id,
> >>> +     .get_vendor_id          = vduse_vdpa_get_vendor_id,
> >>> +     .get_status             = vduse_vdpa_get_status,
> >>> +     .set_status             = vduse_vdpa_set_status,
> >>> +     .get_config_size        = vduse_vdpa_get_config_size,
> >>> +     .get_config             = vduse_vdpa_get_config,
> >>> +     .set_config             = vduse_vdpa_set_config,
> >>> +     .get_generation         = vduse_vdpa_get_generation,
> >>> +     .set_map                = vduse_vdpa_set_map,
> >>> +     .free                   = vduse_vdpa_free,
> >>> +};
> >>> +
> >>> +static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,
> >>> +                                  unsigned long offset, size_t size,
> >>> +                                  enum dma_data_direction dir,
> >>> +                                  unsigned long attrs)
> >>> +{
> >>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
> >>> +     struct vduse_iova_domain *domain = vdev->domain;
> >>> +
> >>> +     return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
> >>> +}
> >>> +
> >>> +static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,
> >>> +                             size_t size, enum dma_data_direction dir,
> >>> +                             unsigned long attrs)
> >>> +{
> >>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
> >>> +     struct vduse_iova_domain *domain = vdev->domain;
> >>> +
> >>> +     return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
> >>> +}
> >>> +
> >>> +static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,
> >>> +                                     dma_addr_t *dma_addr, gfp_t flag,
> >>> +                                     unsigned long attrs)
> >>> +{
> >>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
> >>> +     struct vduse_iova_domain *domain = vdev->domain;
> >>> +     unsigned long iova;
> >>> +     void *addr;
> >>> +
> >>> +     *dma_addr = DMA_MAPPING_ERROR;
> >>> +     addr = vduse_domain_alloc_coherent(domain, size,
> >>> +                             (dma_addr_t *)&iova, flag, attrs);
> >>> +     if (!addr)
> >>> +             return NULL;
> >>> +
> >>> +     *dma_addr = (dma_addr_t)iova;
> >>> +
> >>> +     return addr;
> >>> +}
> >>> +
> >>> +static void vduse_dev_free_coherent(struct device *dev, size_t size,
> >>> +                                     void *vaddr, dma_addr_t dma_addr,
> >>> +                                     unsigned long attrs)
> >>> +{
> >>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
> >>> +     struct vduse_iova_domain *domain = vdev->domain;
> >>> +
> >>> +     vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
> >>> +}
> >>> +
> >>> +static size_t vduse_dev_max_mapping_size(struct device *dev)
> >>> +{
> >>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
> >>> +     struct vduse_iova_domain *domain = vdev->domain;
> >>> +
> >>> +     return domain->bounce_size;
> >>> +}
> >>> +
> >>> +static const struct dma_map_ops vduse_dev_dma_ops = {
> >>> +     .map_page = vduse_dev_map_page,
> >>> +     .unmap_page = vduse_dev_unmap_page,
> >>> +     .alloc = vduse_dev_alloc_coherent,
> >>> +     .free = vduse_dev_free_coherent,
> >>> +     .max_mapping_size = vduse_dev_max_mapping_size,
> >>> +};
> >>> +
> >>> +static unsigned int perm_to_file_flags(u8 perm)
> >>> +{
> >>> +     unsigned int flags = 0;
> >>> +
> >>> +     switch (perm) {
> >>> +     case VDUSE_ACCESS_WO:
> >>> +             flags |= O_WRONLY;
> >>> +             break;
> >>> +     case VDUSE_ACCESS_RO:
> >>> +             flags |= O_RDONLY;
> >>> +             break;
> >>> +     case VDUSE_ACCESS_RW:
> >>> +             flags |= O_RDWR;
> >>> +             break;
> >>> +     default:
> >>> +             WARN(1, "invalidate vhost IOTLB permission\n");
> >>> +             break;
> >>> +     }
> >>> +
> >>> +     return flags;
> >>> +}
> >>> +
> >>> +static int vduse_kickfd_setup(struct vduse_dev *dev,
> >>> +                     struct vduse_vq_eventfd *eventfd)
> >>> +{
> >>> +     struct eventfd_ctx *ctx = NULL;
> >>> +     struct vduse_virtqueue *vq;
> >>> +     u32 index;
> >>> +
> >>> +     if (eventfd->index >= dev->vq_num)
> >>> +             return -EINVAL;
> >>> +
> >>> +     index = array_index_nospec(eventfd->index, dev->vq_num);
> >>> +     vq = &dev->vqs[index];
> >>> +     if (eventfd->fd >= 0) {
> >>> +             ctx = eventfd_ctx_fdget(eventfd->fd);
> >>> +             if (IS_ERR(ctx))
> >>> +                     return PTR_ERR(ctx);
> >>> +     } else if (eventfd->fd != VDUSE_EVENTFD_DEASSIGN)
> >>> +             return 0;
> >>> +
> >>> +     spin_lock(&vq->kick_lock);
> >>> +     if (vq->kickfd)
> >>> +             eventfd_ctx_put(vq->kickfd);
> >>> +     vq->kickfd = ctx;
> >>> +     if (vq->ready && vq->kicked && vq->kickfd) {
> >>> +             eventfd_signal(vq->kickfd, 1);
> >>> +             vq->kicked = false;
> >>> +     }
> >>> +     spin_unlock(&vq->kick_lock);
> >>> +
> >>> +     return 0;
> >>> +}
> >>> +
> >>> +static void vduse_dev_irq_inject(struct work_struct *work)
> >>> +{
> >>> +     struct vduse_dev *dev = container_of(work, struct vduse_dev, inject);
> >>> +
> >>> +     spin_lock_irq(&dev->irq_lock);
> >>> +     if (dev->config_cb.callback)
> >>> +             dev->config_cb.callback(dev->config_cb.private);
> >>> +     spin_unlock_irq(&dev->irq_lock);
> >>> +}
> >>> +
> >>> +static void vduse_vq_irq_inject(struct work_struct *work)
> >>> +{
> >>> +     struct vduse_virtqueue *vq = container_of(work,
> >>> +                                     struct vduse_virtqueue, inject);
> >>> +
> >>> +     spin_lock_irq(&vq->irq_lock);
> >>> +     if (vq->ready && vq->cb.callback)
> >>> +             vq->cb.callback(vq->cb.private);
> >>> +     spin_unlock_irq(&vq->irq_lock);
> >>> +}
> >>> +
> >>> +static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
> >>> +                         unsigned long arg)
> >>> +{
> >>> +     struct vduse_dev *dev = file->private_data;
> >>> +     void __user *argp = (void __user *)arg;
> >>> +     int ret;
> >>> +
> >>> +     switch (cmd) {
> >>> +     case VDUSE_IOTLB_GET_FD: {
> >>> +             struct vduse_iotlb_entry entry;
> >>> +             struct vhost_iotlb_map *map;
> >>> +             struct vdpa_map_file *map_file;
> >>> +             struct vduse_iova_domain *domain = dev->domain;
> >>> +             struct file *f = NULL;
> >>> +
> >>> +             ret = -EFAULT;
> >>> +             if (copy_from_user(&entry, argp, sizeof(entry)))
> >>> +                     break;
> >>> +
> >>> +             ret = -EINVAL;
> >>> +             if (entry.start > entry.last)
> >>> +                     break;
> >>> +
> >>> +             spin_lock(&domain->iotlb_lock);
> >>> +             map = vhost_iotlb_itree_first(domain->iotlb,
> >>> +                                           entry.start, entry.last);
> >>> +             if (map) {
> >>> +                     map_file = (struct vdpa_map_file *)map->opaque;
> >>> +                     f = get_file(map_file->file);
> >>> +                     entry.offset = map_file->offset;
> >>> +                     entry.start = map->start;
> >>> +                     entry.last = map->last;
> >>> +                     entry.perm = map->perm;
> >>> +             }
> >>> +             spin_unlock(&domain->iotlb_lock);
> >>> +             ret = -EINVAL;
> >>> +             if (!f)
> >>> +                     break;
> >>> +
> >>> +             ret = -EFAULT;
> >>> +             if (copy_to_user(argp, &entry, sizeof(entry))) {
> >>> +                     fput(f);
> >>> +                     break;
> >>> +             }
> >>> +             ret = receive_fd(f, perm_to_file_flags(entry.perm));
> >>> +             fput(f);
> >>> +             break;
> >>> +     }
> >>> +     case VDUSE_DEV_GET_FEATURES:
> >>> +             ret = put_user(dev->features, (u64 __user *)argp);
> >>> +             break;
> >>> +     case VDUSE_DEV_UPDATE_CONFIG: {
> >>> +             struct vduse_config_update config;
> >>> +             unsigned long size = offsetof(struct vduse_config_update,
> >>> +                                           buffer);
> >>> +
> >>> +             ret = -EFAULT;
> >>> +             if (copy_from_user(&config, argp, size))
> >>> +                     break;
> >>> +
> >>> +             ret = -EINVAL;
> >>> +             if (config.length == 0 ||
> >>> +                 config.length > dev->config_size - config.offset)
> >>> +                     break;
> >>> +
> >>> +             ret = -EFAULT;
> >>> +             if (copy_from_user(dev->config + config.offset, argp + size,
> >>> +                                config.length))
> >>> +                     break;
> >>> +
> >>> +             ret = 0;
> >>> +             queue_work(vduse_irq_wq, &dev->inject);
> >>
> >> I wonder if it's better to separate config interrupt out of config
> >> update or we need document this.
> >>
> > I have documented it in the docs. Looks like a config update should be
> > always followed by a config interrupt. I didn't find a case that uses
> > them separately.
>
>
> The uAPI doesn't prevent us from the following scenario:
>
> update_config(mac[0], ..);
> update_config(max[1], ..);
>
> So it looks to me it's better to separate the config interrupt from the
> config updating.
>

Fine.

>
> >
> >>> +             break;
> >>> +     }
> >>> +     case VDUSE_VQ_GET_INFO: {
> >>
> >> Do we need to limit this only when DRIVER_OK is set?
> >>
> > Any reason to add this limitation?
>
>
> Otherwise the vq is not fully initialized, e.g the desc_addr might not
> be correct.
>

The vq_info->ready can be used to tell userspace whether the vq is
initialized or not.

Thanks,
Yongji

Jason Wang June 22, 2021, 7:49 a.m. UTC | #5

在 2021/6/22 下午3:22, Yongji Xie 写道:
>> We need fix a way to propagate the error to the userspace.
>>
>> E.g if we want to stop the deivce, we will delay the status reset until
>> we get respose from the userspace?
>>
> I didn't get how to delay the status reset. And should it be a DoS
> that we want to fix if the userspace doesn't give a response forever?


You're right. So let's make set_status() can fail first, then propagate 
its failure via VHOST_VDPA_SET_STATUS.


>
>>>>> +     }
>>>>> +}
>>>>> +
>>>>> +static size_t vduse_vdpa_get_config_size(struct vdpa_device *vdpa)
>>>>> +{
>>>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>>>> +
>>>>> +     return dev->config_size;
>>>>> +}
>>>>> +
>>>>> +static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,
>>>>> +                               void *buf, unsigned int len)
>>>>> +{
>>>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>>>> +
>>>>> +     memcpy(buf, dev->config + offset, len);
>>>>> +}
>>>>> +
>>>>> +static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,
>>>>> +                     const void *buf, unsigned int len)
>>>>> +{
>>>>> +     /* Now we only support read-only configuration space */
>>>>> +}
>>>>> +
>>>>> +static u32 vduse_vdpa_get_generation(struct vdpa_device *vdpa)
>>>>> +{
>>>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>>>> +
>>>>> +     return dev->generation;
>>>>> +}
>>>>> +
>>>>> +static int vduse_vdpa_set_map(struct vdpa_device *vdpa,
>>>>> +                             struct vhost_iotlb *iotlb)
>>>>> +{
>>>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>>>> +     int ret;
>>>>> +
>>>>> +     ret = vduse_domain_set_map(dev->domain, iotlb);
>>>>> +     if (ret)
>>>>> +             return ret;
>>>>> +
>>>>> +     ret = vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
>>>>> +     if (ret) {
>>>>> +             vduse_domain_clear_map(dev->domain, iotlb);
>>>>> +             return ret;
>>>>> +     }
>>>>> +
>>>>> +     return 0;
>>>>> +}
>>>>> +
>>>>> +static void vduse_vdpa_free(struct vdpa_device *vdpa)
>>>>> +{
>>>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>>>> +
>>>>> +     dev->vdev = NULL;
>>>>> +}
>>>>> +
>>>>> +static const struct vdpa_config_ops vduse_vdpa_config_ops = {
>>>>> +     .set_vq_address         = vduse_vdpa_set_vq_address,
>>>>> +     .kick_vq                = vduse_vdpa_kick_vq,
>>>>> +     .set_vq_cb              = vduse_vdpa_set_vq_cb,
>>>>> +     .set_vq_num             = vduse_vdpa_set_vq_num,
>>>>> +     .set_vq_ready           = vduse_vdpa_set_vq_ready,
>>>>> +     .get_vq_ready           = vduse_vdpa_get_vq_ready,
>>>>> +     .set_vq_state           = vduse_vdpa_set_vq_state,
>>>>> +     .get_vq_state           = vduse_vdpa_get_vq_state,
>>>>> +     .get_vq_align           = vduse_vdpa_get_vq_align,
>>>>> +     .get_features           = vduse_vdpa_get_features,
>>>>> +     .set_features           = vduse_vdpa_set_features,
>>>>> +     .set_config_cb          = vduse_vdpa_set_config_cb,
>>>>> +     .get_vq_num_max         = vduse_vdpa_get_vq_num_max,
>>>>> +     .get_device_id          = vduse_vdpa_get_device_id,
>>>>> +     .get_vendor_id          = vduse_vdpa_get_vendor_id,
>>>>> +     .get_status             = vduse_vdpa_get_status,
>>>>> +     .set_status             = vduse_vdpa_set_status,
>>>>> +     .get_config_size        = vduse_vdpa_get_config_size,
>>>>> +     .get_config             = vduse_vdpa_get_config,
>>>>> +     .set_config             = vduse_vdpa_set_config,
>>>>> +     .get_generation         = vduse_vdpa_get_generation,
>>>>> +     .set_map                = vduse_vdpa_set_map,
>>>>> +     .free                   = vduse_vdpa_free,
>>>>> +};
>>>>> +
>>>>> +static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,
>>>>> +                                  unsigned long offset, size_t size,
>>>>> +                                  enum dma_data_direction dir,
>>>>> +                                  unsigned long attrs)
>>>>> +{
>>>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
>>>>> +     struct vduse_iova_domain *domain = vdev->domain;
>>>>> +
>>>>> +     return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
>>>>> +}
>>>>> +
>>>>> +static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,
>>>>> +                             size_t size, enum dma_data_direction dir,
>>>>> +                             unsigned long attrs)
>>>>> +{
>>>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
>>>>> +     struct vduse_iova_domain *domain = vdev->domain;
>>>>> +
>>>>> +     return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
>>>>> +}
>>>>> +
>>>>> +static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,
>>>>> +                                     dma_addr_t *dma_addr, gfp_t flag,
>>>>> +                                     unsigned long attrs)
>>>>> +{
>>>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
>>>>> +     struct vduse_iova_domain *domain = vdev->domain;
>>>>> +     unsigned long iova;
>>>>> +     void *addr;
>>>>> +
>>>>> +     *dma_addr = DMA_MAPPING_ERROR;
>>>>> +     addr = vduse_domain_alloc_coherent(domain, size,
>>>>> +                             (dma_addr_t *)&iova, flag, attrs);
>>>>> +     if (!addr)
>>>>> +             return NULL;
>>>>> +
>>>>> +     *dma_addr = (dma_addr_t)iova;
>>>>> +
>>>>> +     return addr;
>>>>> +}
>>>>> +
>>>>> +static void vduse_dev_free_coherent(struct device *dev, size_t size,
>>>>> +                                     void *vaddr, dma_addr_t dma_addr,
>>>>> +                                     unsigned long attrs)
>>>>> +{
>>>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
>>>>> +     struct vduse_iova_domain *domain = vdev->domain;
>>>>> +
>>>>> +     vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
>>>>> +}
>>>>> +
>>>>> +static size_t vduse_dev_max_mapping_size(struct device *dev)
>>>>> +{
>>>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);
>>>>> +     struct vduse_iova_domain *domain = vdev->domain;
>>>>> +
>>>>> +     return domain->bounce_size;
>>>>> +}
>>>>> +
>>>>> +static const struct dma_map_ops vduse_dev_dma_ops = {
>>>>> +     .map_page = vduse_dev_map_page,
>>>>> +     .unmap_page = vduse_dev_unmap_page,
>>>>> +     .alloc = vduse_dev_alloc_coherent,
>>>>> +     .free = vduse_dev_free_coherent,
>>>>> +     .max_mapping_size = vduse_dev_max_mapping_size,
>>>>> +};
>>>>> +
>>>>> +static unsigned int perm_to_file_flags(u8 perm)
>>>>> +{
>>>>> +     unsigned int flags = 0;
>>>>> +
>>>>> +     switch (perm) {
>>>>> +     case VDUSE_ACCESS_WO:
>>>>> +             flags |= O_WRONLY;
>>>>> +             break;
>>>>> +     case VDUSE_ACCESS_RO:
>>>>> +             flags |= O_RDONLY;
>>>>> +             break;
>>>>> +     case VDUSE_ACCESS_RW:
>>>>> +             flags |= O_RDWR;
>>>>> +             break;
>>>>> +     default:
>>>>> +             WARN(1, "invalidate vhost IOTLB permission\n");
>>>>> +             break;
>>>>> +     }
>>>>> +
>>>>> +     return flags;
>>>>> +}
>>>>> +
>>>>> +static int vduse_kickfd_setup(struct vduse_dev *dev,
>>>>> +                     struct vduse_vq_eventfd *eventfd)
>>>>> +{
>>>>> +     struct eventfd_ctx *ctx = NULL;
>>>>> +     struct vduse_virtqueue *vq;
>>>>> +     u32 index;
>>>>> +
>>>>> +     if (eventfd->index >= dev->vq_num)
>>>>> +             return -EINVAL;
>>>>> +
>>>>> +     index = array_index_nospec(eventfd->index, dev->vq_num);
>>>>> +     vq = &dev->vqs[index];
>>>>> +     if (eventfd->fd >= 0) {
>>>>> +             ctx = eventfd_ctx_fdget(eventfd->fd);
>>>>> +             if (IS_ERR(ctx))
>>>>> +                     return PTR_ERR(ctx);
>>>>> +     } else if (eventfd->fd != VDUSE_EVENTFD_DEASSIGN)
>>>>> +             return 0;
>>>>> +
>>>>> +     spin_lock(&vq->kick_lock);
>>>>> +     if (vq->kickfd)
>>>>> +             eventfd_ctx_put(vq->kickfd);
>>>>> +     vq->kickfd = ctx;
>>>>> +     if (vq->ready && vq->kicked && vq->kickfd) {
>>>>> +             eventfd_signal(vq->kickfd, 1);
>>>>> +             vq->kicked = false;
>>>>> +     }
>>>>> +     spin_unlock(&vq->kick_lock);
>>>>> +
>>>>> +     return 0;
>>>>> +}
>>>>> +
>>>>> +static void vduse_dev_irq_inject(struct work_struct *work)
>>>>> +{
>>>>> +     struct vduse_dev *dev = container_of(work, struct vduse_dev, inject);
>>>>> +
>>>>> +     spin_lock_irq(&dev->irq_lock);
>>>>> +     if (dev->config_cb.callback)
>>>>> +             dev->config_cb.callback(dev->config_cb.private);
>>>>> +     spin_unlock_irq(&dev->irq_lock);
>>>>> +}
>>>>> +
>>>>> +static void vduse_vq_irq_inject(struct work_struct *work)
>>>>> +{
>>>>> +     struct vduse_virtqueue *vq = container_of(work,
>>>>> +                                     struct vduse_virtqueue, inject);
>>>>> +
>>>>> +     spin_lock_irq(&vq->irq_lock);
>>>>> +     if (vq->ready && vq->cb.callback)
>>>>> +             vq->cb.callback(vq->cb.private);
>>>>> +     spin_unlock_irq(&vq->irq_lock);
>>>>> +}
>>>>> +
>>>>> +static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
>>>>> +                         unsigned long arg)
>>>>> +{
>>>>> +     struct vduse_dev *dev = file->private_data;
>>>>> +     void __user *argp = (void __user *)arg;
>>>>> +     int ret;
>>>>> +
>>>>> +     switch (cmd) {
>>>>> +     case VDUSE_IOTLB_GET_FD: {
>>>>> +             struct vduse_iotlb_entry entry;
>>>>> +             struct vhost_iotlb_map *map;
>>>>> +             struct vdpa_map_file *map_file;
>>>>> +             struct vduse_iova_domain *domain = dev->domain;
>>>>> +             struct file *f = NULL;
>>>>> +
>>>>> +             ret = -EFAULT;
>>>>> +             if (copy_from_user(&entry, argp, sizeof(entry)))
>>>>> +                     break;
>>>>> +
>>>>> +             ret = -EINVAL;
>>>>> +             if (entry.start > entry.last)
>>>>> +                     break;
>>>>> +
>>>>> +             spin_lock(&domain->iotlb_lock);
>>>>> +             map = vhost_iotlb_itree_first(domain->iotlb,
>>>>> +                                           entry.start, entry.last);
>>>>> +             if (map) {
>>>>> +                     map_file = (struct vdpa_map_file *)map->opaque;
>>>>> +                     f = get_file(map_file->file);
>>>>> +                     entry.offset = map_file->offset;
>>>>> +                     entry.start = map->start;
>>>>> +                     entry.last = map->last;
>>>>> +                     entry.perm = map->perm;
>>>>> +             }
>>>>> +             spin_unlock(&domain->iotlb_lock);
>>>>> +             ret = -EINVAL;
>>>>> +             if (!f)
>>>>> +                     break;
>>>>> +
>>>>> +             ret = -EFAULT;
>>>>> +             if (copy_to_user(argp, &entry, sizeof(entry))) {
>>>>> +                     fput(f);
>>>>> +                     break;
>>>>> +             }
>>>>> +             ret = receive_fd(f, perm_to_file_flags(entry.perm));
>>>>> +             fput(f);
>>>>> +             break;
>>>>> +     }
>>>>> +     case VDUSE_DEV_GET_FEATURES:
>>>>> +             ret = put_user(dev->features, (u64 __user *)argp);
>>>>> +             break;
>>>>> +     case VDUSE_DEV_UPDATE_CONFIG: {
>>>>> +             struct vduse_config_update config;
>>>>> +             unsigned long size = offsetof(struct vduse_config_update,
>>>>> +                                           buffer);
>>>>> +
>>>>> +             ret = -EFAULT;
>>>>> +             if (copy_from_user(&config, argp, size))
>>>>> +                     break;
>>>>> +
>>>>> +             ret = -EINVAL;
>>>>> +             if (config.length == 0 ||
>>>>> +                 config.length > dev->config_size - config.offset)
>>>>> +                     break;
>>>>> +
>>>>> +             ret = -EFAULT;
>>>>> +             if (copy_from_user(dev->config + config.offset, argp + size,
>>>>> +                                config.length))
>>>>> +                     break;
>>>>> +
>>>>> +             ret = 0;
>>>>> +             queue_work(vduse_irq_wq, &dev->inject);
>>>> I wonder if it's better to separate config interrupt out of config
>>>> update or we need document this.
>>>>
>>> I have documented it in the docs. Looks like a config update should be
>>> always followed by a config interrupt. I didn't find a case that uses
>>> them separately.
>> The uAPI doesn't prevent us from the following scenario:
>>
>> update_config(mac[0], ..);
>> update_config(max[1], ..);
>>
>> So it looks to me it's better to separate the config interrupt from the
>> config updating.
>>
> Fine.
>
>>>>> +             break;
>>>>> +     }
>>>>> +     case VDUSE_VQ_GET_INFO: {
>>>> Do we need to limit this only when DRIVER_OK is set?
>>>>
>>> Any reason to add this limitation?
>> Otherwise the vq is not fully initialized, e.g the desc_addr might not
>> be correct.
>>
> The vq_info->ready can be used to tell userspace whether the vq is
> initialized or not.


Yes, this will work as well.

Thanks


>
> Thanks,
> Yongji
>

Yongji Xie June 22, 2021, 8:14 a.m. UTC | #6

On Tue, Jun 22, 2021 at 3:50 PM Jason Wang <[e-mail]> wrote:
>
>
> 在 2021/6/22 下午3:22, Yongji Xie 写道:
> >> We need fix a way to propagate the error to the userspace.
> >>
> >> E.g if we want to stop the deivce, we will delay the status reset until
> >> we get respose from the userspace?
> >>
> > I didn't get how to delay the status reset. And should it be a DoS
> > that we want to fix if the userspace doesn't give a response forever?
>
>
> You're right. So let's make set_status() can fail first, then propagate
> its failure via VHOST_VDPA_SET_STATUS.
>

OK. So we only need to propagate the failure in the vhost-vdpa case, right?

Thanks,
Yongji

Jason Wang June 23, 2021, 3:30 a.m. UTC | #7

在 2021/6/22 下午4:14, Yongji Xie 写道:
> On Tue, Jun 22, 2021 at 3:50 PM Jason Wang <[e-mail]> wrote:
>>
>> 在 2021/6/22 下午3:22, Yongji Xie 写道:
>>>> We need fix a way to propagate the error to the userspace.
>>>>
>>>> E.g if we want to stop the deivce, we will delay the status reset until
>>>> we get respose from the userspace?
>>>>
>>> I didn't get how to delay the status reset. And should it be a DoS
>>> that we want to fix if the userspace doesn't give a response forever?
>>
>> You're right. So let's make set_status() can fail first, then propagate
>> its failure via VHOST_VDPA_SET_STATUS.
>>
> OK. So we only need to propagate the failure in the vhost-vdpa case, right?


I think not, we need to deal with the reset for virtio as well:

E.g in register_virtio_devices(), we have:

         /* We always start by resetting the device, in case a previous
          * driver messed it up.  This also tests that code path a 
little. */
       dev->config->reset(dev);

We probably need to make reset can fail and then fail the 
register_virtio_device() as well.

Thanks


>
> Thanks,
> Yongji
>

Yongji Xie June 23, 2021, 5:50 a.m. UTC | #8

On Wed, Jun 23, 2021 at 11:31 AM Jason Wang <[e-mail]> wrote:
>
>
> 在 2021/6/22 下午4:14, Yongji Xie 写道:
> > On Tue, Jun 22, 2021 at 3:50 PM Jason Wang <[e-mail]> wrote:
> >>
> >> 在 2021/6/22 下午3:22, Yongji Xie 写道:
> >>>> We need fix a way to propagate the error to the userspace.
> >>>>
> >>>> E.g if we want to stop the deivce, we will delay the status reset until
> >>>> we get respose from the userspace?
> >>>>
> >>> I didn't get how to delay the status reset. And should it be a DoS
> >>> that we want to fix if the userspace doesn't give a response forever?
> >>
> >> You're right. So let's make set_status() can fail first, then propagate
> >> its failure via VHOST_VDPA_SET_STATUS.
> >>
> > OK. So we only need to propagate the failure in the vhost-vdpa case, right?
>
>
> I think not, we need to deal with the reset for virtio as well:
>
> E.g in register_virtio_devices(), we have:
>
>          /* We always start by resetting the device, in case a previous
>           * driver messed it up.  This also tests that code path a
> little. */
>        dev->config->reset(dev);
>
> We probably need to make reset can fail and then fail the
> register_virtio_device() as well.
>

OK, looks like virtio_add_status() and virtio_device_ready()[1] should
be also modified if we need to propagate the failure in the
virtio-vdpa case. Or do we only need to care about the reset case?

[1] https://lore.kernel.org/lkml/[e-mail]/

Thanks,
Yongji

Jason Wang June 24, 2021, 3:34 a.m. UTC | #9

在 2021/6/23 下午1:50, Yongji Xie 写道:
> On Wed, Jun 23, 2021 at 11:31 AM Jason Wang <[e-mail]> wrote:
>>
>> 在 2021/6/22 下午4:14, Yongji Xie 写道:
>>> On Tue, Jun 22, 2021 at 3:50 PM Jason Wang <[e-mail]> wrote:
>>>> 在 2021/6/22 下午3:22, Yongji Xie 写道:
>>>>>> We need fix a way to propagate the error to the userspace.
>>>>>>
>>>>>> E.g if we want to stop the deivce, we will delay the status reset until
>>>>>> we get respose from the userspace?
>>>>>>
>>>>> I didn't get how to delay the status reset. And should it be a DoS
>>>>> that we want to fix if the userspace doesn't give a response forever?
>>>> You're right. So let's make set_status() can fail first, then propagate
>>>> its failure via VHOST_VDPA_SET_STATUS.
>>>>
>>> OK. So we only need to propagate the failure in the vhost-vdpa case, right?
>>
>> I think not, we need to deal with the reset for virtio as well:
>>
>> E.g in register_virtio_devices(), we have:
>>
>>           /* We always start by resetting the device, in case a previous
>>            * driver messed it up.  This also tests that code path a
>> little. */
>>         dev->config->reset(dev);
>>
>> We probably need to make reset can fail and then fail the
>> register_virtio_device() as well.
>>
> OK, looks like virtio_add_status() and virtio_device_ready()[1] should
> be also modified if we need to propagate the failure in the
> virtio-vdpa case. Or do we only need to care about the reset case?
>
> [1] https://lore.kernel.org/lkml/[e-mail]/


My understanding is DRIVER_OK is not something that needs to be validated:

"

DRIVER_OK (4)
Indicates that the driver is set up and ready to drive the device.

"

Since the spec doesn't require to re-read the and check if DRIVER_OK is 
set in 3.1.1 Driver Requirements: Device Initialization.

It's more about "telling the device that driver is ready."

But we don have some status bit that requires the synchronization with 
the device.

1) FEATURES_OK, spec requires to re-read the status bit to check whether 
or it it was set by the device:

"

Re-read device status to ensure the FEATURES_OK bit is still set: 
otherwise, the device does not support our subset of features and the 
device is unusable.

"

This is useful for some device which can only support a subset of the 
features. E.g a device that can only work for packed virtqueue. This 
means the current design of set_features won't work, we need either:

1a) relay the set_features request to userspace

or

1b) introduce a mandated_device_features during device creation and 
validate the driver features during the set_features(), and don't set 
FEATURES_OK if they don't match.


2) Some transports (PCI) requires to re-read the status to ensure the 
synchronization.

"

After writing 0 to device_status, the driver MUST wait for a read of 
device_status to return 0 before reinitializing the device.

"

So we need to deal with both FEATURES_OK and reset, but probably not 
DRIVER_OK.

Thanks


>
> Thanks,
> Yongji
>

Yongji Xie June 24, 2021, 4:46 a.m. UTC | #10

On Thu, Jun 24, 2021 at 11:35 AM Jason Wang <[e-mail]> wrote:
>
>
> 在 2021/6/23 下午1:50, Yongji Xie 写道:
> > On Wed, Jun 23, 2021 at 11:31 AM Jason Wang <[e-mail]> wrote:
> >>
> >> 在 2021/6/22 下午4:14, Yongji Xie 写道:
> >>> On Tue, Jun 22, 2021 at 3:50 PM Jason Wang <[e-mail]> wrote:
> >>>> 在 2021/6/22 下午3:22, Yongji Xie 写道:
> >>>>>> We need fix a way to propagate the error to the userspace.
> >>>>>>
> >>>>>> E.g if we want to stop the deivce, we will delay the status reset until
> >>>>>> we get respose from the userspace?
> >>>>>>
> >>>>> I didn't get how to delay the status reset. And should it be a DoS
> >>>>> that we want to fix if the userspace doesn't give a response forever?
> >>>> You're right. So let's make set_status() can fail first, then propagate
> >>>> its failure via VHOST_VDPA_SET_STATUS.
> >>>>
> >>> OK. So we only need to propagate the failure in the vhost-vdpa case, right?
> >>
> >> I think not, we need to deal with the reset for virtio as well:
> >>
> >> E.g in register_virtio_devices(), we have:
> >>
> >>           /* We always start by resetting the device, in case a previous
> >>            * driver messed it up.  This also tests that code path a
> >> little. */
> >>         dev->config->reset(dev);
> >>
> >> We probably need to make reset can fail and then fail the
> >> register_virtio_device() as well.
> >>
> > OK, looks like virtio_add_status() and virtio_device_ready()[1] should
> > be also modified if we need to propagate the failure in the
> > virtio-vdpa case. Or do we only need to care about the reset case?
> >
> > [1] https://lore.kernel.org/lkml/[e-mail]/
>
>
> My understanding is DRIVER_OK is not something that needs to be validated:
>
> "
>
> DRIVER_OK (4)
> Indicates that the driver is set up and ready to drive the device.
>
> "
>
> Since the spec doesn't require to re-read the and check if DRIVER_OK is
> set in 3.1.1 Driver Requirements: Device Initialization.
>
> It's more about "telling the device that driver is ready."
>
> But we don have some status bit that requires the synchronization with
> the device.
>
> 1) FEATURES_OK, spec requires to re-read the status bit to check whether
> or it it was set by the device:
>
> "
>
> Re-read device status to ensure the FEATURES_OK bit is still set:
> otherwise, the device does not support our subset of features and the
> device is unusable.
>
> "
>
> This is useful for some device which can only support a subset of the
> features. E.g a device that can only work for packed virtqueue. This
> means the current design of set_features won't work, we need either:
>
> 1a) relay the set_features request to userspace
>
> or
>
> 1b) introduce a mandated_device_features during device creation and
> validate the driver features during the set_features(), and don't set
> FEATURES_OK if they don't match.
>
>
> 2) Some transports (PCI) requires to re-read the status to ensure the
> synchronization.
>
> "
>
> After writing 0 to device_status, the driver MUST wait for a read of
> device_status to return 0 before reinitializing the device.
>
> "
>
> So we need to deal with both FEATURES_OK and reset, but probably not
> DRIVER_OK.
>

OK, I see. Thanks for the explanation. One more question is how about
clearing the corresponding status bit in get_status() rather than
making set_status() fail. Since the spec recommends this way for
validation which is done in virtio_dev_remove() and
virtio_finalize_features().

Thanks,
Yongji

Jason Wang June 24, 2021, 8:13 a.m. UTC | #11

在 2021/6/24 下午12:46, Yongji Xie 写道:
>> So we need to deal with both FEATURES_OK and reset, but probably not
>> DRIVER_OK.
>>
> OK, I see. Thanks for the explanation. One more question is how about
> clearing the corresponding status bit in get_status() rather than
> making set_status() fail. Since the spec recommends this way for
> validation which is done in virtio_dev_remove() and
> virtio_finalize_features().
>
> Thanks,
> Yongji
>

I think you can. Or it would be even better that we just don't set the 
bit during set_status().

I just realize that in vdpa_reset() we had:

static inline void vdpa_reset(struct vdpa_device *vdev)
{
         const struct vdpa_config_ops *ops = vdev->config;

         vdev->features_valid = false;
         ops->set_status(vdev, 0);
}

We probably need to add the synchronization here. E.g re-read with a 
timeout.

Thanks

Yongji Xie June 24, 2021, 9:16 a.m. UTC | #12

On Thu, Jun 24, 2021 at 4:14 PM Jason Wang <[e-mail]> wrote:
>
>
> 在 2021/6/24 下午12:46, Yongji Xie 写道:
> >> So we need to deal with both FEATURES_OK and reset, but probably not
> >> DRIVER_OK.
> >>
> > OK, I see. Thanks for the explanation. One more question is how about
> > clearing the corresponding status bit in get_status() rather than
> > making set_status() fail. Since the spec recommends this way for
> > validation which is done in virtio_dev_remove() and
> > virtio_finalize_features().
> >
> > Thanks,
> > Yongji
> >
>
> I think you can. Or it would be even better that we just don't set the
> bit during set_status().
>

Yes, that's what I mean.

> I just realize that in vdpa_reset() we had:
>
> static inline void vdpa_reset(struct vdpa_device *vdev)
> {
>          const struct vdpa_config_ops *ops = vdev->config;
>
>          vdev->features_valid = false;
>          ops->set_status(vdev, 0);
> }
>
> We probably need to add the synchronization here. E.g re-read with a
> timeout.
>

Looks like the timeout is already in set_status(). Do we really need a
duplicated one here? And how to handle failure? Adding a return value
to virtio_config_ops->reset() and passing the error to the upper
layer?

Thanks,
Yongji

Stefan Hajnoczi June 24, 2021, 2:46 p.m. UTC | #13

On Tue, Jun 15, 2021 at 10:13:30PM +0800, Xie Yongji wrote:
> diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> new file mode 100644
> index 000000000000..f21b2e51b5c8
> --- /dev/null
> +++ b/include/uapi/linux/vduse.h
> @@ -0,0 +1,143 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +#ifndef _UAPI_VDUSE_H_
> +#define _UAPI_VDUSE_H_
> +
> +#include <linux/types.h>
> +
> +#define VDUSE_API_VERSION	0
> +
> +#define VDUSE_NAME_MAX	256
> +
> +/* the control messages definition for read/write */
> +
> +enum vduse_req_type {
> +	/* Get the state for virtqueue from userspace */
> +	VDUSE_GET_VQ_STATE,
> +	/* Notify userspace to start the dataplane, no reply */
> +	VDUSE_START_DATAPLANE,
> +	/* Notify userspace to stop the dataplane, no reply */
> +	VDUSE_STOP_DATAPLANE,
> +	/* Notify userspace to update the memory mapping in device IOTLB */
> +	VDUSE_UPDATE_IOTLB,
> +};
> +
> +struct vduse_vq_state {
> +	__u32 index; /* virtqueue index */
> +	__u32 avail_idx; /* virtqueue state (last_avail_idx) */
> +};
> +
> +struct vduse_iova_range {
> +	__u64 start; /* start of the IOVA range */
> +	__u64 last; /* end of the IOVA range */

Please clarify whether this describes a closed range [start, last] or an
open range [start, last).

> +};
> +
> +struct vduse_dev_request {
> +	__u32 type; /* request type */
> +	__u32 request_id; /* request id */
> +#define VDUSE_REQ_FLAGS_NO_REPLY	(1 << 0) /* No need to reply */
> +	__u32 flags; /* request flags */
> +	__u32 reserved; /* for future use */
> +	union {
> +		struct vduse_vq_state vq_state; /* virtqueue state */
> +		struct vduse_iova_range iova; /* iova range for updating */
> +		__u32 padding[16]; /* padding */
> +	};
> +};
> +
> +struct vduse_dev_response {
> +	__u32 request_id; /* corresponding request id */
> +#define VDUSE_REQ_RESULT_OK	0x00
> +#define VDUSE_REQ_RESULT_FAILED	0x01
> +	__u32 result; /* the result of request */
> +	__u32 reserved[2]; /* for future use */
> +	union {
> +		struct vduse_vq_state vq_state; /* virtqueue state */
> +		__u32 padding[16]; /* padding */
> +	};
> +};
> +
> +/* ioctls */
> +
> +struct vduse_dev_config {
> +	char name[VDUSE_NAME_MAX]; /* vduse device name */
> +	__u32 vendor_id; /* virtio vendor id */
> +	__u32 device_id; /* virtio device id */
> +	__u64 features; /* device features */
> +	__u64 bounce_size; /* bounce buffer size for iommu */
> +	__u16 vq_size_max; /* the max size of virtqueue */

The VIRTIO specification allows per-virtqueue sizes. A device can have
two virtqueues, where the first one allows up to 1024 descriptors and
the second one allows only 128 descriptors, for example.

This constant seems to impose the constraint that all virtqueues have
the same maximum size. Is this really necessary?

> +	__u16 padding; /* padding */
> +	__u32 vq_num; /* the number of virtqueues */
> +	__u32 vq_align; /* the allocation alignment of virtqueue's metadata */

I'm not sure what this is?

> +	__u32 config_size; /* the size of the configuration space */
> +	__u32 reserved[15]; /* for future use */
> +	__u8 config[0]; /* the buffer of the configuration space */
> +};
> +
> +struct vduse_iotlb_entry {
> +	__u64 offset; /* the mmap offset on fd */
> +	__u64 start; /* start of the IOVA range */
> +	__u64 last; /* last of the IOVA range */

Same here, please specify whether this is an open range or a closed
range.

> +#define VDUSE_ACCESS_RO 0x1
> +#define VDUSE_ACCESS_WO 0x2
> +#define VDUSE_ACCESS_RW 0x3
> +	__u8 perm; /* access permission of this range */
> +};
> +
> +struct vduse_config_update {
> +	__u32 offset; /* offset from the beginning of configuration space */
> +	__u32 length; /* the length to write to configuration space */
> +	__u8 buffer[0]; /* buffer used to write from */
> +};
> +
> +struct vduse_vq_info {
> +	__u32 index; /* virtqueue index */
> +	__u32 avail_idx; /* virtqueue state (last_avail_idx) */
> +	__u64 desc_addr; /* address of desc area */
> +	__u64 driver_addr; /* address of driver area */
> +	__u64 device_addr; /* address of device area */
> +	__u32 num; /* the size of virtqueue */
> +	__u8 ready; /* ready status of virtqueue */
> +};
> +
> +struct vduse_vq_eventfd {
> +	__u32 index; /* virtqueue index */
> +#define VDUSE_EVENTFD_DEASSIGN -1
> +	int fd; /* eventfd, -1 means de-assigning the eventfd */
> +};
> +
> +#define VDUSE_BASE	0x81
> +
> +/* Get the version of VDUSE API. This is used for future extension */
> +#define VDUSE_GET_API_VERSION	_IOR(VDUSE_BASE, 0x00, __u64)
> +
> +/* Set the version of VDUSE API. */
> +#define VDUSE_SET_API_VERSION	_IOW(VDUSE_BASE, 0x01, __u64)
> +
> +/* Create a vduse device which is represented by a char device (/dev/vduse/<name>) */
> +#define VDUSE_CREATE_DEV	_IOW(VDUSE_BASE, 0x02, struct vduse_dev_config)
> +
> +/* Destroy a vduse device. Make sure there are no references to the char device */
> +#define VDUSE_DESTROY_DEV	_IOW(VDUSE_BASE, 0x03, char[VDUSE_NAME_MAX])
> +
> +/*
> + * Get a file descriptor for the first overlapped iova region,
> + * -EINVAL means the iova region doesn't exist.
> + */
> +#define VDUSE_IOTLB_GET_FD	_IOWR(VDUSE_BASE, 0x04, struct vduse_iotlb_entry)
> +
> +/* Get the negotiated features */
> +#define VDUSE_DEV_GET_FEATURES	_IOR(VDUSE_BASE, 0x05, __u64)
> +
> +/* Update the configuration space */
> +#define VDUSE_DEV_UPDATE_CONFIG	_IOW(VDUSE_BASE, 0x06, struct vduse_config_update)
> +
> +/* Get the specified virtqueue's information */
> +#define VDUSE_VQ_GET_INFO	_IOWR(VDUSE_BASE, 0x07, struct vduse_vq_info)
> +
> +/* Setup an eventfd to receive kick for virtqueue */
> +#define VDUSE_VQ_SETUP_KICKFD	_IOW(VDUSE_BASE, 0x08, struct vduse_vq_eventfd)
> +
> +/* Inject an interrupt for specific virtqueue */
> +#define VDUSE_VQ_INJECT_IRQ	_IOW(VDUSE_BASE, 0x09, __u32)

There is not enough documentation to use this header file. For example,
which ioctls are used with /dev/vduse and which are used with
/dev/vduse/<name>?

Please document that ioctl API fully. It will not only help userspace
developers but also define what is part of the interface and what is an
implementation detail that can change in the future.

Jason Wang June 25, 2021, 3:08 a.m. UTC | #14

在 2021/6/24 下午5:16, Yongji Xie 写道:
> On Thu, Jun 24, 2021 at 4:14 PM Jason Wang <[e-mail]> wrote:
>>
>> 在 2021/6/24 下午12:46, Yongji Xie 写道:
>>>> So we need to deal with both FEATURES_OK and reset, but probably not
>>>> DRIVER_OK.
>>>>
>>> OK, I see. Thanks for the explanation. One more question is how about
>>> clearing the corresponding status bit in get_status() rather than
>>> making set_status() fail. Since the spec recommends this way for
>>> validation which is done in virtio_dev_remove() and
>>> virtio_finalize_features().
>>>
>>> Thanks,
>>> Yongji
>>>
>> I think you can. Or it would be even better that we just don't set the
>> bit during set_status().
>>
> Yes, that's what I mean.
>
>> I just realize that in vdpa_reset() we had:
>>
>> static inline void vdpa_reset(struct vdpa_device *vdev)
>> {
>>           const struct vdpa_config_ops *ops = vdev->config;
>>
>>           vdev->features_valid = false;
>>           ops->set_status(vdev, 0);
>> }
>>
>> We probably need to add the synchronization here. E.g re-read with a
>> timeout.
>>
> Looks like the timeout is already in set_status().


Do you mean the VDUSE's implementation?


>   Do we really need a
> duplicated one here?


1) this is the timeout at the vDPA layer instead of the VDUSE layer.
2) it really depends on what's the meaning of the timeout for set_status 
of VDUSE.

Do we want:

2a) for set_status(): relay the message to userspace and wait for the 
userspace to quiescence the datapath

or

2b) for set_status(): simply relay the message to userspace, reply is no 
needed. Userspace will use a command to update the status when the 
datapath is stop. The the status could be fetched via get_stats().

2b looks more spec complaint.

> And how to handle failure? Adding a return value
> to virtio_config_ops->reset() and passing the error to the upper
> layer?


Something like this.

Thanks


>
> Thanks,
> Yongji
>

Yongji Xie June 25, 2021, 4:19 a.m. UTC | #15

On Fri, Jun 25, 2021 at 11:09 AM Jason Wang <[e-mail]> wrote:
>
>
> 在 2021/6/24 下午5:16, Yongji Xie 写道:
> > On Thu, Jun 24, 2021 at 4:14 PM Jason Wang <[e-mail]> wrote:
> >>
> >> 在 2021/6/24 下午12:46, Yongji Xie 写道:
> >>>> So we need to deal with both FEATURES_OK and reset, but probably not
> >>>> DRIVER_OK.
> >>>>
> >>> OK, I see. Thanks for the explanation. One more question is how about
> >>> clearing the corresponding status bit in get_status() rather than
> >>> making set_status() fail. Since the spec recommends this way for
> >>> validation which is done in virtio_dev_remove() and
> >>> virtio_finalize_features().
> >>>
> >>> Thanks,
> >>> Yongji
> >>>
> >> I think you can. Or it would be even better that we just don't set the
> >> bit during set_status().
> >>
> > Yes, that's what I mean.
> >
> >> I just realize that in vdpa_reset() we had:
> >>
> >> static inline void vdpa_reset(struct vdpa_device *vdev)
> >> {
> >>           const struct vdpa_config_ops *ops = vdev->config;
> >>
> >>           vdev->features_valid = false;
> >>           ops->set_status(vdev, 0);
> >> }
> >>
> >> We probably need to add the synchronization here. E.g re-read with a
> >> timeout.
> >>
> > Looks like the timeout is already in set_status().
>
>
> Do you mean the VDUSE's implementation?
>

Yes.

>
> >   Do we really need a
> > duplicated one here?
>
>
> 1) this is the timeout at the vDPA layer instead of the VDUSE layer.

OK, I get it.

> 2) it really depends on what's the meaning of the timeout for set_status
> of VDUSE.
>
> Do we want:
>
> 2a) for set_status(): relay the message to userspace and wait for the
> userspace to quiescence the datapath
>
> or
>
> 2b) for set_status(): simply relay the message to userspace, reply is no
> needed. Userspace will use a command to update the status when the
> datapath is stop. The the status could be fetched via get_stats().
>
> 2b looks more spec complaint.
>

Looks good to me. And I think we can use the reply of the message to
update the status instead of introducing a new command.

> > And how to handle failure? Adding a return value
> > to virtio_config_ops->reset() and passing the error to the upper
> > layer?
>
>
> Something like this.
>

OK.

Thanks,
Yongji

Jason Wang June 28, 2021, 4:40 a.m. UTC | #16

在 2021/6/25 下午12:19, Yongji Xie 写道:
>> 2b) for set_status(): simply relay the message to userspace, reply is no
>> needed. Userspace will use a command to update the status when the
>> datapath is stop. The the status could be fetched via get_stats().
>>
>> 2b looks more spec complaint.
>>
> Looks good to me. And I think we can use the reply of the message to
> update the status instead of introducing a new command.
>

Just notice this part in virtio_finalize_features():

         virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
         status = dev->config->get_status(dev);
         if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {

So we no reply doesn't work for FEATURES_OK.

So my understanding is:

1) We must not use noreply for set_status()
2) We can use noreply for get_status(), but it requires a new ioctl to 
update the status.

So it looks to me we need synchronize for both get_status() and 
set_status().

Thanks

Yongji Xie June 29, 2021, 2:26 a.m. UTC | #17

On Mon, Jun 28, 2021 at 12:40 PM Jason Wang <[e-mail]> wrote:
>
>
> 在 2021/6/25 下午12:19, Yongji Xie 写道:
> >> 2b) for set_status(): simply relay the message to userspace, reply is no
> >> needed. Userspace will use a command to update the status when the
> >> datapath is stop. The the status could be fetched via get_stats().
> >>
> >> 2b looks more spec complaint.
> >>
> > Looks good to me. And I think we can use the reply of the message to
> > update the status instead of introducing a new command.
> >
>
> Just notice this part in virtio_finalize_features():
>
>          virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
>          status = dev->config->get_status(dev);
>          if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
>
> So we no reply doesn't work for FEATURES_OK.
>
> So my understanding is:
>
> 1) We must not use noreply for set_status()
> 2) We can use noreply for get_status(), but it requires a new ioctl to
> update the status.
>
> So it looks to me we need synchronize for both get_status() and
> set_status().
>

We should not send messages to userspace in the FEATURES_OK case. So
the synchronization is not necessary.

Thanks,
Yongji

Yongji Xie June 29, 2021, 2:59 a.m. UTC | #18

On Mon, Jun 28, 2021 at 9:02 PM Stefan Hajnoczi <[e-mail]> wrote:
>
> On Tue, Jun 15, 2021 at 10:13:30PM +0800, Xie Yongji wrote:
> > diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> > new file mode 100644
> > index 000000000000..f21b2e51b5c8
> > --- /dev/null
> > +++ b/include/uapi/linux/vduse.h
> > @@ -0,0 +1,143 @@
> > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> > +#ifndef _UAPI_VDUSE_H_
> > +#define _UAPI_VDUSE_H_
> > +
> > +#include <linux/types.h>
> > +
> > +#define VDUSE_API_VERSION    0
> > +
> > +#define VDUSE_NAME_MAX       256
> > +
> > +/* the control messages definition for read/write */
> > +
> > +enum vduse_req_type {
> > +     /* Get the state for virtqueue from userspace */
> > +     VDUSE_GET_VQ_STATE,
> > +     /* Notify userspace to start the dataplane, no reply */
> > +     VDUSE_START_DATAPLANE,
> > +     /* Notify userspace to stop the dataplane, no reply */
> > +     VDUSE_STOP_DATAPLANE,
> > +     /* Notify userspace to update the memory mapping in device IOTLB */
> > +     VDUSE_UPDATE_IOTLB,
> > +};
> > +
> > +struct vduse_vq_state {
> > +     __u32 index; /* virtqueue index */
> > +     __u32 avail_idx; /* virtqueue state (last_avail_idx) */
> > +};
> > +
> > +struct vduse_iova_range {
> > +     __u64 start; /* start of the IOVA range */
> > +     __u64 last; /* end of the IOVA range */
>
> Please clarify whether this describes a closed range [start, last] or an
> open range [start, last).
>

OK.

> > +};
> > +
> > +struct vduse_dev_request {
> > +     __u32 type; /* request type */
> > +     __u32 request_id; /* request id */
> > +#define VDUSE_REQ_FLAGS_NO_REPLY     (1 << 0) /* No need to reply */
> > +     __u32 flags; /* request flags */
> > +     __u32 reserved; /* for future use */
> > +     union {
> > +             struct vduse_vq_state vq_state; /* virtqueue state */
> > +             struct vduse_iova_range iova; /* iova range for updating */
> > +             __u32 padding[16]; /* padding */
> > +     };
> > +};
> > +
> > +struct vduse_dev_response {
> > +     __u32 request_id; /* corresponding request id */
> > +#define VDUSE_REQ_RESULT_OK  0x00
> > +#define VDUSE_REQ_RESULT_FAILED      0x01
> > +     __u32 result; /* the result of request */
> > +     __u32 reserved[2]; /* for future use */
> > +     union {
> > +             struct vduse_vq_state vq_state; /* virtqueue state */
> > +             __u32 padding[16]; /* padding */
> > +     };
> > +};
> > +
> > +/* ioctls */
> > +
> > +struct vduse_dev_config {
> > +     char name[VDUSE_NAME_MAX]; /* vduse device name */
> > +     __u32 vendor_id; /* virtio vendor id */
> > +     __u32 device_id; /* virtio device id */
> > +     __u64 features; /* device features */
> > +     __u64 bounce_size; /* bounce buffer size for iommu */
> > +     __u16 vq_size_max; /* the max size of virtqueue */
>
> The VIRTIO specification allows per-virtqueue sizes. A device can have
> two virtqueues, where the first one allows up to 1024 descriptors and
> the second one allows only 128 descriptors, for example.
>

Good point! But it looks like virtio-vdpa/virtio-pci doesn't support
that now. All virtqueues have the same maximum size.

> This constant seems to impose the constraint that all virtqueues have
> the same maximum size. Is this really necessary?
>

This will be used by vring_create_virtqueue(). We need to specify the
maximum queue size supported by the device.

> > +     __u16 padding; /* padding */
> > +     __u32 vq_num; /* the number of virtqueues */
> > +     __u32 vq_align; /* the allocation alignment of virtqueue's metadata */
>
> I'm not sure what this is?
>

 This will be used by vring_create_virtqueue() too.

> > +     __u32 config_size; /* the size of the configuration space */
> > +     __u32 reserved[15]; /* for future use */
> > +     __u8 config[0]; /* the buffer of the configuration space */
> > +};
> > +
> > +struct vduse_iotlb_entry {
> > +     __u64 offset; /* the mmap offset on fd */
> > +     __u64 start; /* start of the IOVA range */
> > +     __u64 last; /* last of the IOVA range */
>
> Same here, please specify whether this is an open range or a closed
> range.
>

Sure.

> > +#define VDUSE_ACCESS_RO 0x1
> > +#define VDUSE_ACCESS_WO 0x2
> > +#define VDUSE_ACCESS_RW 0x3
> > +     __u8 perm; /* access permission of this range */
> > +};
> > +
> > +struct vduse_config_update {
> > +     __u32 offset; /* offset from the beginning of configuration space */
> > +     __u32 length; /* the length to write to configuration space */
> > +     __u8 buffer[0]; /* buffer used to write from */
> > +};
> > +
> > +struct vduse_vq_info {
> > +     __u32 index; /* virtqueue index */
> > +     __u32 avail_idx; /* virtqueue state (last_avail_idx) */
> > +     __u64 desc_addr; /* address of desc area */
> > +     __u64 driver_addr; /* address of driver area */
> > +     __u64 device_addr; /* address of device area */
> > +     __u32 num; /* the size of virtqueue */
> > +     __u8 ready; /* ready status of virtqueue */
> > +};
> > +
> > +struct vduse_vq_eventfd {
> > +     __u32 index; /* virtqueue index */
> > +#define VDUSE_EVENTFD_DEASSIGN -1
> > +     int fd; /* eventfd, -1 means de-assigning the eventfd */
> > +};
> > +
> > +#define VDUSE_BASE   0x81
> > +
> > +/* Get the version of VDUSE API. This is used for future extension */
> > +#define VDUSE_GET_API_VERSION        _IOR(VDUSE_BASE, 0x00, __u64)
> > +
> > +/* Set the version of VDUSE API. */
> > +#define VDUSE_SET_API_VERSION        _IOW(VDUSE_BASE, 0x01, __u64)
> > +
> > +/* Create a vduse device which is represented by a char device (/dev/vduse/<name>) */
> > +#define VDUSE_CREATE_DEV     _IOW(VDUSE_BASE, 0x02, struct vduse_dev_config)
> > +
> > +/* Destroy a vduse device. Make sure there are no references to the char device */
> > +#define VDUSE_DESTROY_DEV    _IOW(VDUSE_BASE, 0x03, char[VDUSE_NAME_MAX])
> > +
> > +/*
> > + * Get a file descriptor for the first overlapped iova region,
> > + * -EINVAL means the iova region doesn't exist.
> > + */
> > +#define VDUSE_IOTLB_GET_FD   _IOWR(VDUSE_BASE, 0x04, struct vduse_iotlb_entry)
> > +
> > +/* Get the negotiated features */
> > +#define VDUSE_DEV_GET_FEATURES       _IOR(VDUSE_BASE, 0x05, __u64)
> > +
> > +/* Update the configuration space */
> > +#define VDUSE_DEV_UPDATE_CONFIG      _IOW(VDUSE_BASE, 0x06, struct vduse_config_update)
> > +
> > +/* Get the specified virtqueue's information */
> > +#define VDUSE_VQ_GET_INFO    _IOWR(VDUSE_BASE, 0x07, struct vduse_vq_info)
> > +
> > +/* Setup an eventfd to receive kick for virtqueue */
> > +#define VDUSE_VQ_SETUP_KICKFD        _IOW(VDUSE_BASE, 0x08, struct vduse_vq_eventfd)
> > +
> > +/* Inject an interrupt for specific virtqueue */
> > +#define VDUSE_VQ_INJECT_IRQ  _IOW(VDUSE_BASE, 0x09, __u32)
>
> There is not enough documentation to use this header file. For example,
> which ioctls are used with /dev/vduse and which are used with
> /dev/vduse/<name>?
>
> Please document that ioctl API fully. It will not only help userspace
> developers but also define what is part of the interface and what is an
> implementation detail that can change in the future.

OK, I will try to add more details.

Thanks,
Yongji

Jason Wang June 29, 2021, 3:29 a.m. UTC | #19

在 2021/6/29 上午10:26, Yongji Xie 写道:
> On Mon, Jun 28, 2021 at 12:40 PM Jason Wang <[e-mail]> wrote:
>>
>> 在 2021/6/25 下午12:19, Yongji Xie 写道:
>>>> 2b) for set_status(): simply relay the message to userspace, reply is no
>>>> needed. Userspace will use a command to update the status when the
>>>> datapath is stop. The the status could be fetched via get_stats().
>>>>
>>>> 2b looks more spec complaint.
>>>>
>>> Looks good to me. And I think we can use the reply of the message to
>>> update the status instead of introducing a new command.
>>>
>> Just notice this part in virtio_finalize_features():
>>
>>           virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
>>           status = dev->config->get_status(dev);
>>           if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
>>
>> So we no reply doesn't work for FEATURES_OK.
>>
>> So my understanding is:
>>
>> 1) We must not use noreply for set_status()
>> 2) We can use noreply for get_status(), but it requires a new ioctl to
>> update the status.
>>
>> So it looks to me we need synchronize for both get_status() and
>> set_status().
>>
> We should not send messages to userspace in the FEATURES_OK case. So
> the synchronization is not necessary.


As discussed previously, there could be a device that mandates some 
features (VIRTIO_F_RING_PACKED). So it can choose to not accept 
FEATURES_OK is packed virtqueue is not negotiated.

In this case we need to relay the message to userspace.

Thanks


>
> Thanks,
> Yongji
>

Yongji Xie June 29, 2021, 3:56 a.m. UTC | #20

On Tue, Jun 29, 2021 at 11:29 AM Jason Wang <[e-mail]> wrote:
>
>
> 在 2021/6/29 上午10:26, Yongji Xie 写道:
> > On Mon, Jun 28, 2021 at 12:40 PM Jason Wang <[e-mail]> wrote:
> >>
> >> 在 2021/6/25 下午12:19, Yongji Xie 写道:
> >>>> 2b) for set_status(): simply relay the message to userspace, reply is no
> >>>> needed. Userspace will use a command to update the status when the
> >>>> datapath is stop. The the status could be fetched via get_stats().
> >>>>
> >>>> 2b looks more spec complaint.
> >>>>
> >>> Looks good to me. And I think we can use the reply of the message to
> >>> update the status instead of introducing a new command.
> >>>
> >> Just notice this part in virtio_finalize_features():
> >>
> >>           virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
> >>           status = dev->config->get_status(dev);
> >>           if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
> >>
> >> So we no reply doesn't work for FEATURES_OK.
> >>
> >> So my understanding is:
> >>
> >> 1) We must not use noreply for set_status()
> >> 2) We can use noreply for get_status(), but it requires a new ioctl to
> >> update the status.
> >>
> >> So it looks to me we need synchronize for both get_status() and
> >> set_status().
> >>
> > We should not send messages to userspace in the FEATURES_OK case. So
> > the synchronization is not necessary.
>
>
> As discussed previously, there could be a device that mandates some
> features (VIRTIO_F_RING_PACKED). So it can choose to not accept
> FEATURES_OK is packed virtqueue is not negotiated.
>
> In this case we need to relay the message to userspace.
>

OK, I see. If so, I prefer to only use noreply for set_status(). We do
not set the status bit if the message is failed. In this way, we don't
need to change lots of virtio core codes to handle the failure of
set_status()/get_status().

Thanks,
Yongji

Jason Wang June 29, 2021, 4:03 a.m. UTC | #21

在 2021/6/29 上午11:56, Yongji Xie 写道:
> On Tue, Jun 29, 2021 at 11:29 AM Jason Wang <[e-mail]> wrote:
>>
>> 在 2021/6/29 上午10:26, Yongji Xie 写道:
>>> On Mon, Jun 28, 2021 at 12:40 PM Jason Wang <[e-mail]> wrote:
>>>> 在 2021/6/25 下午12:19, Yongji Xie 写道:
>>>>>> 2b) for set_status(): simply relay the message to userspace, reply is no
>>>>>> needed. Userspace will use a command to update the status when the
>>>>>> datapath is stop. The the status could be fetched via get_stats().
>>>>>>
>>>>>> 2b looks more spec complaint.
>>>>>>
>>>>> Looks good to me. And I think we can use the reply of the message to
>>>>> update the status instead of introducing a new command.
>>>>>
>>>> Just notice this part in virtio_finalize_features():
>>>>
>>>>            virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
>>>>            status = dev->config->get_status(dev);
>>>>            if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
>>>>
>>>> So we no reply doesn't work for FEATURES_OK.
>>>>
>>>> So my understanding is:
>>>>
>>>> 1) We must not use noreply for set_status()
>>>> 2) We can use noreply for get_status(), but it requires a new ioctl to
>>>> update the status.
>>>>
>>>> So it looks to me we need synchronize for both get_status() and
>>>> set_status().
>>>>
>>> We should not send messages to userspace in the FEATURES_OK case. So
>>> the synchronization is not necessary.
>>
>> As discussed previously, there could be a device that mandates some
>> features (VIRTIO_F_RING_PACKED). So it can choose to not accept
>> FEATURES_OK is packed virtqueue is not negotiated.
>>
>> In this case we need to relay the message to userspace.
>>
> OK, I see. If so, I prefer to only use noreply for set_status(). We do
> not set the status bit if the message is failed. In this way, we don't
> need to change lots of virtio core codes to handle the failure of
> set_status()/get_status().


It should work.

Thanks


>
> Thanks,
> Yongji
>

Stefan Hajnoczi June 30, 2021, 9:51 a.m. UTC | #22

On Tue, Jun 29, 2021 at 10:59:51AM +0800, Yongji Xie wrote:
> On Mon, Jun 28, 2021 at 9:02 PM Stefan Hajnoczi <[e-mail]> wrote:
> >
> > On Tue, Jun 15, 2021 at 10:13:30PM +0800, Xie Yongji wrote:
> > > +/* ioctls */
> > > +
> > > +struct vduse_dev_config {
> > > +     char name[VDUSE_NAME_MAX]; /* vduse device name */
> > > +     __u32 vendor_id; /* virtio vendor id */
> > > +     __u32 device_id; /* virtio device id */
> > > +     __u64 features; /* device features */
> > > +     __u64 bounce_size; /* bounce buffer size for iommu */
> > > +     __u16 vq_size_max; /* the max size of virtqueue */
> >
> > The VIRTIO specification allows per-virtqueue sizes. A device can have
> > two virtqueues, where the first one allows up to 1024 descriptors and
> > the second one allows only 128 descriptors, for example.
> >
> 
> Good point! But it looks like virtio-vdpa/virtio-pci doesn't support
> that now. All virtqueues have the same maximum size.

I see struct vpda_config_ops only supports a per-device max vq size:
u16 (*get_vq_num_max)(struct vdpa_device *vdev);

virtio-pci supports per-virtqueue sizes because the struct
virtio_pci_common_cfg->queue_size register is per-queue (controlled by
queue_select).

I guess this is a question for Jason: will vdpa will keep this limitation?
If yes, then VDUSE can stick to it too without running into problems in
the future.

> > > +     __u16 padding; /* padding */
> > > +     __u32 vq_num; /* the number of virtqueues */
> > > +     __u32 vq_align; /* the allocation alignment of virtqueue's metadata */
> >
> > I'm not sure what this is?
> >
> 
>  This will be used by vring_create_virtqueue() too.

If there is no official definition for the meaning of this value then
"/* same as vring_create_virtqueue()'s vring_align parameter */" would
be clearer. That way the reader knows what to research in order to
understand how this field works.

I don't remember but maybe it was used to support vrings when the
host/guest have non-4KB page sizes. I wonder if anyone has an official
definition for this value?

Yongji Xie July 1, 2021, 6:50 a.m. UTC | #23

On Wed, Jun 30, 2021 at 5:51 PM Stefan Hajnoczi <[e-mail]> wrote:
>
> On Tue, Jun 29, 2021 at 10:59:51AM +0800, Yongji Xie wrote:
> > On Mon, Jun 28, 2021 at 9:02 PM Stefan Hajnoczi <[e-mail]> wrote:
> > >
> > > On Tue, Jun 15, 2021 at 10:13:30PM +0800, Xie Yongji wrote:
> > > > +/* ioctls */
> > > > +
> > > > +struct vduse_dev_config {
> > > > +     char name[VDUSE_NAME_MAX]; /* vduse device name */
> > > > +     __u32 vendor_id; /* virtio vendor id */
> > > > +     __u32 device_id; /* virtio device id */
> > > > +     __u64 features; /* device features */
> > > > +     __u64 bounce_size; /* bounce buffer size for iommu */
> > > > +     __u16 vq_size_max; /* the max size of virtqueue */
> > >
> > > The VIRTIO specification allows per-virtqueue sizes. A device can have
> > > two virtqueues, where the first one allows up to 1024 descriptors and
> > > the second one allows only 128 descriptors, for example.
> > >
> >
> > Good point! But it looks like virtio-vdpa/virtio-pci doesn't support
> > that now. All virtqueues have the same maximum size.
>
> I see struct vpda_config_ops only supports a per-device max vq size:
> u16 (*get_vq_num_max)(struct vdpa_device *vdev);
>
> virtio-pci supports per-virtqueue sizes because the struct
> virtio_pci_common_cfg->queue_size register is per-queue (controlled by
> queue_select).
>

Oh, yes. I miss queue_select.

> I guess this is a question for Jason: will vdpa will keep this limitation?
> If yes, then VDUSE can stick to it too without running into problems in
> the future.
>
> > > > +     __u16 padding; /* padding */
> > > > +     __u32 vq_num; /* the number of virtqueues */
> > > > +     __u32 vq_align; /* the allocation alignment of virtqueue's metadata */
> > >
> > > I'm not sure what this is?
> > >
> >
> >  This will be used by vring_create_virtqueue() too.
>
> If there is no official definition for the meaning of this value then
> "/* same as vring_create_virtqueue()'s vring_align parameter */" would
> be clearer. That way the reader knows what to research in order to
> understand how this field works.
>

OK.

> I don't remember but maybe it was used to support vrings when the
> host/guest have non-4KB page sizes. I wonder if anyone has an official
> definition for this value?

Not sure. Maybe we might need some alignment which is less than
PAGE_SIZE sometimes.

Thanks,
Yongji

Jason Wang July 1, 2021, 7:55 a.m. UTC | #24

在 2021/7/1 下午2:50, Yongji Xie 写道:
> On Wed, Jun 30, 2021 at 5:51 PM Stefan Hajnoczi <[e-mail]> wrote:
>> On Tue, Jun 29, 2021 at 10:59:51AM +0800, Yongji Xie wrote:
>>> On Mon, Jun 28, 2021 at 9:02 PM Stefan Hajnoczi <[e-mail]> wrote:
>>>> On Tue, Jun 15, 2021 at 10:13:30PM +0800, Xie Yongji wrote:
>>>>> +/* ioctls */
>>>>> +
>>>>> +struct vduse_dev_config {
>>>>> +     char name[VDUSE_NAME_MAX]; /* vduse device name */
>>>>> +     __u32 vendor_id; /* virtio vendor id */
>>>>> +     __u32 device_id; /* virtio device id */
>>>>> +     __u64 features; /* device features */
>>>>> +     __u64 bounce_size; /* bounce buffer size for iommu */
>>>>> +     __u16 vq_size_max; /* the max size of virtqueue */
>>>> The VIRTIO specification allows per-virtqueue sizes. A device can have
>>>> two virtqueues, where the first one allows up to 1024 descriptors and
>>>> the second one allows only 128 descriptors, for example.
>>>>
>>> Good point! But it looks like virtio-vdpa/virtio-pci doesn't support
>>> that now. All virtqueues have the same maximum size.
>> I see struct vpda_config_ops only supports a per-device max vq size:
>> u16 (*get_vq_num_max)(struct vdpa_device *vdev);
>>
>> virtio-pci supports per-virtqueue sizes because the struct
>> virtio_pci_common_cfg->queue_size register is per-queue (controlled by
>> queue_select).
>>
> Oh, yes. I miss queue_select.
>
>> I guess this is a question for Jason: will vdpa will keep this limitation?
>> If yes, then VDUSE can stick to it too without running into problems in
>> the future.


I think it's better to extend the get_vq_num_max() per virtqueue.

Currently, vDPA assumes the parent to have a global max size. This seems 
to work on most of the parents but not vp-vDPA (which could be backed by 
QEMU, in that case cvq's size is smaller).

Fortunately, we haven't enabled had cvq support in the userspace now.

I can post the fixes.


>>
>>>>> +     __u16 padding; /* padding */
>>>>> +     __u32 vq_num; /* the number of virtqueues */
>>>>> +     __u32 vq_align; /* the allocation alignment of virtqueue's metadata */
>>>> I'm not sure what this is?
>>>>
>>>   This will be used by vring_create_virtqueue() too.
>> If there is no official definition for the meaning of this value then
>> "/* same as vring_create_virtqueue()'s vring_align parameter */" would
>> be clearer. That way the reader knows what to research in order to
>> understand how this field works.
>>
> OK.
>
>> I don't remember but maybe it was used to support vrings when the
>> host/guest have non-4KB page sizes. I wonder if anyone has an official
>> definition for this value?
> Not sure. Maybe we might need some alignment which is less than
> PAGE_SIZE sometimes.


So I see CCW always use 4096, but I'm not sure whether or not it's 
smaller than PAGE_SIZE.

Thanks


>
> Thanks,
> Yongji
>

Yongji Xie July 1, 2021, 10:26 a.m. UTC | #25

On Thu, Jul 1, 2021 at 3:55 PM Jason Wang <[e-mail]> wrote:
>
>
> 在 2021/7/1 下午2:50, Yongji Xie 写道:
> > On Wed, Jun 30, 2021 at 5:51 PM Stefan Hajnoczi <[e-mail]> wrote:
> >> On Tue, Jun 29, 2021 at 10:59:51AM +0800, Yongji Xie wrote:
> >>> On Mon, Jun 28, 2021 at 9:02 PM Stefan Hajnoczi <[e-mail]> wrote:
> >>>> On Tue, Jun 15, 2021 at 10:13:30PM +0800, Xie Yongji wrote:
> >>>>> +/* ioctls */
> >>>>> +
> >>>>> +struct vduse_dev_config {
> >>>>> +     char name[VDUSE_NAME_MAX]; /* vduse device name */
> >>>>> +     __u32 vendor_id; /* virtio vendor id */
> >>>>> +     __u32 device_id; /* virtio device id */
> >>>>> +     __u64 features; /* device features */
> >>>>> +     __u64 bounce_size; /* bounce buffer size for iommu */
> >>>>> +     __u16 vq_size_max; /* the max size of virtqueue */
> >>>> The VIRTIO specification allows per-virtqueue sizes. A device can have
> >>>> two virtqueues, where the first one allows up to 1024 descriptors and
> >>>> the second one allows only 128 descriptors, for example.
> >>>>
> >>> Good point! But it looks like virtio-vdpa/virtio-pci doesn't support
> >>> that now. All virtqueues have the same maximum size.
> >> I see struct vpda_config_ops only supports a per-device max vq size:
> >> u16 (*get_vq_num_max)(struct vdpa_device *vdev);
> >>
> >> virtio-pci supports per-virtqueue sizes because the struct
> >> virtio_pci_common_cfg->queue_size register is per-queue (controlled by
> >> queue_select).
> >>
> > Oh, yes. I miss queue_select.
> >
> >> I guess this is a question for Jason: will vdpa will keep this limitation?
> >> If yes, then VDUSE can stick to it too without running into problems in
> >> the future.
>
>
> I think it's better to extend the get_vq_num_max() per virtqueue.
>
> Currently, vDPA assumes the parent to have a global max size. This seems
> to work on most of the parents but not vp-vDPA (which could be backed by
> QEMU, in that case cvq's size is smaller).
>
> Fortunately, we haven't enabled had cvq support in the userspace now.
>
> I can post the fixes.
>

OK. If so, it looks like we need to support the per-vq configuration.
I wonder if it's better to use something like: VDUSE_CREATE_DEVICE ->
VDUSE_SETUP_VQ -> VDUSE_SETUP_VQ -> ... -> VDUSE_ENABLE_DEVICE to do
initialization rather than only use VDUSE_CREATE_DEVICE.

Thanks,
Yongji

Jason Wang July 2, 2021, 3:25 a.m. UTC | #26

在 2021/7/1 下午6:26, Yongji Xie 写道:
> On Thu, Jul 1, 2021 at 3:55 PM Jason Wang <[e-mail]> wrote:
>>
>> 在 2021/7/1 下午2:50, Yongji Xie 写道:
>>> On Wed, Jun 30, 2021 at 5:51 PM Stefan Hajnoczi <[e-mail]> wrote:
>>>> On Tue, Jun 29, 2021 at 10:59:51AM +0800, Yongji Xie wrote:
>>>>> On Mon, Jun 28, 2021 at 9:02 PM Stefan Hajnoczi <[e-mail]> wrote:
>>>>>> On Tue, Jun 15, 2021 at 10:13:30PM +0800, Xie Yongji wrote:
>>>>>>> +/* ioctls */
>>>>>>> +
>>>>>>> +struct vduse_dev_config {
>>>>>>> +     char name[VDUSE_NAME_MAX]; /* vduse device name */
>>>>>>> +     __u32 vendor_id; /* virtio vendor id */
>>>>>>> +     __u32 device_id; /* virtio device id */
>>>>>>> +     __u64 features; /* device features */
>>>>>>> +     __u64 bounce_size; /* bounce buffer size for iommu */
>>>>>>> +     __u16 vq_size_max; /* the max size of virtqueue */
>>>>>> The VIRTIO specification allows per-virtqueue sizes. A device can have
>>>>>> two virtqueues, where the first one allows up to 1024 descriptors and
>>>>>> the second one allows only 128 descriptors, for example.
>>>>>>
>>>>> Good point! But it looks like virtio-vdpa/virtio-pci doesn't support
>>>>> that now. All virtqueues have the same maximum size.
>>>> I see struct vpda_config_ops only supports a per-device max vq size:
>>>> u16 (*get_vq_num_max)(struct vdpa_device *vdev);
>>>>
>>>> virtio-pci supports per-virtqueue sizes because the struct
>>>> virtio_pci_common_cfg->queue_size register is per-queue (controlled by
>>>> queue_select).
>>>>
>>> Oh, yes. I miss queue_select.
>>>
>>>> I guess this is a question for Jason: will vdpa will keep this limitation?
>>>> If yes, then VDUSE can stick to it too without running into problems in
>>>> the future.
>>
>> I think it's better to extend the get_vq_num_max() per virtqueue.
>>
>> Currently, vDPA assumes the parent to have a global max size. This seems
>> to work on most of the parents but not vp-vDPA (which could be backed by
>> QEMU, in that case cvq's size is smaller).
>>
>> Fortunately, we haven't enabled had cvq support in the userspace now.
>>
>> I can post the fixes.
>>
> OK. If so, it looks like we need to support the per-vq configuration.
> I wonder if it's better to use something like: VDUSE_CREATE_DEVICE ->
> VDUSE_SETUP_VQ -> VDUSE_SETUP_VQ -> ... -> VDUSE_ENABLE_DEVICE to do
> initialization rather than only use VDUSE_CREATE_DEVICE.


This should be fine.

Thanks


>
> Thanks,
> Yongji
>

Stefan Hajnoczi July 7, 2021, 8:52 a.m. UTC | #27

On Tue, Jun 15, 2021 at 10:13:30PM +0800, Xie Yongji wrote:
> +static bool vduse_validate_config(struct vduse_dev_config *config)
> +{

The name field needs to be NUL terminated?

> +	case VDUSE_CREATE_DEV: {
> +		struct vduse_dev_config config;
> +		unsigned long size = offsetof(struct vduse_dev_config, config);
> +		void *buf;
> +
> +		ret = -EFAULT;
> +		if (copy_from_user(&config, argp, size))
> +			break;
> +
> +		ret = -EINVAL;
> +		if (vduse_validate_config(&config) == false)
> +			break;
> +
> +		buf = vmemdup_user(argp + size, config.config_size);
> +		if (IS_ERR(buf)) {
> +			ret = PTR_ERR(buf);
> +			break;
> +		}
> +		ret = vduse_create_dev(&config, buf, control->api_version);
> +		break;
> +	}
> +	case VDUSE_DESTROY_DEV: {
> +		char name[VDUSE_NAME_MAX];
> +
> +		ret = -EFAULT;
> +		if (copy_from_user(name, argp, VDUSE_NAME_MAX))
> +			break;

Is this missing a NUL terminator?

Yongji Xie July 7, 2021, 9:19 a.m. UTC | #28

On Wed, Jul 7, 2021 at 4:53 PM Stefan Hajnoczi <[e-mail]> wrote:
>
> On Tue, Jun 15, 2021 at 10:13:30PM +0800, Xie Yongji wrote:
> > +static bool vduse_validate_config(struct vduse_dev_config *config)
> > +{
>
> The name field needs to be NUL terminated?
>

I think so.

> > +     case VDUSE_CREATE_DEV: {
> > +             struct vduse_dev_config config;
> > +             unsigned long size = offsetof(struct vduse_dev_config, config);
> > +             void *buf;
> > +
> > +             ret = -EFAULT;
> > +             if (copy_from_user(&config, argp, size))
> > +                     break;
> > +
> > +             ret = -EINVAL;
> > +             if (vduse_validate_config(&config) == false)
> > +                     break;
> > +
> > +             buf = vmemdup_user(argp + size, config.config_size);
> > +             if (IS_ERR(buf)) {
> > +                     ret = PTR_ERR(buf);
> > +                     break;
> > +             }
> > +             ret = vduse_create_dev(&config, buf, control->api_version);
> > +             break;
> > +     }
> > +     case VDUSE_DESTROY_DEV: {
> > +             char name[VDUSE_NAME_MAX];
> > +
> > +             ret = -EFAULT;
> > +             if (copy_from_user(name, argp, VDUSE_NAME_MAX))
> > +                     break;
>
> Is this missing a NUL terminator?

Oh, yes. Looks like I need to set '\0' to name[VDUSE_VDUSE_NAME_MAX - 1] here.

Thanks,
Yongji

Patch

diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index 9bfc2b510c64..acd95e9dcfe7 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -300,6 +300,7 @@  Code  Seq#    Include File                                           Comments
 'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                        conflict!
 '|'   00-7F  linux/media.h
 0x80  00-1F  linux/fb.h
+0x81  00-1F  linux/vduse.h
 0x89  00-06  arch/x86/include/asm/sockios.h
 0x89  0B-DF  linux/sockios.h
 0x89  E0-EF  linux/sockios.h                                         SIOCPROTOPRIVATE range
diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
index a503c1b2bfd9..6e23bce6433a 100644
--- a/drivers/vdpa/Kconfig
+++ b/drivers/vdpa/Kconfig
@@ -33,6 +33,16 @@  config VDPA_SIM_BLOCK
 	  vDPA block device simulator which terminates IO request in a
 	  memory buffer.
 
+config VDPA_USER
+	tristate "VDUSE (vDPA Device in Userspace) support"
+	depends on EVENTFD && MMU && HAS_DMA
+	select DMA_OPS
+	select VHOST_IOTLB
+	select IOMMU_IOVA
+	help
+	  With VDUSE it is possible to emulate a vDPA Device
+	  in a userspace program.
+
 config IFCVF
 	tristate "Intel IFC VF vDPA driver"
 	depends on PCI_MSI
diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile
index 67fe7f3d6943..f02ebed33f19 100644
--- a/drivers/vdpa/Makefile
+++ b/drivers/vdpa/Makefile
@@ -1,6 +1,7 @@ 
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_VDPA) += vdpa.o
 obj-$(CONFIG_VDPA_SIM) += vdpa_sim/
+obj-$(CONFIG_VDPA_USER) += vdpa_user/
 obj-$(CONFIG_IFCVF)    += ifcvf/
 obj-$(CONFIG_MLX5_VDPA) += mlx5/
 obj-$(CONFIG_VP_VDPA)    += virtio_pci/
diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile
new file mode 100644
index 000000000000..260e0b26af99
--- /dev/null
+++ b/drivers/vdpa/vdpa_user/Makefile
@@ -0,0 +1,5 @@ 
+# SPDX-License-Identifier: GPL-2.0
+
+vduse-y := vduse_dev.o iova_domain.o
+
+obj-$(CONFIG_VDPA_USER) += vduse.o
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
new file mode 100644
index 000000000000..5271cbd15e28
--- /dev/null
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -0,0 +1,1453 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * VDUSE: vDPA Device in Userspace
+ *
+ * Copyright (C) 2020-2021 Bytedance Inc. and/or its affiliates. All rights reserved.
+ *
+ * Author: Xie Yongji <[e-mail]>
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/eventfd.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/dma-map-ops.h>
+#include <linux/poll.h>
+#include <linux/file.h>
+#include <linux/uio.h>
+#include <linux/vdpa.h>
+#include <linux/nospec.h>
+#include <uapi/linux/vduse.h>
+#include <uapi/linux/vdpa.h>
+#include <uapi/linux/virtio_config.h>
+#include <uapi/linux/virtio_ids.h>
+#include <uapi/linux/virtio_blk.h>
+#include <linux/mod_devicetable.h>
+
+#include "iova_domain.h"
+
+#define DRV_AUTHOR   "Yongji Xie <[e-mail]>"
+#define DRV_DESC     "vDPA Device in Userspace"
+#define DRV_LICENSE  "GPL v2"
+
+#define VDUSE_DEV_MAX (1U << MINORBITS)
+#define VDUSE_MAX_BOUNCE_SIZE (64 * 1024 * 1024)
+#define VDUSE_IOVA_SIZE (128 * 1024 * 1024)
+#define VDUSE_REQUEST_TIMEOUT 30
+
+struct vduse_virtqueue {
+	u16 index;
+	u32 num;
+	u32 avail_idx;
+	u64 desc_addr;
+	u64 driver_addr;
+	u64 device_addr;
+	bool ready;
+	bool kicked;
+	spinlock_t kick_lock;
+	spinlock_t irq_lock;
+	struct eventfd_ctx *kickfd;
+	struct vdpa_callback cb;
+	struct work_struct inject;
+};
+
+struct vduse_dev;
+
+struct vduse_vdpa {
+	struct vdpa_device vdpa;
+	struct vduse_dev *dev;
+};
+
+struct vduse_dev {
+	struct vduse_vdpa *vdev;
+	struct device *dev;
+	struct vduse_virtqueue *vqs;
+	struct vduse_iova_domain *domain;
+	char *name;
+	struct mutex lock;
+	spinlock_t msg_lock;
+	u64 msg_unique;
+	wait_queue_head_t waitq;
+	struct list_head send_list;
+	struct list_head recv_list;
+	struct vdpa_callback config_cb;
+	struct work_struct inject;
+	spinlock_t irq_lock;
+	int minor;
+	bool connected;
+	bool started;
+	u64 api_version;
+	u64 user_features;
+	u64 features;
+	u32 device_id;
+	u32 vendor_id;
+	u32 generation;
+	u32 config_size;
+	void *config;
+	u8 status;
+	u16 vq_size_max;
+	u32 vq_num;
+	u32 vq_align;
+};
+
+struct vduse_dev_msg {
+	struct vduse_dev_request req;
+	struct vduse_dev_response resp;
+	struct list_head list;
+	wait_queue_head_t waitq;
+	bool completed;
+};
+
+struct vduse_control {
+	u64 api_version;
+};
+
+static DEFINE_MUTEX(vduse_lock);
+static DEFINE_IDR(vduse_idr);
+
+static dev_t vduse_major;
+static struct class *vduse_class;
+static struct cdev vduse_ctrl_cdev;
+static struct cdev vduse_cdev;
+static struct workqueue_struct *vduse_irq_wq;
+
+static u32 allowed_device_id[] = {
+	VIRTIO_ID_BLOCK,
+};
+
+static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa)
+{
+	struct vduse_vdpa *vdev = container_of(vdpa, struct vduse_vdpa, vdpa);
+
+	return vdev->dev;
+}
+
+static inline struct vduse_dev *dev_to_vduse(struct device *dev)
+{
+	struct vdpa_device *vdpa = dev_to_vdpa(dev);
+
+	return vdpa_to_vduse(vdpa);
+}
+
+static struct vduse_dev_msg *vduse_find_msg(struct list_head *head,
+					    uint32_t request_id)
+{
+	struct vduse_dev_msg *msg;
+
+	list_for_each_entry(msg, head, list) {
+		if (msg->req.request_id == request_id) {
+			list_del(&msg->list);
+			return msg;
+		}
+	}
+
+	return NULL;
+}
+
+static struct vduse_dev_msg *vduse_dequeue_msg(struct list_head *head)
+{
+	struct vduse_dev_msg *msg = NULL;
+
+	if (!list_empty(head)) {
+		msg = list_first_entry(head, struct vduse_dev_msg, list);
+		list_del(&msg->list);
+	}
+
+	return msg;
+}
+
+static void vduse_enqueue_msg(struct list_head *head,
+			      struct vduse_dev_msg *msg)
+{
+	list_add_tail(&msg->list, head);
+}
+
+static int vduse_dev_msg_send(struct vduse_dev *dev,
+			      struct vduse_dev_msg *msg, bool no_reply)
+{
+	init_waitqueue_head(&msg->waitq);
+	spin_lock(&dev->msg_lock);
+	msg->req.request_id = dev->msg_unique++;
+	vduse_enqueue_msg(&dev->send_list, msg);
+	wake_up(&dev->waitq);
+	spin_unlock(&dev->msg_lock);
+	if (no_reply)
+		return 0;
+
+	wait_event_killable_timeout(msg->waitq, msg->completed,
+				    VDUSE_REQUEST_TIMEOUT * HZ);
+	spin_lock(&dev->msg_lock);
+	if (!msg->completed) {
+		list_del(&msg->list);
+		msg->resp.result = VDUSE_REQ_RESULT_FAILED;
+	}
+	spin_unlock(&dev->msg_lock);
+
+	return (msg->resp.result == VDUSE_REQ_RESULT_OK) ? 0 : -EIO;
+}
+
+static void vduse_dev_msg_cleanup(struct vduse_dev *dev)
+{
+	struct vduse_dev_msg *msg;
+
+	spin_lock(&dev->msg_lock);
+	while ((msg = vduse_dequeue_msg(&dev->send_list))) {
+		if (msg->req.flags & VDUSE_REQ_FLAGS_NO_REPLY)
+			kfree(msg);
+		else
+			vduse_enqueue_msg(&dev->recv_list, msg);
+	}
+	while ((msg = vduse_dequeue_msg(&dev->recv_list))) {
+		msg->resp.result = VDUSE_REQ_RESULT_FAILED;
+		msg->completed = 1;
+		wake_up(&msg->waitq);
+	}
+	spin_unlock(&dev->msg_lock);
+}
+
+static void vduse_dev_start_dataplane(struct vduse_dev *dev)
+{
+	struct vduse_dev_msg *msg = kzalloc(sizeof(*msg),
+					    GFP_KERNEL | __GFP_NOFAIL);
+
+	msg->req.type = VDUSE_START_DATAPLANE;
+	msg->req.flags |= VDUSE_REQ_FLAGS_NO_REPLY;
+	vduse_dev_msg_send(dev, msg, true);
+}
+
+static void vduse_dev_stop_dataplane(struct vduse_dev *dev)
+{
+	struct vduse_dev_msg *msg = kzalloc(sizeof(*msg),
+					    GFP_KERNEL | __GFP_NOFAIL);
+
+	msg->req.type = VDUSE_STOP_DATAPLANE;
+	msg->req.flags |= VDUSE_REQ_FLAGS_NO_REPLY;
+	vduse_dev_msg_send(dev, msg, true);
+}
+
+static int vduse_dev_get_vq_state(struct vduse_dev *dev,
+				  struct vduse_virtqueue *vq,
+				  struct vdpa_vq_state *state)
+{
+	struct vduse_dev_msg msg = { 0 };
+	int ret;
+
+	msg.req.type = VDUSE_GET_VQ_STATE;
+	msg.req.vq_state.index = vq->index;
+
+	ret = vduse_dev_msg_send(dev, &msg, false);
+	if (ret)
+		return ret;
+
+	state->avail_index = msg.resp.vq_state.avail_idx;
+	return 0;
+}
+
+static int vduse_dev_update_iotlb(struct vduse_dev *dev,
+				u64 start, u64 last)
+{
+	struct vduse_dev_msg msg = { 0 };
+
+	if (last < start)
+		return -EINVAL;
+
+	msg.req.type = VDUSE_UPDATE_IOTLB;
+	msg.req.iova.start = start;
+	msg.req.iova.last = last;
+
+	return vduse_dev_msg_send(dev, &msg, false);
+}
+
+static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct file *file = iocb->ki_filp;
+	struct vduse_dev *dev = file->private_data;
+	struct vduse_dev_msg *msg;
+	int size = sizeof(struct vduse_dev_request);
+	ssize_t ret;
+
+	if (iov_iter_count(to) < size)
+		return -EINVAL;
+
+	spin_lock(&dev->msg_lock);
+	while (1) {
+		msg = vduse_dequeue_msg(&dev->send_list);
+		if (msg)
+			break;
+
+		ret = -EAGAIN;
+		if (file->f_flags & O_NONBLOCK)
+			goto unlock;
+
+		spin_unlock(&dev->msg_lock);
+		ret = wait_event_interruptible_exclusive(dev->waitq,
+					!list_empty(&dev->send_list));
+		if (ret)
+			return ret;
+
+		spin_lock(&dev->msg_lock);
+	}
+	spin_unlock(&dev->msg_lock);
+	ret = copy_to_iter(&msg->req, size, to);
+	spin_lock(&dev->msg_lock);
+	if (ret != size) {
+		ret = -EFAULT;
+		vduse_enqueue_msg(&dev->send_list, msg);
+		goto unlock;
+	}
+	if (msg->req.flags & VDUSE_REQ_FLAGS_NO_REPLY)
+		kfree(msg);
+	else
+		vduse_enqueue_msg(&dev->recv_list, msg);
+unlock:
+	spin_unlock(&dev->msg_lock);
+
+	return ret;
+}
+
+static ssize_t vduse_dev_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct vduse_dev *dev = file->private_data;
+	struct vduse_dev_response resp;
+	struct vduse_dev_msg *msg;
+	size_t ret;
+
+	ret = copy_from_iter(&resp, sizeof(resp), from);
+	if (ret != sizeof(resp))
+		return -EINVAL;
+
+	spin_lock(&dev->msg_lock);
+	msg = vduse_find_msg(&dev->recv_list, resp.request_id);
+	if (!msg) {
+		ret = -ENOENT;
+		goto unlock;
+	}
+
+	memcpy(&msg->resp, &resp, sizeof(resp));
+	msg->completed = 1;
+	wake_up(&msg->waitq);
+unlock:
+	spin_unlock(&dev->msg_lock);
+
+	return ret;
+}
+
+static __poll_t vduse_dev_poll(struct file *file, poll_table *wait)
+{
+	struct vduse_dev *dev = file->private_data;
+	__poll_t mask = 0;
+
+	poll_wait(file, &dev->waitq, wait);
+
+	if (!list_empty(&dev->send_list))
+		mask |= EPOLLIN | EPOLLRDNORM;
+	if (!list_empty(&dev->recv_list))
+		mask |= EPOLLOUT | EPOLLWRNORM;
+
+	return mask;
+}
+
+static void vduse_dev_reset(struct vduse_dev *dev)
+{
+	int i;
+	struct vduse_iova_domain *domain = dev->domain;
+
+	/* The coherent mappings are handled in vduse_dev_free_coherent() */
+	if (domain->bounce_map)
+		vduse_domain_reset_bounce_map(domain);
+
+	dev->features = 0;
+	dev->generation++;
+	spin_lock(&dev->irq_lock);
+	dev->config_cb.callback = NULL;
+	dev->config_cb.private = NULL;
+	spin_unlock(&dev->irq_lock);
+
+	for (i = 0; i < dev->vq_num; i++) {
+		struct vduse_virtqueue *vq = &dev->vqs[i];
+
+		vq->ready = false;
+		vq->desc_addr = 0;
+		vq->driver_addr = 0;
+		vq->device_addr = 0;
+		vq->avail_idx = 0;
+		vq->num = 0;
+
+		spin_lock(&vq->kick_lock);
+		vq->kicked = false;
+		if (vq->kickfd)
+			eventfd_ctx_put(vq->kickfd);
+		vq->kickfd = NULL;
+		spin_unlock(&vq->kick_lock);
+
+		spin_lock(&vq->irq_lock);
+		vq->cb.callback = NULL;
+		vq->cb.private = NULL;
+		spin_unlock(&vq->irq_lock);
+	}
+}
+
+static int vduse_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 idx,
+				u64 desc_area, u64 driver_area,
+				u64 device_area)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	vq->desc_addr = desc_area;
+	vq->driver_addr = driver_area;
+	vq->device_addr = device_area;
+
+	return 0;
+}
+
+static void vduse_vdpa_kick_vq(struct vdpa_device *vdpa, u16 idx)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	spin_lock(&vq->kick_lock);
+	if (!vq->ready)
+		goto unlock;
+
+	if (vq->kickfd)
+		eventfd_signal(vq->kickfd, 1);
+	else
+		vq->kicked = true;
+unlock:
+	spin_unlock(&vq->kick_lock);
+}
+
+static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,
+			      struct vdpa_callback *cb)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	spin_lock(&vq->irq_lock);
+	vq->cb.callback = cb->callback;
+	vq->cb.private = cb->private;
+	spin_unlock(&vq->irq_lock);
+}
+
+static void vduse_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	vq->num = num;
+}
+
+static void vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa,
+					u16 idx, bool ready)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	vq->ready = ready;
+}
+
+static bool vduse_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 idx)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	return vq->ready;
+}
+
+static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,
+				const struct vdpa_vq_state *state)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	vq->avail_idx = state->avail_index;
+	return 0;
+}
+
+static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
+				struct vdpa_vq_state *state)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	struct vduse_virtqueue *vq = &dev->vqs[idx];
+
+	return vduse_dev_get_vq_state(dev, vq, state);
+}
+
+static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return dev->vq_align;
+}
+
+static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return dev->user_features;
+}
+
+static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	dev->features = features;
+	return 0;
+}
+
+static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,
+				  struct vdpa_callback *cb)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	spin_lock(&dev->irq_lock);
+	dev->config_cb.callback = cb->callback;
+	dev->config_cb.private = cb->private;
+	spin_unlock(&dev->irq_lock);
+}
+
+static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return dev->vq_size_max;
+}
+
+static u32 vduse_vdpa_get_device_id(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return dev->device_id;
+}
+
+static u32 vduse_vdpa_get_vendor_id(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return dev->vendor_id;
+}
+
+static u8 vduse_vdpa_get_status(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return dev->status;
+}
+
+static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	bool started = !!(status & VIRTIO_CONFIG_S_DRIVER_OK);
+
+	dev->status = status;
+
+	if (dev->started == started)
+		return;
+
+	dev->started = started;
+	if (dev->started) {
+		vduse_dev_start_dataplane(dev);
+	} else {
+		vduse_dev_reset(dev);
+		vduse_dev_stop_dataplane(dev);
+	}
+}
+
+static size_t vduse_vdpa_get_config_size(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return dev->config_size;
+}
+
+static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,
+				  void *buf, unsigned int len)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	memcpy(buf, dev->config + offset, len);
+}
+
+static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,
+			const void *buf, unsigned int len)
+{
+	/* Now we only support read-only configuration space */
+}
+
+static u32 vduse_vdpa_get_generation(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	return dev->generation;
+}
+
+static int vduse_vdpa_set_map(struct vdpa_device *vdpa,
+				struct vhost_iotlb *iotlb)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	int ret;
+
+	ret = vduse_domain_set_map(dev->domain, iotlb);
+	if (ret)
+		return ret;
+
+	ret = vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
+	if (ret) {
+		vduse_domain_clear_map(dev->domain, iotlb);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void vduse_vdpa_free(struct vdpa_device *vdpa)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	dev->vdev = NULL;
+}
+
+static const struct vdpa_config_ops vduse_vdpa_config_ops = {
+	.set_vq_address		= vduse_vdpa_set_vq_address,
+	.kick_vq		= vduse_vdpa_kick_vq,
+	.set_vq_cb		= vduse_vdpa_set_vq_cb,
+	.set_vq_num             = vduse_vdpa_set_vq_num,
+	.set_vq_ready		= vduse_vdpa_set_vq_ready,
+	.get_vq_ready		= vduse_vdpa_get_vq_ready,
+	.set_vq_state		= vduse_vdpa_set_vq_state,
+	.get_vq_state		= vduse_vdpa_get_vq_state,
+	.get_vq_align		= vduse_vdpa_get_vq_align,
+	.get_features		= vduse_vdpa_get_features,
+	.set_features		= vduse_vdpa_set_features,
+	.set_config_cb		= vduse_vdpa_set_config_cb,
+	.get_vq_num_max		= vduse_vdpa_get_vq_num_max,
+	.get_device_id		= vduse_vdpa_get_device_id,
+	.get_vendor_id		= vduse_vdpa_get_vendor_id,
+	.get_status		= vduse_vdpa_get_status,
+	.set_status		= vduse_vdpa_set_status,
+	.get_config_size	= vduse_vdpa_get_config_size,
+	.get_config		= vduse_vdpa_get_config,
+	.set_config		= vduse_vdpa_set_config,
+	.get_generation		= vduse_vdpa_get_generation,
+	.set_map		= vduse_vdpa_set_map,
+	.free			= vduse_vdpa_free,
+};
+
+static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,
+				     unsigned long offset, size_t size,
+				     enum dma_data_direction dir,
+				     unsigned long attrs)
+{
+	struct vduse_dev *vdev = dev_to_vduse(dev);
+	struct vduse_iova_domain *domain = vdev->domain;
+
+	return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
+}
+
+static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,
+				size_t size, enum dma_data_direction dir,
+				unsigned long attrs)
+{
+	struct vduse_dev *vdev = dev_to_vduse(dev);
+	struct vduse_iova_domain *domain = vdev->domain;
+
+	return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
+}
+
+static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,
+					dma_addr_t *dma_addr, gfp_t flag,
+					unsigned long attrs)
+{
+	struct vduse_dev *vdev = dev_to_vduse(dev);
+	struct vduse_iova_domain *domain = vdev->domain;
+	unsigned long iova;
+	void *addr;
+
+	*dma_addr = DMA_MAPPING_ERROR;
+	addr = vduse_domain_alloc_coherent(domain, size,
+				(dma_addr_t *)&iova, flag, attrs);
+	if (!addr)
+		return NULL;
+
+	*dma_addr = (dma_addr_t)iova;
+
+	return addr;
+}
+
+static void vduse_dev_free_coherent(struct device *dev, size_t size,
+					void *vaddr, dma_addr_t dma_addr,
+					unsigned long attrs)
+{
+	struct vduse_dev *vdev = dev_to_vduse(dev);
+	struct vduse_iova_domain *domain = vdev->domain;
+
+	vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
+}
+
+static size_t vduse_dev_max_mapping_size(struct device *dev)
+{
+	struct vduse_dev *vdev = dev_to_vduse(dev);
+	struct vduse_iova_domain *domain = vdev->domain;
+
+	return domain->bounce_size;
+}
+
+static const struct dma_map_ops vduse_dev_dma_ops = {
+	.map_page = vduse_dev_map_page,
+	.unmap_page = vduse_dev_unmap_page,
+	.alloc = vduse_dev_alloc_coherent,
+	.free = vduse_dev_free_coherent,
+	.max_mapping_size = vduse_dev_max_mapping_size,
+};
+
+static unsigned int perm_to_file_flags(u8 perm)
+{
+	unsigned int flags = 0;
+
+	switch (perm) {
+	case VDUSE_ACCESS_WO:
+		flags |= O_WRONLY;
+		break;
+	case VDUSE_ACCESS_RO:
+		flags |= O_RDONLY;
+		break;
+	case VDUSE_ACCESS_RW:
+		flags |= O_RDWR;
+		break;
+	default:
+		WARN(1, "invalidate vhost IOTLB permission\n");
+		break;
+	}
+
+	return flags;
+}
+
+static int vduse_kickfd_setup(struct vduse_dev *dev,
+			struct vduse_vq_eventfd *eventfd)
+{
+	struct eventfd_ctx *ctx = NULL;
+	struct vduse_virtqueue *vq;
+	u32 index;
+
+	if (eventfd->index >= dev->vq_num)
+		return -EINVAL;
+
+	index = array_index_nospec(eventfd->index, dev->vq_num);
+	vq = &dev->vqs[index];
+	if (eventfd->fd >= 0) {
+		ctx = eventfd_ctx_fdget(eventfd->fd);
+		if (IS_ERR(ctx))
+			return PTR_ERR(ctx);
+	} else if (eventfd->fd != VDUSE_EVENTFD_DEASSIGN)
+		return 0;
+
+	spin_lock(&vq->kick_lock);
+	if (vq->kickfd)
+		eventfd_ctx_put(vq->kickfd);
+	vq->kickfd = ctx;
+	if (vq->ready && vq->kicked && vq->kickfd) {
+		eventfd_signal(vq->kickfd, 1);
+		vq->kicked = false;
+	}
+	spin_unlock(&vq->kick_lock);
+
+	return 0;
+}
+
+static void vduse_dev_irq_inject(struct work_struct *work)
+{
+	struct vduse_dev *dev = container_of(work, struct vduse_dev, inject);
+
+	spin_lock_irq(&dev->irq_lock);
+	if (dev->config_cb.callback)
+		dev->config_cb.callback(dev->config_cb.private);
+	spin_unlock_irq(&dev->irq_lock);
+}
+
+static void vduse_vq_irq_inject(struct work_struct *work)
+{
+	struct vduse_virtqueue *vq = container_of(work,
+					struct vduse_virtqueue, inject);
+
+	spin_lock_irq(&vq->irq_lock);
+	if (vq->ready && vq->cb.callback)
+		vq->cb.callback(vq->cb.private);
+	spin_unlock_irq(&vq->irq_lock);
+}
+
+static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
+			    unsigned long arg)
+{
+	struct vduse_dev *dev = file->private_data;
+	void __user *argp = (void __user *)arg;
+	int ret;
+
+	switch (cmd) {
+	case VDUSE_IOTLB_GET_FD: {
+		struct vduse_iotlb_entry entry;
+		struct vhost_iotlb_map *map;
+		struct vdpa_map_file *map_file;
+		struct vduse_iova_domain *domain = dev->domain;
+		struct file *f = NULL;
+
+		ret = -EFAULT;
+		if (copy_from_user(&entry, argp, sizeof(entry)))
+			break;
+
+		ret = -EINVAL;
+		if (entry.start > entry.last)
+			break;
+
+		spin_lock(&domain->iotlb_lock);
+		map = vhost_iotlb_itree_first(domain->iotlb,
+					      entry.start, entry.last);
+		if (map) {
+			map_file = (struct vdpa_map_file *)map->opaque;
+			f = get_file(map_file->file);
+			entry.offset = map_file->offset;
+			entry.start = map->start;
+			entry.last = map->last;
+			entry.perm = map->perm;
+		}
+		spin_unlock(&domain->iotlb_lock);
+		ret = -EINVAL;
+		if (!f)
+			break;
+
+		ret = -EFAULT;
+		if (copy_to_user(argp, &entry, sizeof(entry))) {
+			fput(f);
+			break;
+		}
+		ret = receive_fd(f, perm_to_file_flags(entry.perm));
+		fput(f);
+		break;
+	}
+	case VDUSE_DEV_GET_FEATURES:
+		ret = put_user(dev->features, (u64 __user *)argp);
+		break;
+	case VDUSE_DEV_UPDATE_CONFIG: {
+		struct vduse_config_update config;
+		unsigned long size = offsetof(struct vduse_config_update,
+					      buffer);
+
+		ret = -EFAULT;
+		if (copy_from_user(&config, argp, size))
+			break;
+
+		ret = -EINVAL;
+		if (config.length == 0 ||
+		    config.length > dev->config_size - config.offset)
+			break;
+
+		ret = -EFAULT;
+		if (copy_from_user(dev->config + config.offset, argp + size,
+				   config.length))
+			break;
+
+		ret = 0;
+		queue_work(vduse_irq_wq, &dev->inject);
+		break;
+	}
+	case VDUSE_VQ_GET_INFO: {
+		struct vduse_vq_info vq_info;
+		u32 vq_index;
+
+		ret = -EFAULT;
+		if (copy_from_user(&vq_info, argp, sizeof(vq_info)))
+			break;
+
+		ret = -EINVAL;
+		if (vq_info.index >= dev->vq_num)
+			break;
+
+		vq_index = array_index_nospec(vq_info.index, dev->vq_num);
+		vq_info.desc_addr = dev->vqs[vq_index].desc_addr;
+		vq_info.driver_addr = dev->vqs[vq_index].driver_addr;
+		vq_info.device_addr = dev->vqs[vq_index].device_addr;
+		vq_info.num = dev->vqs[vq_index].num;
+		vq_info.avail_idx = dev->vqs[vq_index].avail_idx;
+		vq_info.ready = dev->vqs[vq_index].ready;
+
+		ret = -EFAULT;
+		if (copy_to_user(argp, &vq_info, sizeof(vq_info)))
+			break;
+
+		ret = 0;
+		break;
+	}
+	case VDUSE_VQ_SETUP_KICKFD: {
+		struct vduse_vq_eventfd eventfd;
+
+		ret = -EFAULT;
+		if (copy_from_user(&eventfd, argp, sizeof(eventfd)))
+			break;
+
+		ret = vduse_kickfd_setup(dev, &eventfd);
+		break;
+	}
+	case VDUSE_VQ_INJECT_IRQ: {
+		u32 vq_index;
+
+		ret = -EFAULT;
+		if (get_user(vq_index, (u32 __user *)argp))
+			break;
+
+		ret = -EINVAL;
+		if (vq_index >= dev->vq_num)
+			break;
+
+		ret = 0;
+		vq_index = array_index_nospec(vq_index, dev->vq_num);
+		queue_work(vduse_irq_wq, &dev->vqs[vq_index].inject);
+		break;
+	}
+	default:
+		ret = -ENOIOCTLCMD;
+		break;
+	}
+
+	return ret;
+}
+
+static int vduse_dev_release(struct inode *inode, struct file *file)
+{
+	struct vduse_dev *dev = file->private_data;
+
+	spin_lock(&dev->msg_lock);
+	/* Make sure the inflight messages can processed after reconncection */
+	list_splice_init(&dev->recv_list, &dev->send_list);
+	spin_unlock(&dev->msg_lock);
+	dev->connected = false;
+
+	return 0;
+}
+
+static struct vduse_dev *vduse_dev_get_from_minor(int minor)
+{
+	struct vduse_dev *dev;
+
+	mutex_lock(&vduse_lock);
+	dev = idr_find(&vduse_idr, minor);
+	mutex_unlock(&vduse_lock);
+
+	return dev;
+}
+
+static int vduse_dev_open(struct inode *inode, struct file *file)
+{
+	int ret;
+	struct vduse_dev *dev = vduse_dev_get_from_minor(iminor(inode));
+
+	if (!dev)
+		return -ENODEV;
+
+	ret = -EBUSY;
+	mutex_lock(&dev->lock);
+	if (dev->connected)
+		goto unlock;
+
+	ret = 0;
+	dev->connected = true;
+	file->private_data = dev;
+unlock:
+	mutex_unlock(&dev->lock);
+
+	return ret;
+}
+
+static const struct file_operations vduse_dev_fops = {
+	.owner		= THIS_MODULE,
+	.open		= vduse_dev_open,
+	.release	= vduse_dev_release,
+	.read_iter	= vduse_dev_read_iter,
+	.write_iter	= vduse_dev_write_iter,
+	.poll		= vduse_dev_poll,
+	.unlocked_ioctl	= vduse_dev_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.llseek		= noop_llseek,
+};
+
+static struct vduse_dev *vduse_dev_create(void)
+{
+	struct vduse_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+
+	if (!dev)
+		return NULL;
+
+	mutex_init(&dev->lock);
+	spin_lock_init(&dev->msg_lock);
+	INIT_LIST_HEAD(&dev->send_list);
+	INIT_LIST_HEAD(&dev->recv_list);
+	spin_lock_init(&dev->irq_lock);
+
+	INIT_WORK(&dev->inject, vduse_dev_irq_inject);
+	init_waitqueue_head(&dev->waitq);
+
+	return dev;
+}
+
+static void vduse_dev_destroy(struct vduse_dev *dev)
+{
+	kfree(dev);
+}
+
+static struct vduse_dev *vduse_find_dev(const char *name)
+{
+	struct vduse_dev *dev;
+	int id;
+
+	idr_for_each_entry(&vduse_idr, dev, id)
+		if (!strcmp(dev->name, name))
+			return dev;
+
+	return NULL;
+}
+
+static int vduse_destroy_dev(char *name)
+{
+	struct vduse_dev *dev = vduse_find_dev(name);
+
+	if (!dev)
+		return -EINVAL;
+
+	mutex_lock(&dev->lock);
+	if (dev->vdev || dev->connected) {
+		mutex_unlock(&dev->lock);
+		return -EBUSY;
+	}
+	dev->connected = true;
+	mutex_unlock(&dev->lock);
+
+	vduse_dev_msg_cleanup(dev);
+	device_destroy(vduse_class, MKDEV(MAJOR(vduse_major), dev->minor));
+	idr_remove(&vduse_idr, dev->minor);
+	kvfree(dev->config);
+	kfree(dev->vqs);
+	vduse_domain_destroy(dev->domain);
+	kfree(dev->name);
+	vduse_dev_destroy(dev);
+	module_put(THIS_MODULE);
+
+	return 0;
+}
+
+static bool device_is_allowed(u32 device_id)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(allowed_device_id); i++)
+		if (allowed_device_id[i] == device_id)
+			return true;
+
+	return false;
+}
+
+static bool features_is_valid(u64 features)
+{
+	if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))
+		return false;
+
+	/* Now we only support read-only configuration space */
+	if (features & (1ULL << VIRTIO_BLK_F_CONFIG_WCE))
+		return false;
+
+	return true;
+}
+
+static bool vduse_validate_config(struct vduse_dev_config *config)
+{
+	if (config->bounce_size > VDUSE_MAX_BOUNCE_SIZE)
+		return false;
+
+	if (config->vq_align > PAGE_SIZE)
+		return false;
+
+	if (config->config_size > PAGE_SIZE)
+		return false;
+
+	if (!device_is_allowed(config->device_id))
+		return false;
+
+	if (!features_is_valid(config->features))
+		return false;
+
+	return true;
+}
+
+static int vduse_create_dev(struct vduse_dev_config *config,
+			    void *config_buf, u64 api_version)
+{
+	int i, ret;
+	struct vduse_dev *dev;
+
+	ret = -EEXIST;
+	if (vduse_find_dev(config->name))
+		goto err;
+
+	ret = -ENOMEM;
+	dev = vduse_dev_create();
+	if (!dev)
+		goto err;
+
+	dev->api_version = api_version;
+	dev->user_features = config->features;
+	dev->device_id = config->device_id;
+	dev->vendor_id = config->vendor_id;
+	dev->name = kstrdup(config->name, GFP_KERNEL);
+	if (!dev->name)
+		goto err_str;
+
+	dev->domain = vduse_domain_create(VDUSE_IOVA_SIZE - 1,
+					  config->bounce_size);
+	if (!dev->domain)
+		goto err_domain;
+
+	dev->config = config_buf;
+	dev->config_size = config->config_size;
+	dev->vq_align = config->vq_align;
+	dev->vq_size_max = config->vq_size_max;
+	dev->vq_num = config->vq_num;
+	dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), GFP_KERNEL);
+	if (!dev->vqs)
+		goto err_vqs;
+
+	for (i = 0; i < dev->vq_num; i++) {
+		dev->vqs[i].index = i;
+		INIT_WORK(&dev->vqs[i].inject, vduse_vq_irq_inject);
+		spin_lock_init(&dev->vqs[i].kick_lock);
+		spin_lock_init(&dev->vqs[i].irq_lock);
+	}
+
+	ret = idr_alloc(&vduse_idr, dev, 1, VDUSE_DEV_MAX, GFP_KERNEL);
+	if (ret < 0)
+		goto err_idr;
+
+	dev->minor = ret;
+	dev->dev = device_create(vduse_class, NULL,
+				 MKDEV(MAJOR(vduse_major), dev->minor),
+				 NULL, "%s", config->name);
+	if (IS_ERR(dev->dev)) {
+		ret = PTR_ERR(dev->dev);
+		goto err_dev;
+	}
+	__module_get(THIS_MODULE);
+
+	return 0;
+err_dev:
+	idr_remove(&vduse_idr, dev->minor);
+err_idr:
+	kfree(dev->vqs);
+err_vqs:
+	vduse_domain_destroy(dev->domain);
+err_domain:
+	kfree(dev->name);
+err_str:
+	vduse_dev_destroy(dev);
+err:
+	kvfree(config_buf);
+	return ret;
+}
+
+static long vduse_ioctl(struct file *file, unsigned int cmd,
+			unsigned long arg)
+{
+	int ret;
+	void __user *argp = (void __user *)arg;
+	struct vduse_control *control = file->private_data;
+
+	mutex_lock(&vduse_lock);
+	switch (cmd) {
+	case VDUSE_GET_API_VERSION:
+		ret = put_user(control->api_version, (u64 __user *)argp);
+		break;
+	case VDUSE_SET_API_VERSION: {
+		u64 api_version;
+
+		ret = -EFAULT;
+		if (get_user(api_version, (u64 __user *)argp))
+			break;
+
+		ret = -EINVAL;
+		if (api_version > VDUSE_API_VERSION)
+			break;
+
+		ret = 0;
+		control->api_version = api_version;
+		break;
+	}
+	case VDUSE_CREATE_DEV: {
+		struct vduse_dev_config config;
+		unsigned long size = offsetof(struct vduse_dev_config, config);
+		void *buf;
+
+		ret = -EFAULT;
+		if (copy_from_user(&config, argp, size))
+			break;
+
+		ret = -EINVAL;
+		if (vduse_validate_config(&config) == false)
+			break;
+
+		buf = vmemdup_user(argp + size, config.config_size);
+		if (IS_ERR(buf)) {
+			ret = PTR_ERR(buf);
+			break;
+		}
+		ret = vduse_create_dev(&config, buf, control->api_version);
+		break;
+	}
+	case VDUSE_DESTROY_DEV: {
+		char name[VDUSE_NAME_MAX];
+
+		ret = -EFAULT;
+		if (copy_from_user(name, argp, VDUSE_NAME_MAX))
+			break;
+
+		ret = vduse_destroy_dev(name);
+		break;
+	}
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	mutex_unlock(&vduse_lock);
+
+	return ret;
+}
+
+static int vduse_release(struct inode *inode, struct file *file)
+{
+	struct vduse_control *control = file->private_data;
+
+	kfree(control);
+	return 0;
+}
+
+static int vduse_open(struct inode *inode, struct file *file)
+{
+	struct vduse_control *control;
+
+	control = kmalloc(sizeof(struct vduse_control), GFP_KERNEL);
+	if (!control)
+		return -ENOMEM;
+
+	control->api_version = VDUSE_API_VERSION;
+	file->private_data = control;
+
+	return 0;
+}
+
+static const struct file_operations vduse_ctrl_fops = {
+	.owner		= THIS_MODULE,
+	.open		= vduse_open,
+	.release	= vduse_release,
+	.unlocked_ioctl	= vduse_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.llseek		= noop_llseek,
+};
+
+static char *vduse_devnode(struct device *dev, umode_t *mode)
+{
+	return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));
+}
+
+static void vduse_mgmtdev_release(struct device *dev)
+{
+}
+
+static struct device vduse_mgmtdev = {
+	.init_name = "vduse",
+	.release = vduse_mgmtdev_release,
+};
+
+static struct vdpa_mgmt_dev mgmt_dev;
+
+static int vduse_dev_init_vdpa(struct vduse_dev *dev, const char *name)
+{
+	struct vduse_vdpa *vdev;
+	int ret;
+
+	if (dev->vdev)
+		return -EEXIST;
+
+	vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, dev->dev,
+				 &vduse_vdpa_config_ops, name, true);
+	if (!vdev)
+		return -ENOMEM;
+
+	dev->vdev = vdev;
+	vdev->dev = dev;
+	vdev->vdpa.dev.dma_mask = &vdev->vdpa.dev.coherent_dma_mask;
+	ret = dma_set_mask_and_coherent(&vdev->vdpa.dev, DMA_BIT_MASK(64));
+	if (ret) {
+		put_device(&vdev->vdpa.dev);
+		return ret;
+	}
+	set_dma_ops(&vdev->vdpa.dev, &vduse_dev_dma_ops);
+	vdev->vdpa.dma_dev = &vdev->vdpa.dev;
+	vdev->vdpa.mdev = &mgmt_dev;
+
+	return 0;
+}
+
+static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)
+{
+	struct vduse_dev *dev;
+	int ret;
+
+	mutex_lock(&vduse_lock);
+	dev = vduse_find_dev(name);
+	if (!dev) {
+		mutex_unlock(&vduse_lock);
+		return -EINVAL;
+	}
+	ret = vduse_dev_init_vdpa(dev, name);
+	mutex_unlock(&vduse_lock);
+	if (ret)
+		return ret;
+
+	ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);
+	if (ret) {
+		put_device(&dev->vdev->vdpa.dev);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void vdpa_dev_del(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev)
+{
+	_vdpa_unregister_device(dev);
+}
+
+static const struct vdpa_mgmtdev_ops vdpa_dev_mgmtdev_ops = {
+	.dev_add = vdpa_dev_add,
+	.dev_del = vdpa_dev_del,
+};
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static struct vdpa_mgmt_dev mgmt_dev = {
+	.device = &vduse_mgmtdev,
+	.id_table = id_table,
+	.ops = &vdpa_dev_mgmtdev_ops,
+};
+
+static int vduse_mgmtdev_init(void)
+{
+	int ret;
+
+	ret = device_register(&vduse_mgmtdev);
+	if (ret)
+		return ret;
+
+	ret = vdpa_mgmtdev_register(&mgmt_dev);
+	if (ret)
+		goto err;
+
+	return 0;
+err:
+	device_unregister(&vduse_mgmtdev);
+	return ret;
+}
+
+static void vduse_mgmtdev_exit(void)
+{
+	vdpa_mgmtdev_unregister(&mgmt_dev);
+	device_unregister(&vduse_mgmtdev);
+}
+
+static int vduse_init(void)
+{
+	int ret;
+	struct device *dev;
+
+	vduse_class = class_create(THIS_MODULE, "vduse");
+	if (IS_ERR(vduse_class))
+		return PTR_ERR(vduse_class);
+
+	vduse_class->devnode = vduse_devnode;
+
+	ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse");
+	if (ret)
+		goto err_chardev_region;
+
+	/* /dev/vduse/control */
+	cdev_init(&vduse_ctrl_cdev, &vduse_ctrl_fops);
+	vduse_ctrl_cdev.owner = THIS_MODULE;
+	ret = cdev_add(&vduse_ctrl_cdev, vduse_major, 1);
+	if (ret)
+		goto err_ctrl_cdev;
+
+	dev = device_create(vduse_class, NULL, vduse_major, NULL, "control");
+	if (IS_ERR(dev)) {
+		ret = PTR_ERR(dev);
+		goto err_device;
+	}
+
+	/* /dev/vduse/$DEVICE */
+	cdev_init(&vduse_cdev, &vduse_dev_fops);
+	vduse_cdev.owner = THIS_MODULE;
+	ret = cdev_add(&vduse_cdev, MKDEV(MAJOR(vduse_major), 1),
+		       VDUSE_DEV_MAX - 1);
+	if (ret)
+		goto err_cdev;
+
+	vduse_irq_wq = alloc_workqueue("vduse-irq",
+				WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);
+	if (!vduse_irq_wq)
+		goto err_wq;
+
+	ret = vduse_domain_init();
+	if (ret)
+		goto err_domain;
+
+	ret = vduse_mgmtdev_init();
+	if (ret)
+		goto err_mgmtdev;
+
+	return 0;
+err_mgmtdev:
+	vduse_domain_exit();
+err_domain:
+	destroy_workqueue(vduse_irq_wq);
+err_wq:
+	cdev_del(&vduse_cdev);
+err_cdev:
+	device_destroy(vduse_class, vduse_major);
+err_device:
+	cdev_del(&vduse_ctrl_cdev);
+err_ctrl_cdev:
+	unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
+err_chardev_region:
+	class_destroy(vduse_class);
+	return ret;
+}
+module_init(vduse_init);
+
+static void vduse_exit(void)
+{
+	vduse_mgmtdev_exit();
+	vduse_domain_exit();
+	destroy_workqueue(vduse_irq_wq);
+	cdev_del(&vduse_cdev);
+	device_destroy(vduse_class, vduse_major);
+	cdev_del(&vduse_ctrl_cdev);
+	unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
+	class_destroy(vduse_class);
+}
+module_exit(vduse_exit);
+
+MODULE_LICENSE(DRV_LICENSE);
+MODULE_AUTHOR(DRV_AUTHOR);
+MODULE_DESCRIPTION(DRV_DESC);
diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
new file mode 100644
index 000000000000..f21b2e51b5c8
--- /dev/null
+++ b/include/uapi/linux/vduse.h
@@ -0,0 +1,143 @@ 
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_VDUSE_H_
+#define _UAPI_VDUSE_H_
+
+#include <linux/types.h>
+
+#define VDUSE_API_VERSION	0
+
+#define VDUSE_NAME_MAX	256
+
+/* the control messages definition for read/write */
+
+enum vduse_req_type {
+	/* Get the state for virtqueue from userspace */
+	VDUSE_GET_VQ_STATE,
+	/* Notify userspace to start the dataplane, no reply */
+	VDUSE_START_DATAPLANE,
+	/* Notify userspace to stop the dataplane, no reply */
+	VDUSE_STOP_DATAPLANE,
+	/* Notify userspace to update the memory mapping in device IOTLB */
+	VDUSE_UPDATE_IOTLB,
+};
+
+struct vduse_vq_state {
+	__u32 index; /* virtqueue index */
+	__u32 avail_idx; /* virtqueue state (last_avail_idx) */
+};
+
+struct vduse_iova_range {
+	__u64 start; /* start of the IOVA range */
+	__u64 last; /* end of the IOVA range */
+};
+
+struct vduse_dev_request {
+	__u32 type; /* request type */
+	__u32 request_id; /* request id */
+#define VDUSE_REQ_FLAGS_NO_REPLY	(1 << 0) /* No need to reply */
+	__u32 flags; /* request flags */
+	__u32 reserved; /* for future use */
+	union {
+		struct vduse_vq_state vq_state; /* virtqueue state */
+		struct vduse_iova_range iova; /* iova range for updating */
+		__u32 padding[16]; /* padding */
+	};
+};
+
+struct vduse_dev_response {
+	__u32 request_id; /* corresponding request id */
+#define VDUSE_REQ_RESULT_OK	0x00
+#define VDUSE_REQ_RESULT_FAILED	0x01
+	__u32 result; /* the result of request */
+	__u32 reserved[2]; /* for future use */
+	union {
+		struct vduse_vq_state vq_state; /* virtqueue state */
+		__u32 padding[16]; /* padding */
+	};
+};
+
+/* ioctls */
+
+struct vduse_dev_config {
+	char name[VDUSE_NAME_MAX]; /* vduse device name */
+	__u32 vendor_id; /* virtio vendor id */
+	__u32 device_id; /* virtio device id */
+	__u64 features; /* device features */
+	__u64 bounce_size; /* bounce buffer size for iommu */
+	__u16 vq_size_max; /* the max size of virtqueue */
+	__u16 padding; /* padding */
+	__u32 vq_num; /* the number of virtqueues */
+	__u32 vq_align; /* the allocation alignment of virtqueue's metadata */
+	__u32 config_size; /* the size of the configuration space */
+	__u32 reserved[15]; /* for future use */
+	__u8 config[0]; /* the buffer of the configuration space */
+};
+
+struct vduse_iotlb_entry {
+	__u64 offset; /* the mmap offset on fd */
+	__u64 start; /* start of the IOVA range */
+	__u64 last; /* last of the IOVA range */
+#define VDUSE_ACCESS_RO 0x1
+#define VDUSE_ACCESS_WO 0x2
+#define VDUSE_ACCESS_RW 0x3
+	__u8 perm; /* access permission of this range */
+};
+
+struct vduse_config_update {
+	__u32 offset; /* offset from the beginning of configuration space */
+	__u32 length; /* the length to write to configuration space */
+	__u8 buffer[0]; /* buffer used to write from */
+};
+
+struct vduse_vq_info {
+	__u32 index; /* virtqueue index */
+	__u32 avail_idx; /* virtqueue state (last_avail_idx) */
+	__u64 desc_addr; /* address of desc area */
+	__u64 driver_addr; /* address of driver area */
+	__u64 device_addr; /* address of device area */
+	__u32 num; /* the size of virtqueue */
+	__u8 ready; /* ready status of virtqueue */
+};
+
+struct vduse_vq_eventfd {
+	__u32 index; /* virtqueue index */
+#define VDUSE_EVENTFD_DEASSIGN -1
+	int fd; /* eventfd, -1 means de-assigning the eventfd */
+};
+
+#define VDUSE_BASE	0x81
+
+/* Get the version of VDUSE API. This is used for future extension */
+#define VDUSE_GET_API_VERSION	_IOR(VDUSE_BASE, 0x00, __u64)
+
+/* Set the version of VDUSE API. */
+#define VDUSE_SET_API_VERSION	_IOW(VDUSE_BASE, 0x01, __u64)
+
+/* Create a vduse device which is represented by a char device (/dev/vduse/<name>) */
+#define VDUSE_CREATE_DEV	_IOW(VDUSE_BASE, 0x02, struct vduse_dev_config)
+
+/* Destroy a vduse device. Make sure there are no references to the char device */
+#define VDUSE_DESTROY_DEV	_IOW(VDUSE_BASE, 0x03, char[VDUSE_NAME_MAX])
+
+/*
+ * Get a file descriptor for the first overlapped iova region,
+ * -EINVAL means the iova region doesn't exist.
+ */
+#define VDUSE_IOTLB_GET_FD	_IOWR(VDUSE_BASE, 0x04, struct vduse_iotlb_entry)
+
+/* Get the negotiated features */
+#define VDUSE_DEV_GET_FEATURES	_IOR(VDUSE_BASE, 0x05, __u64)
+
+/* Update the configuration space */
+#define VDUSE_DEV_UPDATE_CONFIG	_IOW(VDUSE_BASE, 0x06, struct vduse_config_update)
+
+/* Get the specified virtqueue's information */
+#define VDUSE_VQ_GET_INFO	_IOWR(VDUSE_BASE, 0x07, struct vduse_vq_info)
+
+/* Setup an eventfd to receive kick for virtqueue */
+#define VDUSE_VQ_SETUP_KICKFD	_IOW(VDUSE_BASE, 0x08, struct vduse_vq_eventfd)
+
+/* Inject an interrupt for specific virtqueue */
+#define VDUSE_VQ_INJECT_IRQ	_IOW(VDUSE_BASE, 0x09, __u32)
+
+#endif /* _UAPI_VDUSE_H_ */