[RFC,3/3] drm/virtio: implement blob userptr resource object

Commit Message

Honglei Huang Dec. 20, 2024, 10:04 a.m. UTC

From: Honglei Huang <[e-mail]>

A virtio-gpu userptr is based on HMM notifier.
Used for let host access guest userspace memory and
notice the change of userspace memory.
This series patches are in very beginning state,
User space are pinned currently to ensure the host
device memory operations are correct.
The free and unmap operations for userspace can be
handled by MMU notifier this is a simple and basice
SVM feature for this series patches.
The physical PFNS update operations is splited into
two OPs in here. The evicted memories won't be used
anymore but remap into host again to achieve same
effect with hmm_rang_fault.

Signed-off-by: Honglei Huang <[e-mail]>
---
 drivers/gpu/drm/virtio/Makefile          |   3 +-
 drivers/gpu/drm/virtio/virtgpu_drv.h     |  72 +++
 drivers/gpu/drm/virtio/virtgpu_ioctl.c   |  25 +-
 drivers/gpu/drm/virtio/virtgpu_kms.c     |   2 +
 drivers/gpu/drm/virtio/virtgpu_object.c  |   5 +
 drivers/gpu/drm/virtio/virtgpu_userptr.c | 738 +++++++++++++++++++++++
 drivers/gpu/drm/virtio/virtgpu_vq.c      |  29 +
 7 files changed, 871 insertions(+), 3 deletions(-)
 create mode 100644 drivers/gpu/drm/virtio/virtgpu_userptr.c

Comments

Simona Vetter Dec. 20, 2024, 3:35 p.m. UTC | #1

On Fri, Dec 20, 2024 at 06:04:09PM +0800, Honglei Huang wrote:
> From: Honglei Huang <[e-mail]>
> 
> A virtio-gpu userptr is based on HMM notifier.
> Used for let host access guest userspace memory and
> notice the change of userspace memory.
> This series patches are in very beginning state,
> User space are pinned currently to ensure the host
> device memory operations are correct.
> The free and unmap operations for userspace can be
> handled by MMU notifier this is a simple and basice
> SVM feature for this series patches.
> The physical PFNS update operations is splited into
> two OPs in here. The evicted memories won't be used
> anymore but remap into host again to achieve same
> effect with hmm_rang_fault.

So in my opinion there are two ways to implement userptr that make sense:

- pinned userptr with pin_user_pages(FOLL_LONGTERM). there is not mmu
  notifier

- unpinnned userptr where you entirely rely on userptr and do not hold any
  page references or page pins at all, for full SVM integration. This
  should use hmm_range_fault ideally, since that's the version that
  doesn't ever grab any page reference pins.

All the in-between variants are imo really bad hacks, whether they hold a
page reference or a temporary page pin (which seems to be what you're
doing here). In much older kernels there was some justification for them,
because strange stuff happened over fork(), but with FOLL_LONGTERM this is
now all sorted out. So there's really only fully pinned, or true svm left
as clean design choices imo.

With that background, why does pin_user_pages(FOLL_LONGTERM) not work for
you?

The other part is that I think we really should extract these into
helpers. Definitely for the pinned variant, that should be really simple.

Cheers, Sima

> 
> Signed-off-by: Honglei Huang <[e-mail]>
> ---
>  drivers/gpu/drm/virtio/Makefile          |   3 +-
>  drivers/gpu/drm/virtio/virtgpu_drv.h     |  72 +++
>  drivers/gpu/drm/virtio/virtgpu_ioctl.c   |  25 +-
>  drivers/gpu/drm/virtio/virtgpu_kms.c     |   2 +
>  drivers/gpu/drm/virtio/virtgpu_object.c  |   5 +
>  drivers/gpu/drm/virtio/virtgpu_userptr.c | 738 +++++++++++++++++++++++
>  drivers/gpu/drm/virtio/virtgpu_vq.c      |  29 +
>  7 files changed, 871 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/gpu/drm/virtio/virtgpu_userptr.c
> 
> diff --git a/drivers/gpu/drm/virtio/Makefile b/drivers/gpu/drm/virtio/Makefile
> index d2e1788a8227..351c45e1e7d1 100644
> --- a/drivers/gpu/drm/virtio/Makefile
> +++ b/drivers/gpu/drm/virtio/Makefile
> @@ -2,8 +2,9 @@
>  #
>  # Makefile for the drm device driver.  This driver provides support for the
>  # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
> +# virtgpu_userptr.o
>  
> -virtio-gpu-y := virtgpu_drv.o virtgpu_kms.o virtgpu_gem.o virtgpu_vram.o \
> +virtio-gpu-y := virtgpu_drv.o virtgpu_kms.o virtgpu_gem.o virtgpu_vram.o virtgpu_userptr.o \
>  	virtgpu_display.o virtgpu_vq.o \
>  	virtgpu_fence.o virtgpu_object.o virtgpu_debugfs.o virtgpu_plane.o \
>  	virtgpu_ioctl.o virtgpu_prime.o virtgpu_trace_points.o virtgpu_submit.o
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
> index e1ee17466f6b..5d15c018201d 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.h
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
> @@ -31,6 +31,8 @@
>  #include <linux/virtio_ids.h>
>  #include <linux/virtio_config.h>
>  #include <linux/virtio_gpu.h>
> +#include <linux/mmu_notifier.h>
> +#include <linux/rbtree_types.h>
>  
>  #include <drm/drm_atomic.h>
>  #include <drm/drm_drv.h>
> @@ -85,6 +87,7 @@ struct virtio_gpu_object_params {
>  	uint32_t blob_mem;
>  	uint32_t blob_flags;
>  	uint64_t blob_id;
> +	uint64_t blob_userptr;
>  };
>  
>  struct virtio_gpu_object {
> @@ -112,12 +115,50 @@ struct virtio_gpu_object_vram {
>  	struct drm_mm_node vram_node;
>  };
>  
> +enum userptr_work_list_ops {
> +	USERPTR_OP_NULL,
> +	USERPTR_OP_UNMAP,
> +	USERPTR_OP_UPDATE,
> +	USERPTR_OP_EVICT,
> +};
> +
> +struct virtio_gpu_object_userptr {
> +	struct virtio_gpu_object base;
> +
> +	struct page **pages;
> +	uint64_t userptr_inital_start;
> +	uint64_t userptr_start;
> +	uint64_t userptr_last;
> +	uint32_t npages;
> +	uint32_t bo_handle;
> +	struct list_head work_list;
> +	struct virtio_gpu_device *vgdev;
> +	struct mmu_interval_notifier notifier;
> +	struct drm_file *file;
> +
> +	/* for list work */
> +	struct mm_struct *mm;
> +	enum userptr_work_list_ops op;
> +	uint64_t notifier_start;
> +	uint64_t notifier_last;
> +
> +	/* userptr interval tree node */
> +	struct interval_tree_node it_node;
> +
> +	/* in release list work queue */
> +	atomic_t in_release;
> +	struct mutex lock;
> +};
> +
>  #define to_virtio_gpu_shmem(virtio_gpu_object) \
>  	container_of((virtio_gpu_object), struct virtio_gpu_object_shmem, base)
>  
>  #define to_virtio_gpu_vram(virtio_gpu_object) \
>  	container_of((virtio_gpu_object), struct virtio_gpu_object_vram, base)
>  
> +#define to_virtio_gpu_userptr(virtio_gpu_object) \
> +	container_of((virtio_gpu_object), struct virtio_gpu_object_userptr, base)
> +
>  struct virtio_gpu_object_array {
>  	struct ww_acquire_ctx ticket;
>  	struct list_head next;
> @@ -279,6 +320,16 @@ struct virtio_gpu_fpriv {
>  	uint64_t base_fence_ctx;
>  	uint64_t ring_idx_mask;
>  	struct mutex context_lock;
> +
> +	/* for userptr mmu notifier invalidate */
> +	struct work_struct userptr_invalidate_work;
> +	struct list_head userptr_invalidate_list;
> +	spinlock_t userptr_invalidate_list_lock;
> +
> +	/* userptr interval tree */
> +	struct rb_root_cached userptrs_tree;
> +	struct mutex userptrs_tree_lock;
> +
>  	char debug_name[DEBUG_NAME_MAX_LEN];
>  	bool explicit_debug_name;
>  	bool fence_passing_enabled;
> @@ -422,6 +473,14 @@ virtio_gpu_cmd_resource_create_blob(struct virtio_gpu_device *vgdev,
>  				    struct virtio_gpu_object_params *params,
>  				    struct virtio_gpu_mem_entry *ents,
>  				    uint32_t nents);
> +
> +void
> +virtio_gpu_cmd_resource_create_userptr(struct virtio_gpu_device *vgdev,
> +				    struct virtio_gpu_object *bo,
> +				    struct virtio_gpu_object_params *params,
> +				    unsigned long *pfns,
> +				    uint32_t npfns);
> +
>  void
>  virtio_gpu_cmd_set_scanout_blob(struct virtio_gpu_device *vgdev,
>  				uint32_t scanout_id,
> @@ -497,4 +556,17 @@ void virtio_gpu_vram_unmap_dma_buf(struct device *dev,
>  int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
>  				struct drm_file *file);
>  
> +/* virtgpu_userptr.c */
> +void virtio_gpu_userptr_set_handle(struct virtio_gpu_object *qobj,
> +				   uint32_t handle);
> +uint32_t virtio_gpu_userptr_get_handle(struct virtio_gpu_object *qobj);
> +void virtio_gpu_userptr_list_work_init(struct virtio_gpu_fpriv *vfpriv);
> +void virtio_gpu_userptr_interval_tree_init(struct virtio_gpu_fpriv *vfpriv);
> +uint64_t virtio_gpu_userptr_get_offset(struct virtio_gpu_object *qobj,
> +				       uint64_t addr);
> +bool virtio_gpu_is_userptr(struct virtio_gpu_object *bo);
> +int virtio_gpu_userptr_create(struct virtio_gpu_device *vgdev,
> +			      struct drm_file *file,
> +			      struct virtio_gpu_object_params *params,
> +			      struct virtio_gpu_object **bo_ptr);
>  #endif
> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index d40c7402720d..519278443c66 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -36,7 +36,8 @@
>  
>  #define VIRTGPU_BLOB_FLAG_USE_MASK (VIRTGPU_BLOB_FLAG_USE_MAPPABLE | \
>  				    VIRTGPU_BLOB_FLAG_USE_SHAREABLE | \
> -				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE)
> +				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE | \
> +				    VIRTGPU_BLOB_FLAG_USE_USERPTR)
>  
>  /* Must be called with &virtio_gpu_fpriv.struct_mutex held. */
>  static void virtio_gpu_create_context_locked(struct virtio_gpu_device *vgdev,
> @@ -489,6 +490,7 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
>  	params->size = rc_blob->size;
>  	params->blob = true;
>  	params->blob_flags = rc_blob->blob_flags;
> +	params->blob_userptr = rc_blob->blob_userptr;
>  	return 0;
>  }
>  
> @@ -528,8 +530,20 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
>  				      rc_blob->cmd_size, 0);
>  	}
>  
> -	if (guest_blob)
> +	if (guest_blob && !params.blob_userptr)
>  		ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
> +	else if (guest_blob && params.blob_userptr) {
> +		ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);
> +		if (unlikely(ret < 0))
> +			return ret;
> +		if (ret > 0) {
> +			/* userptr already exist */
> +			rc_blob->res_handle = bo->hw_res_handle;
> +			rc_blob->bo_handle = virtio_gpu_userptr_get_handle(bo);
> +			rc_blob->offset = virtio_gpu_userptr_get_offset(bo, rc_blob->blob_userptr);
> +			return ret;
> +		}
> +	}
>  	else if (!guest_blob && host3d_blob)
>  		ret = virtio_gpu_vram_create(vgdev, &params, &bo);
>  	else
> @@ -560,6 +574,9 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
>  
>  	rc_blob->res_handle = bo->hw_res_handle;
>  	rc_blob->bo_handle = handle;
> +	/* for mmu notifier auto release */
> +	if (guest_blob && params.blob_userptr)
> +		virtio_gpu_userptr_set_handle(bo, handle);
>  
>  	/*
>  	 * The handle owns the reference now.  But we must drop our
> @@ -691,6 +708,10 @@ static int virtio_gpu_context_init_ioctl(struct drm_device *dev,
>  			goto out_unlock;
>  		}
>  	}
> +	if (vfpriv->context_init & VIRTIO_GPU_CAPSET_HSAKMT) {
> +		virtio_gpu_userptr_list_work_init(vfpriv);
> +		virtio_gpu_userptr_interval_tree_init(vfpriv);
> +	}
>  
>  	virtio_gpu_create_context_locked(vgdev, vfpriv);
>  	virtio_gpu_notify(vgdev);
> diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
> index 9f4617a75edd..3af40ed8936a 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_kms.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
> @@ -346,6 +346,8 @@ void virtio_gpu_driver_postclose(struct drm_device *dev, struct drm_file *file)
>  		return;
>  
>  	if (vfpriv->context_created) {
> +		if (vfpriv->context_init & VIRTIO_GPU_CAPSET_HSAKMT)
> +			flush_work(&vfpriv->userptr_invalidate_work);
>  		virtio_gpu_cmd_context_destroy(vgdev, vfpriv->ctx_id);
>  		virtio_gpu_notify(vgdev);
>  	}
> diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
> index c7e74cf13022..31659b0a028d 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_object.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_object.c
> @@ -80,6 +80,11 @@ void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo)
>  		drm_gem_free_mmap_offset(&vram->base.base.base);
>  		drm_gem_object_release(&vram->base.base.base);
>  		kfree(vram);
> +	} else if (virtio_gpu_is_userptr(bo)) {
> +		struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(bo);
> +
> +		drm_gem_object_release(&userptr->base.base.base);
> +		kfree(userptr);
>  	}
>  }
>  
> diff --git a/drivers/gpu/drm/virtio/virtgpu_userptr.c b/drivers/gpu/drm/virtio/virtgpu_userptr.c
> new file mode 100644
> index 000000000000..646088f7f72b
> --- /dev/null
> +++ b/drivers/gpu/drm/virtio/virtgpu_userptr.c
> @@ -0,0 +1,738 @@
> +// SPDX-License-Identifier: GPL-2.0 OR MIT
> +#include "virtgpu_drv.h"
> +
> +#include <linux/dma-mapping.h>
> +
> +#include <linux/mm.h>
> +#include <linux/pid.h>
> +
> +#include "drm/drm_gem.h"
> +
> +#include <linux/mmu_notifier.h>
> +
> +#define USERPTR_PFNS_NO_CHANGE 0
> +#define USERPTR_PFNS_CHANGED 1
> +#define USERPTR_PFNS_NONE 2
> +
> +#define USERPTR_EXISTS 1
> +
> +static bool
> +virtio_gpu_userptr_invalidate(struct mmu_interval_notifier *mn,
> +			      const struct mmu_notifier_range *range,
> +			      unsigned long cur_seq);
> +
> +static const struct mmu_interval_notifier_ops virtio_gpu_userptr_mn_ops = {
> +	.invalidate = virtio_gpu_userptr_invalidate,
> +};
> +
> +static void virtio_gpu_userptr_unlink(struct virtio_gpu_fpriv *vfpriv,
> +				      struct virtio_gpu_object_userptr *userptr)
> +{
> +	if (userptr->it_node.start != 0 && userptr->it_node.last != 0)
> +		interval_tree_remove(&userptr->it_node, &vfpriv->userptrs_tree);
> +}
> +
> +static void virtio_gpu_userptr_free(struct drm_gem_object *obj)
> +{
> +	struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
> +	struct virtio_gpu_device *vgdev = obj->dev->dev_private;
> +	struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(bo);
> +
> +	if (bo->created) {
> +		unpin_user_pages_dirty_lock(userptr->pages, userptr->npages,
> +					    false);
> +		vfree(userptr->pages);
> +		userptr->pages = NULL;
> +
> +		virtio_gpu_cmd_unref_resource(vgdev, bo);
> +		virtio_gpu_notify(vgdev);
> +
> +		return;
> +	}
> +}
> +
> +static void virtio_gpu_userptr_object_close(struct drm_gem_object *obj,
> +					    struct drm_file *file)
> +{
> +	virtio_gpu_gem_object_close(obj, file);
> +}
> +
> +static const struct drm_gem_object_funcs virtio_gpu_userptr_funcs = {
> +	.open = virtio_gpu_gem_object_open,
> +	.close = virtio_gpu_userptr_object_close,
> +	.free = virtio_gpu_userptr_free,
> +};
> +
> +bool virtio_gpu_is_userptr(struct virtio_gpu_object *bo)
> +{
> +	return bo->base.base.funcs == &virtio_gpu_userptr_funcs;
> +}
> +
> +static int
> +virtio_gpu_userptr_add_notifier(struct virtio_gpu_object_userptr *userptr,
> +				unsigned long start, unsigned long length)
> +{
> +	int ret = mmu_interval_notifier_insert_locked(
> +		&userptr->notifier, current->mm, start, length,
> +		&virtio_gpu_userptr_mn_ops);
> +
> +	if (ret)
> +		pr_err("mmu_interval_notifier_insert_locked failed ret: %d\n",
> +		       ret);
> +	return ret;
> +}
> +
> +uint32_t virtio_gpu_userptr_get_handle(struct virtio_gpu_object *qobj)
> +{
> +	struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(qobj);
> +
> +	return userptr->bo_handle;
> +}
> +
> +uint64_t virtio_gpu_userptr_get_offset(struct virtio_gpu_object *qobj,
> +				       uint64_t addr)
> +{
> +	struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(qobj);
> +	uint64_t userptr_align_down = ALIGN_DOWN(addr, PAGE_SIZE);
> +	uint64_t offset = userptr_align_down - userptr->userptr_inital_start;
> +	return offset;
> +}
> +
> +void virtio_gpu_userptr_interval_tree_init(struct virtio_gpu_fpriv *vfpriv)
> +{
> +	vfpriv->userptrs_tree = RB_ROOT_CACHED;
> +	mutex_init(&vfpriv->userptrs_tree_lock);
> +}
> +
> +static struct virtio_gpu_object_userptr *
> +virtio_gpu_userptr_from_addr_range(struct virtio_gpu_fpriv *vfpriv,
> +				   u_int64_t start, u_int64_t last)
> +{
> +	struct interval_tree_node *node;
> +	struct virtio_gpu_object_userptr *userptr = NULL;
> +	struct virtio_gpu_object_userptr *ret = NULL;
> +	uint64_t userptr_size;
> +
> +	node = interval_tree_iter_first(&vfpriv->userptrs_tree, start, last);
> +
> +	while (node) {
> +		struct interval_tree_node *next;
> +
> +		userptr = container_of(node, struct virtio_gpu_object_userptr,
> +				       it_node);
> +
> +		if (start >= userptr->userptr_start &&
> +		    last <= userptr->userptr_last &&
> +		    !atomic_read(&userptr->in_release) && !userptr->op) {
> +			ret = userptr;
> +			userptr_size = userptr->userptr_last -
> +				       userptr->userptr_start + 1UL;
> +			return ret;
> +		}
> +
> +		next = interval_tree_iter_next(node, start, last);
> +		node = next;
> +	}
> +
> +	return ret;
> +}
> +
> +static void
> +virtio_gpu_userptr_add_interval_tree(struct virtio_gpu_fpriv *vfpriv,
> +				     struct virtio_gpu_object_userptr *userptr)
> +{
> +	userptr->it_node.start = userptr->userptr_start;
> +	userptr->it_node.last = userptr->userptr_last;
> +	interval_tree_insert(&userptr->it_node, &vfpriv->userptrs_tree);
> +}
> +
> +static void virtio_gpu_userptr_unmap(struct virtio_gpu_object_userptr *userptr)
> +{
> +	pr_debug(
> +		"list work remove userptr: [%llx-%llx], resid: %d bo_handle: %d size: %x\n",
> +		userptr->userptr_start, userptr->userptr_last,
> +		userptr->base.hw_res_handle, userptr->bo_handle,
> +		userptr->npages);
> +
> +	virtio_gpu_userptr_unlink(userptr->file->driver_priv, userptr);
> +	mmu_interval_notifier_remove(&userptr->notifier);
> +
> +	drm_gem_handle_delete(userptr->file, userptr->bo_handle);
> +}
> +
> +static void virtio_gpu_userptr_update_notifier_and_interval_tree(
> +	struct virtio_gpu_object_userptr *userptr)
> +{
> +	unsigned long start = userptr->notifier.interval_tree.start;
> +	unsigned long last = userptr->notifier.interval_tree.last;
> +
> +	if (userptr->userptr_start == start && userptr->userptr_last == last)
> +		return;
> +
> +	if (start != 0 && last != 0) {
> +		virtio_gpu_userptr_unlink(userptr->file->driver_priv, userptr);
> +		mmu_interval_notifier_remove(&userptr->notifier);
> +	}
> +
> +	pr_debug(
> +		"update userptr: [%lx-%lx]-%lx -> [%llx-%llx]-%llx resid: %d\n",
> +		start, last, last - start + 1UL, userptr->userptr_start,
> +		userptr->userptr_last,
> +		userptr->userptr_last - userptr->userptr_start + 1UL,
> +		userptr->base.hw_res_handle);
> +
> +	virtio_gpu_userptr_add_interval_tree(userptr->file->driver_priv,
> +					     userptr);
> +	mmu_interval_notifier_insert_locked(
> +		&userptr->notifier, userptr->mm, userptr->userptr_start,
> +		userptr->userptr_last - userptr->userptr_start + 1UL,
> +		&virtio_gpu_userptr_mn_ops);
> +
> +	userptr->op = 0;
> +}
> +
> +static int virtio_gpu_userptr_split(struct virtio_gpu_object_userptr *userptr,
> +				    unsigned long valid_start,
> +				    unsigned long valid_last,
> +				    struct virtio_gpu_object_userptr **new)
> +{
> +	uint64_t old_start = userptr->userptr_start;
> +	uint64_t old_last = userptr->userptr_last;
> +
> +	if (old_start != valid_start && old_last != valid_last)
> +		return -EINVAL;
> +	if (valid_start < old_start || valid_last > old_last)
> +		return -EINVAL;
> +
> +	/* split new userptr is not needed currently, but keep the API parameters here
> +	 * for future expansion.
> +	 */
> +	*new = NULL;
> +
> +	/* update range */
> +	userptr->userptr_start = valid_start;
> +	userptr->userptr_last = valid_last;
> +
> +	return 0;
> +}
> +
> +static void
> +virtio_gpu_userptr_update_split(struct virtio_gpu_object_userptr *userptr,
> +				unsigned long mn_start, unsigned long mn_last)
> +{
> +	struct virtio_gpu_object_userptr *head;
> +	struct virtio_gpu_object_userptr *tail;
> +
> +	if (userptr->op == USERPTR_OP_UNMAP)
> +		return;
> +
> +	if (mn_start > userptr->userptr_last ||
> +	    mn_last < userptr->userptr_start)
> +		return;
> +
> +	head = tail = userptr;
> +	if (mn_start > userptr->userptr_start)
> +		virtio_gpu_userptr_split(userptr, userptr->userptr_start,
> +					 mn_start - 1UL, &tail);
> +	else if (mn_last < userptr->userptr_last)
> +		virtio_gpu_userptr_split(userptr, mn_last + 1UL,
> +					 userptr->userptr_last, &head);
> +
> +	/* split tail maybe not needed in virtgpu */
> +	/* if (mn_last < userptr->userptr_last) */
> +	/* add child userptr maybe not needed in virtgpu */
> +}
> +
> +static void
> +virtio_gpu_userptr_add_list_work(struct virtio_gpu_object_userptr *userptr,
> +				 int op)
> +{
> +	struct virtio_gpu_fpriv *vfpriv = userptr->file->driver_priv;
> +
> +	spin_lock(&vfpriv->userptr_invalidate_list_lock);
> +
> +	if (!list_empty(&userptr->work_list)) {
> +		pr_debug(
> +			"update exist userptr userptr: [%llx-%llx] work op to %d\n",
> +			userptr->userptr_start, userptr->userptr_last, op);
> +		if (op != USERPTR_OP_NULL && userptr->op != USERPTR_OP_UNMAP)
> +			userptr->op = op;
> +	} else {
> +		userptr->op = op;
> +		list_add_tail(&userptr->work_list,
> +			      &vfpriv->userptr_invalidate_list);
> +	}
> +
> +	spin_unlock(&vfpriv->userptr_invalidate_list_lock);
> +}
> +
> +static int
> +virtio_gpu_userptr_check_pfns(struct virtio_gpu_object_userptr *userptr,
> +			      struct vm_area_struct *vma, uint64_t start,
> +			      uint64_t end)
> +{
> +	uint64_t addr;
> +	int ret;
> +	unsigned long pfn;
> +	spinlock_t *ptl;
> +	pte_t *ptep;
> +
> +	for (addr = start; addr < end; addr += PAGE_SIZE) {
> +		ret = follow_pte(vma->vm_mm, addr, &ptep, &ptl);
> +		if (ret) {
> +			pr_debug("follow_pfn in userptr failed, addr: %llx\n",
> +				 addr);
> +			return USERPTR_PFNS_NONE;
> +		}
> +		pfn = pte_pfn(ptep_get(ptep));
> +		pte_unmap_unlock(ptep, ptl);
> +		if (page_to_pfn(
> +			    userptr->pages[(addr - userptr->userptr_start) >>
> +					   PAGE_SHIFT]) != pfn) {
> +			pr_debug("userptr pages not match, addr: %llx\n", addr);
> +			return USERPTR_PFNS_CHANGED;
> +		}
> +	}
> +
> +	return USERPTR_PFNS_NO_CHANGE;
> +}
> +
> +static int
> +virtio_gpu_userptr_check_range(struct virtio_gpu_object_userptr *userptr,
> +			       uint64_t notifier_start, uint64_t notifier_last)
> +{
> +	uint64_t start, end, addr;
> +	int r = 0;
> +
> +	start = notifier_start;
> +	end = notifier_last + (1UL << PAGE_SHIFT);
> +
> +	for (addr = start; !r && addr < end;) {
> +		struct vm_area_struct *vma;
> +		uint64_t next = 0;
> +		uint32_t npages;
> +
> +		vma = vma_lookup(userptr->mm, addr);
> +
> +		if (vma) {
> +			next = min(vma->vm_end, end);
> +			npages = (next - addr) >> PAGE_SHIFT;
> +			r = virtio_gpu_userptr_check_pfns(userptr, vma, start,
> +							  next);
> +			if (r)
> +				break;
> +		} else {
> +			pr_debug("vma not found for addr: %llx\n", addr);
> +			r = -EFAULT;
> +			break;
> +		}
> +
> +		addr = next;
> +	}
> +
> +	return r;
> +}
> +
> +static void
> +virtio_gpu_update_or_remove_userptr(struct virtio_gpu_object_userptr *userptr,
> +				    unsigned long start, unsigned long last)
> +{
> +	if ((userptr->userptr_start) >= start &&
> +	    (userptr->userptr_last) <= last) {
> +		if (atomic_xchg(&userptr->in_release, 1) == 0) {
> +			virtio_gpu_userptr_add_list_work(userptr,
> +							 USERPTR_OP_UNMAP);
> +		}
> +	} else {
> +		pr_debug(
> +			"mmu notifier: [%lx-%lx]-%lx userptr: [%llx-%llx]-%llx not match need update.\n",
> +			start, last, last - start + 1UL, userptr->userptr_start,
> +			userptr->userptr_last,
> +			userptr->userptr_last - userptr->userptr_start + 1UL);
> +		virtio_gpu_userptr_update_split(userptr, start, last);
> +		virtio_gpu_userptr_add_list_work(userptr, USERPTR_OP_UPDATE);
> +	}
> +}
> +
> +static void virtio_gpu_userptr_evict(struct virtio_gpu_object_userptr *userptr)
> +{
> +	if (!userptr->notifier_start || !userptr->notifier_last) {
> +		pr_err("userptr: [%llx-%llx] not have notifier range\n",
> +		       userptr->userptr_start, userptr->userptr_last);
> +		return;
> +	}
> +
> +	if (userptr->notifier_start < userptr->userptr_start ||
> +	    userptr->notifier_last > userptr->userptr_last) {
> +		pr_err("invalid evict param, userptr: [%llx-%llx] notifier: [%llx-%llx] out of range\n",
> +		       userptr->userptr_start, userptr->userptr_last,
> +		       userptr->notifier_start, userptr->notifier_last);
> +		return;
> +	}
> +
> +	if (virtio_gpu_userptr_check_range(userptr, userptr->notifier_start,
> +					   userptr->notifier_last)) {
> +		pr_debug("userptr: [%llx-%llx], resid: %d check range failed\n",
> +			 userptr->userptr_start, userptr->userptr_last,
> +			 userptr->base.hw_res_handle);
> +		/* add to work list or process here directly, add to work list here */
> +		virtio_gpu_update_or_remove_userptr(
> +			userptr, userptr->notifier_start,
> +			userptr->notifier_last + (1UL << PAGE_SHIFT) - 1UL);
> +	}
> +
> +	userptr->notifier_start = 0;
> +	userptr->notifier_last = 0;
> +}
> +
> +static void
> +virtio_gpu_userptr_handle_list_work(struct virtio_gpu_object_userptr *userptr)
> +{
> +	switch (userptr->op) {
> +	case USERPTR_OP_NULL:
> +		break;
> +	case USERPTR_OP_UNMAP:
> +		virtio_gpu_userptr_unmap(userptr);
> +		break;
> +	case USERPTR_OP_UPDATE:
> +		virtio_gpu_userptr_update_notifier_and_interval_tree(userptr);
> +		break;
> +	case USERPTR_OP_EVICT:
> +		virtio_gpu_userptr_evict(userptr);
> +		break;
> +	default:
> +		break;
> +	}
> +}
> +
> +static void virtio_gpu_userptr_invalidate_work(struct work_struct *work)
> +{
> +	struct virtio_gpu_fpriv *vfpriv;
> +	struct virtio_gpu_object_userptr *userptr;
> +	struct mm_struct *mm;
> +
> +	vfpriv = container_of(work, struct virtio_gpu_fpriv,
> +			      userptr_invalidate_work);
> +
> +	spin_lock(&vfpriv->userptr_invalidate_list_lock);
> +	while (!list_empty(&vfpriv->userptr_invalidate_list)) {
> +		userptr = list_first_entry(&vfpriv->userptr_invalidate_list,
> +					   struct virtio_gpu_object_userptr,
> +					   work_list);
> +		spin_unlock(&vfpriv->userptr_invalidate_list_lock);
> +
> +		mm = userptr->mm;
> +
> +		mmap_write_lock(mm);
> +
> +		/* Remove from userptr_invalidate_list_lock must inside mmap write lock, cause:
> +		 * after remove from list, the work_item.op may be changed by other thread
> +		 * like MMU notifier invalidate callback, and maybe add the userptr to work
> +		 * list again.
> +		 * What will cause use after free or double free bug.
> +		 * So need use mmap_write_lock to prevent the invalidate callback triggering then
> +		 * remove the from work list to snsure one work item only be handled once.
> +		 */
> +		spin_lock(&vfpriv->userptr_invalidate_list_lock);
> +		list_del_init(&userptr->work_list);
> +		spin_unlock(&vfpriv->userptr_invalidate_list_lock);
> +
> +		mutex_lock(&vfpriv->userptrs_tree_lock);
> +
> +		virtio_gpu_userptr_handle_list_work(userptr);
> +
> +		mutex_unlock(&vfpriv->userptrs_tree_lock);
> +		mmap_write_unlock(mm);
> +
> +		spin_lock(&vfpriv->userptr_invalidate_list_lock);
> +	}
> +	spin_unlock(&vfpriv->userptr_invalidate_list_lock);
> +}
> +
> +void virtio_gpu_userptr_list_work_init(struct virtio_gpu_fpriv *vfpriv)
> +{
> +	INIT_WORK(&vfpriv->userptr_invalidate_work,
> +		  virtio_gpu_userptr_invalidate_work);
> +	INIT_LIST_HEAD(&vfpriv->userptr_invalidate_list);
> +	spin_lock_init(&vfpriv->userptr_invalidate_list_lock);
> +}
> +
> +static void
> +virtio_gpu_userptr_schedule_list_work(struct virtio_gpu_fpriv *vfpriv)
> +{
> +	spin_lock(&vfpriv->userptr_invalidate_list_lock);
> +	if (!list_empty(&vfpriv->userptr_invalidate_list))
> +		schedule_work(&vfpriv->userptr_invalidate_work);
> +	spin_unlock(&vfpriv->userptr_invalidate_list_lock);
> +}
> +
> +static void virtio_gpu_object_userptr_remove_within_range(
> +	struct virtio_gpu_fpriv *vfpriv, u_int64_t start, u_int64_t last,
> +	bool check_start, const char *from)
> +{
> +	struct interval_tree_node *node;
> +	struct virtio_gpu_object_userptr *userptr = NULL;
> +	uint64_t remove_userptr_size = last - start + 1UL;
> +	uint64_t userptr_size;
> +
> +	mutex_lock(&vfpriv->userptrs_tree_lock);
> +
> +	node = interval_tree_iter_first(&vfpriv->userptrs_tree, start, last);
> +
> +	while (node) {
> +		struct interval_tree_node *next;
> +
> +		userptr = container_of(node, struct virtio_gpu_object_userptr,
> +				       it_node);
> +
> +		userptr_size =
> +			userptr->userptr_last - userptr->userptr_start + 1UL;
> +		if (userptr->userptr_start >= start &&
> +		    userptr->userptr_last < last) {
> +			if ((!check_start) ||
> +			    (check_start && userptr->userptr_start == start)) {
> +				if (atomic_xchg(&userptr->in_release, 1) == 0 &&
> +				    !userptr->op) {
> +					userptr->mm = current->mm;
> +					virtio_gpu_userptr_add_list_work(
> +						userptr, USERPTR_OP_UNMAP);
> +				}
> +			}
> +		}
> +
> +		next = interval_tree_iter_next(node, start, last);
> +		node = next;
> +	}
> +	mutex_unlock(&vfpriv->userptrs_tree_lock);
> +
> +	virtio_gpu_userptr_schedule_list_work(userptr->file->driver_priv);
> +}
> +
> +static bool
> +virtio_gpu_userptr_invalidate(struct mmu_interval_notifier *mn,
> +			      const struct mmu_notifier_range *range,
> +			      unsigned long cur_seq)
> +{
> +	struct virtio_gpu_object_userptr *userptr;
> +	struct virtio_gpu_fpriv *vfpriv;
> +	unsigned long start;
> +	unsigned long last;
> +
> +	if (range->event == MMU_NOTIFY_RELEASE)
> +		return true;
> +	if (!mmget_not_zero(mn->mm))
> +		return true;
> +
> +	start = mn->interval_tree.start;
> +	last = mn->interval_tree.last;
> +	start = (max(start, range->start) >> PAGE_SHIFT) << PAGE_SHIFT;
> +	last = (min(last, range->end - 1UL) >> PAGE_SHIFT) << PAGE_SHIFT;
> +
> +	userptr = container_of(mn, struct virtio_gpu_object_userptr, notifier);
> +	userptr->mm = mn->mm;
> +	vfpriv = userptr->file->driver_priv;
> +
> +	mutex_lock(&userptr->lock);
> +	mmu_interval_set_seq(mn, cur_seq);
> +
> +	pr_debug(
> +		"userptr: [%llx-%llx]-%llx notifier: [%lx-%lx]-%lx check: [%lx-%lx]-%lx resid: %d event: %d\n",
> +		userptr->userptr_start, userptr->userptr_last,
> +		userptr->userptr_last - userptr->userptr_start + 1UL,
> +		range->start, range->end - 1UL, range->end - range->start,
> +		start, last, last - start + (1UL << PAGE_SHIFT),
> +		userptr->base.hw_res_handle, range->event);
> +
> +	if (userptr->op == USERPTR_OP_UNMAP) {
> +		pr_debug(
> +			"userptr: [%llx-%llx] resid: %d already in unmap op: %d\n",
> +			userptr->userptr_start, userptr->userptr_last,
> +			userptr->base.hw_res_handle, userptr->op);
> +	} else {
> +		switch (range->event) {
> +		case MMU_NOTIFY_UNMAP:
> +			virtio_gpu_update_or_remove_userptr(
> +				userptr, start,
> +				last + (1UL << PAGE_SHIFT) - 1UL);
> +			break;
> +		default:
> +			userptr->notifier_start = start;
> +			userptr->notifier_last = last;
> +			virtio_gpu_userptr_add_list_work(userptr,
> +							 USERPTR_OP_EVICT);
> +			break;
> +		}
> +	}
> +
> +	virtio_gpu_userptr_schedule_list_work(userptr->file->driver_priv);
> +
> +	mutex_unlock(&userptr->lock);
> +	mmput(mn->mm);
> +	return true;
> +}
> +
> +static void
> +virtio_gpu_userptr_lock_and_flush_work(struct virtio_gpu_fpriv *vfpriv,
> +				       struct mm_struct *mm)
> +{
> +retry_flush_work:
> +	flush_work(&vfpriv->userptr_invalidate_work);
> +
> +	if (list_empty(&vfpriv->userptr_invalidate_list))
> +		return;
> +
> +	goto retry_flush_work;
> +}
> +
> +void virtio_gpu_userptr_set_handle(struct virtio_gpu_object *qobj,
> +				   uint32_t handle)
> +{
> +	struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(qobj);
> +
> +	userptr->bo_handle = handle;
> +	virtio_gpu_object_userptr_remove_within_range(
> +		userptr->file->driver_priv, userptr->userptr_start,
> +		userptr->userptr_last, false, __func__);
> +	virtio_gpu_userptr_add_notifier(userptr, userptr->userptr_start,
> +					userptr->npages << PAGE_SHIFT);
> +}
> +
> +static int virtio_gpu_userptr_init(struct drm_device *dev,
> +				   struct drm_file *file,
> +				   struct drm_gem_object *obj,
> +				   struct virtio_gpu_object_params *params,
> +				   unsigned long **p_pfns, uint32_t *p_npfns)
> +{
> +	struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
> +	struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(bo);
> +	unsigned long page_offset;
> +	unsigned long aligned_size;
> +	struct page **pages;
> +	unsigned int pinned = 0;
> +	uint64_t aligned_addr;
> +	int ret;
> +
> +	page_offset = (uint64_t)params->blob_userptr & (PAGE_SIZE - 1UL);
> +	aligned_addr = params->blob_userptr - page_offset;
> +	aligned_size = roundup(page_offset + params->size, PAGE_SIZE);
> +
> +	pr_debug(
> +		"create userptr addr: %llx size: %lx, aligned: [%llx-%llx]-%lx\n",
> +		params->blob_userptr, params->size, aligned_addr,
> +		aligned_addr + aligned_size - 1UL, aligned_size);
> +
> +	params->size = aligned_size;
> +
> +	drm_gem_private_object_init(dev, obj, aligned_size);
> +
> +	*p_npfns = aligned_size / PAGE_SIZE;
> +	*p_pfns = vmalloc(*p_npfns * sizeof(unsigned long));
> +	if (!(*p_pfns)) {
> +		pr_err("failed to allocate userptr pfns\n");
> +		return -ENOMEM;
> +	}
> +
> +	pages = vmalloc(*p_npfns * sizeof(struct page *));
> +	if (!pages)
> +		return -ENOMEM;
> +
> +	userptr->userptr_inital_start = aligned_addr;
> +	userptr->userptr_start = aligned_addr;
> +	userptr->userptr_last = userptr->userptr_start + aligned_size - 1UL;
> +
> +	do {
> +		unsigned int num_pages = *p_npfns - pinned;
> +		uint64_t ptr = userptr->userptr_start + pinned * PAGE_SIZE;
> +		struct page **pinned_pages = pages + pinned;
> +
> +		ret = pin_user_pages_fast(
> +			ptr, num_pages, FOLL_WRITE | FOLL_FORCE, pinned_pages);
> +
> +		if (ret < 0) {
> +			pr_err("pin memory failed, addr: 0x%llx\n",
> +			       userptr->userptr_start);
> +			if (pinned && pages)
> +				unpin_user_pages(pages, pinned);
> +			userptr->userptr_start = 0;
> +			vfree(pages);
> +			vfree(*p_pfns);
> +			return -ENOMEM;
> +		}
> +
> +		pinned += ret;
> +
> +	} while (pinned < *p_npfns);
> +
> +	userptr->pages = pages;
> +	userptr->npages = *p_npfns;
> +	bo->base.base.size = aligned_size;
> +
> +	for (int i = 0; i < (*p_npfns); i++)
> +		(*p_pfns)[i] = page_to_pfn(pages[i]);
> +
> +	atomic_set(&userptr->in_release, 0);
> +	INIT_LIST_HEAD(&userptr->work_list);
> +	mutex_init(&userptr->lock);
> +	userptr->vgdev = dev->dev_private;
> +	userptr->file = file;
> +
> +	return 0;
> +}
> +
> +int virtio_gpu_userptr_create(struct virtio_gpu_device *vgdev,
> +			      struct drm_file *file,
> +			      struct virtio_gpu_object_params *params,
> +			      struct virtio_gpu_object **bo_ptr)
> +{
> +	struct mm_struct *mm = current->mm;
> +	struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
> +	struct drm_gem_object *obj;
> +	struct virtio_gpu_object_userptr *userptr;
> +	int ret;
> +	unsigned long *pfns;
> +	uint32_t npfns;
> +
> +	virtio_gpu_userptr_lock_and_flush_work(vfpriv, mm);
> +
> +	mutex_lock(&vfpriv->userptrs_tree_lock);
> +	userptr = virtio_gpu_userptr_from_addr_range(
> +		vfpriv, params->blob_userptr,
> +		params->blob_userptr + params->size - 1UL);
> +	if (userptr) {
> +		*bo_ptr = &userptr->base;
> +		mutex_unlock(&vfpriv->userptrs_tree_lock);
> +		return USERPTR_EXISTS;
> +	}
> +
> +	userptr = kzalloc(sizeof(*userptr), GFP_KERNEL);
> +	if (!userptr)
> +		return -ENOMEM;
> +
> +	obj = &userptr->base.base.base;
> +	obj->funcs = &virtio_gpu_userptr_funcs;
> +
> +	ret = virtio_gpu_userptr_init(vgdev->ddev, file, obj, params, &pfns,
> +				      &npfns);
> +	if (ret)
> +		goto failed_free;
> +
> +	ret = virtio_gpu_resource_id_get(vgdev, &userptr->base.hw_res_handle);
> +	if (ret)
> +		goto failed_free;
> +
> +	virtio_gpu_userptr_add_interval_tree(vfpriv, userptr);
> +	/* virtio_gpu_userptr_dump(vfpriv); */
> +
> +	mutex_unlock(&vfpriv->userptrs_tree_lock);
> +
> +	virtio_gpu_cmd_resource_create_userptr(vgdev, &userptr->base, params,
> +					       pfns, npfns);
> +
> +	*bo_ptr = &userptr->base;
> +	return 0;
> +
> +failed_free:
> +	mutex_unlock(&vfpriv->userptrs_tree_lock);
> +	kfree(userptr);
> +	return ret;
> +}
> diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
> index 29d462b69bad..2699b85829f4 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_vq.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
> @@ -1270,6 +1270,35 @@ virtio_gpu_cmd_resource_create_blob(struct virtio_gpu_device *vgdev,
>  	bo->created = true;
>  }
>  
> +void
> +virtio_gpu_cmd_resource_create_userptr(struct virtio_gpu_device *vgdev,
> +				    struct virtio_gpu_object *bo,
> +				    struct virtio_gpu_object_params *params,
> +				    unsigned long *pfns,
> +				    uint32_t npfns)
> +{
> +	struct virtio_gpu_resource_create_blob *cmd_p;
> +	struct virtio_gpu_vbuffer *vbuf;
> +
> +	cmd_p = virtio_gpu_alloc_cmd(vgdev, &vbuf, sizeof(*cmd_p));
> +	memset(cmd_p, 0, sizeof(*cmd_p));
> +
> +	cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_CREATE_BLOB);
> +	cmd_p->hdr.ctx_id = cpu_to_le32(params->ctx_id);
> +	cmd_p->resource_id = cpu_to_le32(bo->hw_res_handle);
> +	cmd_p->blob_mem = cpu_to_le32(params->blob_mem);
> +	cmd_p->blob_flags = cpu_to_le32(params->blob_flags);
> +	cmd_p->blob_id = cpu_to_le64(params->blob_id);
> +	cmd_p->size = cpu_to_le64(params->size);
> +	cmd_p->nr_entries = cpu_to_le32(npfns);
> +
> +	vbuf->data_buf = pfns;
> +	vbuf->data_size = sizeof(*pfns) * npfns;
> +
> +	virtio_gpu_queue_ctrl_buffer(vgdev, vbuf);
> +	bo->created = true;
> +}
> +
>  void virtio_gpu_cmd_set_scanout_blob(struct virtio_gpu_device *vgdev,
>  				     uint32_t scanout_id,
>  				     struct virtio_gpu_object *bo,
> -- 
> 2.34.1
>

Demi Marie Obenour Dec. 22, 2024, 1:59 a.m. UTC | #2

On 12/20/24 10:35 AM, Simona Vetter wrote:
> On Fri, Dec 20, 2024 at 06:04:09PM +0800, Honglei Huang wrote:
>> From: Honglei Huang <[e-mail]>
>>
>> A virtio-gpu userptr is based on HMM notifier.
>> Used for let host access guest userspace memory and
>> notice the change of userspace memory.
>> This series patches are in very beginning state,
>> User space are pinned currently to ensure the host
>> device memory operations are correct.
>> The free and unmap operations for userspace can be
>> handled by MMU notifier this is a simple and basice
>> SVM feature for this series patches.
>> The physical PFNS update operations is splited into
>> two OPs in here. The evicted memories won't be used
>> anymore but remap into host again to achieve same
>> effect with hmm_rang_fault.
> 
> So in my opinion there are two ways to implement userptr that make sense:
> 
> - pinned userptr with pin_user_pages(FOLL_LONGTERM). there is not mmu
>   notifier
> 
> - unpinnned userptr where you entirely rely on userptr and do not hold any
>   page references or page pins at all, for full SVM integration. This
>   should use hmm_range_fault ideally, since that's the version that
>   doesn't ever grab any page reference pins.
> 
> All the in-between variants are imo really bad hacks, whether they hold a
> page reference or a temporary page pin (which seems to be what you're
> doing here). In much older kernels there was some justification for them,
> because strange stuff happened over fork(), but with FOLL_LONGTERM this is
> now all sorted out. So there's really only fully pinned, or true svm left
> as clean design choices imo.
> 
> With that background, why does pin_user_pages(FOLL_LONGTERM) not work for
> you?

+1 on using FOLL_LONGTERM.  Fully dynamic memory management has a huge cost
in complexity that pinning everything avoids.  Furthermore, this avoids the
host having to take action in response to guest memory reclaim requests.
This avoids additional complexity (and thus attack surface) on the host side.
Furthermore, since this is for ROCm and not for graphics, I am less concerned
about supporting systems that require swappable GPU VRAM.

Patch

diff --git a/drivers/gpu/drm/virtio/Makefile b/drivers/gpu/drm/virtio/Makefile
index d2e1788a8227..351c45e1e7d1 100644
--- a/drivers/gpu/drm/virtio/Makefile
+++ b/drivers/gpu/drm/virtio/Makefile
@@ -2,8 +2,9 @@ 
 #
 # Makefile for the drm device driver.  This driver provides support for the
 # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
+# virtgpu_userptr.o
 
-virtio-gpu-y := virtgpu_drv.o virtgpu_kms.o virtgpu_gem.o virtgpu_vram.o \
+virtio-gpu-y := virtgpu_drv.o virtgpu_kms.o virtgpu_gem.o virtgpu_vram.o virtgpu_userptr.o \
 	virtgpu_display.o virtgpu_vq.o \
 	virtgpu_fence.o virtgpu_object.o virtgpu_debugfs.o virtgpu_plane.o \
 	virtgpu_ioctl.o virtgpu_prime.o virtgpu_trace_points.o virtgpu_submit.o
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index e1ee17466f6b..5d15c018201d 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -31,6 +31,8 @@ 
 #include <linux/virtio_ids.h>
 #include <linux/virtio_config.h>
 #include <linux/virtio_gpu.h>
+#include <linux/mmu_notifier.h>
+#include <linux/rbtree_types.h>
 
 #include <drm/drm_atomic.h>
 #include <drm/drm_drv.h>
@@ -85,6 +87,7 @@  struct virtio_gpu_object_params {
 	uint32_t blob_mem;
 	uint32_t blob_flags;
 	uint64_t blob_id;
+	uint64_t blob_userptr;
 };
 
 struct virtio_gpu_object {
@@ -112,12 +115,50 @@  struct virtio_gpu_object_vram {
 	struct drm_mm_node vram_node;
 };
 
+enum userptr_work_list_ops {
+	USERPTR_OP_NULL,
+	USERPTR_OP_UNMAP,
+	USERPTR_OP_UPDATE,
+	USERPTR_OP_EVICT,
+};
+
+struct virtio_gpu_object_userptr {
+	struct virtio_gpu_object base;
+
+	struct page **pages;
+	uint64_t userptr_inital_start;
+	uint64_t userptr_start;
+	uint64_t userptr_last;
+	uint32_t npages;
+	uint32_t bo_handle;
+	struct list_head work_list;
+	struct virtio_gpu_device *vgdev;
+	struct mmu_interval_notifier notifier;
+	struct drm_file *file;
+
+	/* for list work */
+	struct mm_struct *mm;
+	enum userptr_work_list_ops op;
+	uint64_t notifier_start;
+	uint64_t notifier_last;
+
+	/* userptr interval tree node */
+	struct interval_tree_node it_node;
+
+	/* in release list work queue */
+	atomic_t in_release;
+	struct mutex lock;
+};
+
 #define to_virtio_gpu_shmem(virtio_gpu_object) \
 	container_of((virtio_gpu_object), struct virtio_gpu_object_shmem, base)
 
 #define to_virtio_gpu_vram(virtio_gpu_object) \
 	container_of((virtio_gpu_object), struct virtio_gpu_object_vram, base)
 
+#define to_virtio_gpu_userptr(virtio_gpu_object) \
+	container_of((virtio_gpu_object), struct virtio_gpu_object_userptr, base)
+
 struct virtio_gpu_object_array {
 	struct ww_acquire_ctx ticket;
 	struct list_head next;
@@ -279,6 +320,16 @@  struct virtio_gpu_fpriv {
 	uint64_t base_fence_ctx;
 	uint64_t ring_idx_mask;
 	struct mutex context_lock;
+
+	/* for userptr mmu notifier invalidate */
+	struct work_struct userptr_invalidate_work;
+	struct list_head userptr_invalidate_list;
+	spinlock_t userptr_invalidate_list_lock;
+
+	/* userptr interval tree */
+	struct rb_root_cached userptrs_tree;
+	struct mutex userptrs_tree_lock;
+
 	char debug_name[DEBUG_NAME_MAX_LEN];
 	bool explicit_debug_name;
 	bool fence_passing_enabled;
@@ -422,6 +473,14 @@  virtio_gpu_cmd_resource_create_blob(struct virtio_gpu_device *vgdev,
 				    struct virtio_gpu_object_params *params,
 				    struct virtio_gpu_mem_entry *ents,
 				    uint32_t nents);
+
+void
+virtio_gpu_cmd_resource_create_userptr(struct virtio_gpu_device *vgdev,
+				    struct virtio_gpu_object *bo,
+				    struct virtio_gpu_object_params *params,
+				    unsigned long *pfns,
+				    uint32_t npfns);
+
 void
 virtio_gpu_cmd_set_scanout_blob(struct virtio_gpu_device *vgdev,
 				uint32_t scanout_id,
@@ -497,4 +556,17 @@  void virtio_gpu_vram_unmap_dma_buf(struct device *dev,
 int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
 				struct drm_file *file);
 
+/* virtgpu_userptr.c */
+void virtio_gpu_userptr_set_handle(struct virtio_gpu_object *qobj,
+				   uint32_t handle);
+uint32_t virtio_gpu_userptr_get_handle(struct virtio_gpu_object *qobj);
+void virtio_gpu_userptr_list_work_init(struct virtio_gpu_fpriv *vfpriv);
+void virtio_gpu_userptr_interval_tree_init(struct virtio_gpu_fpriv *vfpriv);
+uint64_t virtio_gpu_userptr_get_offset(struct virtio_gpu_object *qobj,
+				       uint64_t addr);
+bool virtio_gpu_is_userptr(struct virtio_gpu_object *bo);
+int virtio_gpu_userptr_create(struct virtio_gpu_device *vgdev,
+			      struct drm_file *file,
+			      struct virtio_gpu_object_params *params,
+			      struct virtio_gpu_object **bo_ptr);
 #endif
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index d40c7402720d..519278443c66 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -36,7 +36,8 @@ 
 
 #define VIRTGPU_BLOB_FLAG_USE_MASK (VIRTGPU_BLOB_FLAG_USE_MAPPABLE | \
 				    VIRTGPU_BLOB_FLAG_USE_SHAREABLE | \
-				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE)
+				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE | \
+				    VIRTGPU_BLOB_FLAG_USE_USERPTR)
 
 /* Must be called with &virtio_gpu_fpriv.struct_mutex held. */
 static void virtio_gpu_create_context_locked(struct virtio_gpu_device *vgdev,
@@ -489,6 +490,7 @@  static int verify_blob(struct virtio_gpu_device *vgdev,
 	params->size = rc_blob->size;
 	params->blob = true;
 	params->blob_flags = rc_blob->blob_flags;
+	params->blob_userptr = rc_blob->blob_userptr;
 	return 0;
 }
 
@@ -528,8 +530,20 @@  static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
 				      rc_blob->cmd_size, 0);
 	}
 
-	if (guest_blob)
+	if (guest_blob && !params.blob_userptr)
 		ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
+	else if (guest_blob && params.blob_userptr) {
+		ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);
+		if (unlikely(ret < 0))
+			return ret;
+		if (ret > 0) {
+			/* userptr already exist */
+			rc_blob->res_handle = bo->hw_res_handle;
+			rc_blob->bo_handle = virtio_gpu_userptr_get_handle(bo);
+			rc_blob->offset = virtio_gpu_userptr_get_offset(bo, rc_blob->blob_userptr);
+			return ret;
+		}
+	}
 	else if (!guest_blob && host3d_blob)
 		ret = virtio_gpu_vram_create(vgdev, &params, &bo);
 	else
@@ -560,6 +574,9 @@  static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
 
 	rc_blob->res_handle = bo->hw_res_handle;
 	rc_blob->bo_handle = handle;
+	/* for mmu notifier auto release */
+	if (guest_blob && params.blob_userptr)
+		virtio_gpu_userptr_set_handle(bo, handle);
 
 	/*
 	 * The handle owns the reference now.  But we must drop our
@@ -691,6 +708,10 @@  static int virtio_gpu_context_init_ioctl(struct drm_device *dev,
 			goto out_unlock;
 		}
 	}
+	if (vfpriv->context_init & VIRTIO_GPU_CAPSET_HSAKMT) {
+		virtio_gpu_userptr_list_work_init(vfpriv);
+		virtio_gpu_userptr_interval_tree_init(vfpriv);
+	}
 
 	virtio_gpu_create_context_locked(vgdev, vfpriv);
 	virtio_gpu_notify(vgdev);
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 9f4617a75edd..3af40ed8936a 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -346,6 +346,8 @@  void virtio_gpu_driver_postclose(struct drm_device *dev, struct drm_file *file)
 		return;
 
 	if (vfpriv->context_created) {
+		if (vfpriv->context_init & VIRTIO_GPU_CAPSET_HSAKMT)
+			flush_work(&vfpriv->userptr_invalidate_work);
 		virtio_gpu_cmd_context_destroy(vgdev, vfpriv->ctx_id);
 		virtio_gpu_notify(vgdev);
 	}
diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index c7e74cf13022..31659b0a028d 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -80,6 +80,11 @@  void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo)
 		drm_gem_free_mmap_offset(&vram->base.base.base);
 		drm_gem_object_release(&vram->base.base.base);
 		kfree(vram);
+	} else if (virtio_gpu_is_userptr(bo)) {
+		struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(bo);
+
+		drm_gem_object_release(&userptr->base.base.base);
+		kfree(userptr);
 	}
 }
 
diff --git a/drivers/gpu/drm/virtio/virtgpu_userptr.c b/drivers/gpu/drm/virtio/virtgpu_userptr.c
new file mode 100644
index 000000000000..646088f7f72b
--- /dev/null
+++ b/drivers/gpu/drm/virtio/virtgpu_userptr.c
@@ -0,0 +1,738 @@ 
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+#include "virtgpu_drv.h"
+
+#include <linux/dma-mapping.h>
+
+#include <linux/mm.h>
+#include <linux/pid.h>
+
+#include "drm/drm_gem.h"
+
+#include <linux/mmu_notifier.h>
+
+#define USERPTR_PFNS_NO_CHANGE 0
+#define USERPTR_PFNS_CHANGED 1
+#define USERPTR_PFNS_NONE 2
+
+#define USERPTR_EXISTS 1
+
+static bool
+virtio_gpu_userptr_invalidate(struct mmu_interval_notifier *mn,
+			      const struct mmu_notifier_range *range,
+			      unsigned long cur_seq);
+
+static const struct mmu_interval_notifier_ops virtio_gpu_userptr_mn_ops = {
+	.invalidate = virtio_gpu_userptr_invalidate,
+};
+
+static void virtio_gpu_userptr_unlink(struct virtio_gpu_fpriv *vfpriv,
+				      struct virtio_gpu_object_userptr *userptr)
+{
+	if (userptr->it_node.start != 0 && userptr->it_node.last != 0)
+		interval_tree_remove(&userptr->it_node, &vfpriv->userptrs_tree);
+}
+
+static void virtio_gpu_userptr_free(struct drm_gem_object *obj)
+{
+	struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
+	struct virtio_gpu_device *vgdev = obj->dev->dev_private;
+	struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(bo);
+
+	if (bo->created) {
+		unpin_user_pages_dirty_lock(userptr->pages, userptr->npages,
+					    false);
+		vfree(userptr->pages);
+		userptr->pages = NULL;
+
+		virtio_gpu_cmd_unref_resource(vgdev, bo);
+		virtio_gpu_notify(vgdev);
+
+		return;
+	}
+}
+
+static void virtio_gpu_userptr_object_close(struct drm_gem_object *obj,
+					    struct drm_file *file)
+{
+	virtio_gpu_gem_object_close(obj, file);
+}
+
+static const struct drm_gem_object_funcs virtio_gpu_userptr_funcs = {
+	.open = virtio_gpu_gem_object_open,
+	.close = virtio_gpu_userptr_object_close,
+	.free = virtio_gpu_userptr_free,
+};
+
+bool virtio_gpu_is_userptr(struct virtio_gpu_object *bo)
+{
+	return bo->base.base.funcs == &virtio_gpu_userptr_funcs;
+}
+
+static int
+virtio_gpu_userptr_add_notifier(struct virtio_gpu_object_userptr *userptr,
+				unsigned long start, unsigned long length)
+{
+	int ret = mmu_interval_notifier_insert_locked(
+		&userptr->notifier, current->mm, start, length,
+		&virtio_gpu_userptr_mn_ops);
+
+	if (ret)
+		pr_err("mmu_interval_notifier_insert_locked failed ret: %d\n",
+		       ret);
+	return ret;
+}
+
+uint32_t virtio_gpu_userptr_get_handle(struct virtio_gpu_object *qobj)
+{
+	struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(qobj);
+
+	return userptr->bo_handle;
+}
+
+uint64_t virtio_gpu_userptr_get_offset(struct virtio_gpu_object *qobj,
+				       uint64_t addr)
+{
+	struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(qobj);
+	uint64_t userptr_align_down = ALIGN_DOWN(addr, PAGE_SIZE);
+	uint64_t offset = userptr_align_down - userptr->userptr_inital_start;
+	return offset;
+}
+
+void virtio_gpu_userptr_interval_tree_init(struct virtio_gpu_fpriv *vfpriv)
+{
+	vfpriv->userptrs_tree = RB_ROOT_CACHED;
+	mutex_init(&vfpriv->userptrs_tree_lock);
+}
+
+static struct virtio_gpu_object_userptr *
+virtio_gpu_userptr_from_addr_range(struct virtio_gpu_fpriv *vfpriv,
+				   u_int64_t start, u_int64_t last)
+{
+	struct interval_tree_node *node;
+	struct virtio_gpu_object_userptr *userptr = NULL;
+	struct virtio_gpu_object_userptr *ret = NULL;
+	uint64_t userptr_size;
+
+	node = interval_tree_iter_first(&vfpriv->userptrs_tree, start, last);
+
+	while (node) {
+		struct interval_tree_node *next;
+
+		userptr = container_of(node, struct virtio_gpu_object_userptr,
+				       it_node);
+
+		if (start >= userptr->userptr_start &&
+		    last <= userptr->userptr_last &&
+		    !atomic_read(&userptr->in_release) && !userptr->op) {
+			ret = userptr;
+			userptr_size = userptr->userptr_last -
+				       userptr->userptr_start + 1UL;
+			return ret;
+		}
+
+		next = interval_tree_iter_next(node, start, last);
+		node = next;
+	}
+
+	return ret;
+}
+
+static void
+virtio_gpu_userptr_add_interval_tree(struct virtio_gpu_fpriv *vfpriv,
+				     struct virtio_gpu_object_userptr *userptr)
+{
+	userptr->it_node.start = userptr->userptr_start;
+	userptr->it_node.last = userptr->userptr_last;
+	interval_tree_insert(&userptr->it_node, &vfpriv->userptrs_tree);
+}
+
+static void virtio_gpu_userptr_unmap(struct virtio_gpu_object_userptr *userptr)
+{
+	pr_debug(
+		"list work remove userptr: [%llx-%llx], resid: %d bo_handle: %d size: %x\n",
+		userptr->userptr_start, userptr->userptr_last,
+		userptr->base.hw_res_handle, userptr->bo_handle,
+		userptr->npages);
+
+	virtio_gpu_userptr_unlink(userptr->file->driver_priv, userptr);
+	mmu_interval_notifier_remove(&userptr->notifier);
+
+	drm_gem_handle_delete(userptr->file, userptr->bo_handle);
+}
+
+static void virtio_gpu_userptr_update_notifier_and_interval_tree(
+	struct virtio_gpu_object_userptr *userptr)
+{
+	unsigned long start = userptr->notifier.interval_tree.start;
+	unsigned long last = userptr->notifier.interval_tree.last;
+
+	if (userptr->userptr_start == start && userptr->userptr_last == last)
+		return;
+
+	if (start != 0 && last != 0) {
+		virtio_gpu_userptr_unlink(userptr->file->driver_priv, userptr);
+		mmu_interval_notifier_remove(&userptr->notifier);
+	}
+
+	pr_debug(
+		"update userptr: [%lx-%lx]-%lx -> [%llx-%llx]-%llx resid: %d\n",
+		start, last, last - start + 1UL, userptr->userptr_start,
+		userptr->userptr_last,
+		userptr->userptr_last - userptr->userptr_start + 1UL,
+		userptr->base.hw_res_handle);
+
+	virtio_gpu_userptr_add_interval_tree(userptr->file->driver_priv,
+					     userptr);
+	mmu_interval_notifier_insert_locked(
+		&userptr->notifier, userptr->mm, userptr->userptr_start,
+		userptr->userptr_last - userptr->userptr_start + 1UL,
+		&virtio_gpu_userptr_mn_ops);
+
+	userptr->op = 0;
+}
+
+static int virtio_gpu_userptr_split(struct virtio_gpu_object_userptr *userptr,
+				    unsigned long valid_start,
+				    unsigned long valid_last,
+				    struct virtio_gpu_object_userptr **new)
+{
+	uint64_t old_start = userptr->userptr_start;
+	uint64_t old_last = userptr->userptr_last;
+
+	if (old_start != valid_start && old_last != valid_last)
+		return -EINVAL;
+	if (valid_start < old_start || valid_last > old_last)
+		return -EINVAL;
+
+	/* split new userptr is not needed currently, but keep the API parameters here
+	 * for future expansion.
+	 */
+	*new = NULL;
+
+	/* update range */
+	userptr->userptr_start = valid_start;
+	userptr->userptr_last = valid_last;
+
+	return 0;
+}
+
+static void
+virtio_gpu_userptr_update_split(struct virtio_gpu_object_userptr *userptr,
+				unsigned long mn_start, unsigned long mn_last)
+{
+	struct virtio_gpu_object_userptr *head;
+	struct virtio_gpu_object_userptr *tail;
+
+	if (userptr->op == USERPTR_OP_UNMAP)
+		return;
+
+	if (mn_start > userptr->userptr_last ||
+	    mn_last < userptr->userptr_start)
+		return;
+
+	head = tail = userptr;
+	if (mn_start > userptr->userptr_start)
+		virtio_gpu_userptr_split(userptr, userptr->userptr_start,
+					 mn_start - 1UL, &tail);
+	else if (mn_last < userptr->userptr_last)
+		virtio_gpu_userptr_split(userptr, mn_last + 1UL,
+					 userptr->userptr_last, &head);
+
+	/* split tail maybe not needed in virtgpu */
+	/* if (mn_last < userptr->userptr_last) */
+	/* add child userptr maybe not needed in virtgpu */
+}
+
+static void
+virtio_gpu_userptr_add_list_work(struct virtio_gpu_object_userptr *userptr,
+				 int op)
+{
+	struct virtio_gpu_fpriv *vfpriv = userptr->file->driver_priv;
+
+	spin_lock(&vfpriv->userptr_invalidate_list_lock);
+
+	if (!list_empty(&userptr->work_list)) {
+		pr_debug(
+			"update exist userptr userptr: [%llx-%llx] work op to %d\n",
+			userptr->userptr_start, userptr->userptr_last, op);
+		if (op != USERPTR_OP_NULL && userptr->op != USERPTR_OP_UNMAP)
+			userptr->op = op;
+	} else {
+		userptr->op = op;
+		list_add_tail(&userptr->work_list,
+			      &vfpriv->userptr_invalidate_list);
+	}
+
+	spin_unlock(&vfpriv->userptr_invalidate_list_lock);
+}
+
+static int
+virtio_gpu_userptr_check_pfns(struct virtio_gpu_object_userptr *userptr,
+			      struct vm_area_struct *vma, uint64_t start,
+			      uint64_t end)
+{
+	uint64_t addr;
+	int ret;
+	unsigned long pfn;
+	spinlock_t *ptl;
+	pte_t *ptep;
+
+	for (addr = start; addr < end; addr += PAGE_SIZE) {
+		ret = follow_pte(vma->vm_mm, addr, &ptep, &ptl);
+		if (ret) {
+			pr_debug("follow_pfn in userptr failed, addr: %llx\n",
+				 addr);
+			return USERPTR_PFNS_NONE;
+		}
+		pfn = pte_pfn(ptep_get(ptep));
+		pte_unmap_unlock(ptep, ptl);
+		if (page_to_pfn(
+			    userptr->pages[(addr - userptr->userptr_start) >>
+					   PAGE_SHIFT]) != pfn) {
+			pr_debug("userptr pages not match, addr: %llx\n", addr);
+			return USERPTR_PFNS_CHANGED;
+		}
+	}
+
+	return USERPTR_PFNS_NO_CHANGE;
+}
+
+static int
+virtio_gpu_userptr_check_range(struct virtio_gpu_object_userptr *userptr,
+			       uint64_t notifier_start, uint64_t notifier_last)
+{
+	uint64_t start, end, addr;
+	int r = 0;
+
+	start = notifier_start;
+	end = notifier_last + (1UL << PAGE_SHIFT);
+
+	for (addr = start; !r && addr < end;) {
+		struct vm_area_struct *vma;
+		uint64_t next = 0;
+		uint32_t npages;
+
+		vma = vma_lookup(userptr->mm, addr);
+
+		if (vma) {
+			next = min(vma->vm_end, end);
+			npages = (next - addr) >> PAGE_SHIFT;
+			r = virtio_gpu_userptr_check_pfns(userptr, vma, start,
+							  next);
+			if (r)
+				break;
+		} else {
+			pr_debug("vma not found for addr: %llx\n", addr);
+			r = -EFAULT;
+			break;
+		}
+
+		addr = next;
+	}
+
+	return r;
+}
+
+static void
+virtio_gpu_update_or_remove_userptr(struct virtio_gpu_object_userptr *userptr,
+				    unsigned long start, unsigned long last)
+{
+	if ((userptr->userptr_start) >= start &&
+	    (userptr->userptr_last) <= last) {
+		if (atomic_xchg(&userptr->in_release, 1) == 0) {
+			virtio_gpu_userptr_add_list_work(userptr,
+							 USERPTR_OP_UNMAP);
+		}
+	} else {
+		pr_debug(
+			"mmu notifier: [%lx-%lx]-%lx userptr: [%llx-%llx]-%llx not match need update.\n",
+			start, last, last - start + 1UL, userptr->userptr_start,
+			userptr->userptr_last,
+			userptr->userptr_last - userptr->userptr_start + 1UL);
+		virtio_gpu_userptr_update_split(userptr, start, last);
+		virtio_gpu_userptr_add_list_work(userptr, USERPTR_OP_UPDATE);
+	}
+}
+
+static void virtio_gpu_userptr_evict(struct virtio_gpu_object_userptr *userptr)
+{
+	if (!userptr->notifier_start || !userptr->notifier_last) {
+		pr_err("userptr: [%llx-%llx] not have notifier range\n",
+		       userptr->userptr_start, userptr->userptr_last);
+		return;
+	}
+
+	if (userptr->notifier_start < userptr->userptr_start ||
+	    userptr->notifier_last > userptr->userptr_last) {
+		pr_err("invalid evict param, userptr: [%llx-%llx] notifier: [%llx-%llx] out of range\n",
+		       userptr->userptr_start, userptr->userptr_last,
+		       userptr->notifier_start, userptr->notifier_last);
+		return;
+	}
+
+	if (virtio_gpu_userptr_check_range(userptr, userptr->notifier_start,
+					   userptr->notifier_last)) {
+		pr_debug("userptr: [%llx-%llx], resid: %d check range failed\n",
+			 userptr->userptr_start, userptr->userptr_last,
+			 userptr->base.hw_res_handle);
+		/* add to work list or process here directly, add to work list here */
+		virtio_gpu_update_or_remove_userptr(
+			userptr, userptr->notifier_start,
+			userptr->notifier_last + (1UL << PAGE_SHIFT) - 1UL);
+	}
+
+	userptr->notifier_start = 0;
+	userptr->notifier_last = 0;
+}
+
+static void
+virtio_gpu_userptr_handle_list_work(struct virtio_gpu_object_userptr *userptr)
+{
+	switch (userptr->op) {
+	case USERPTR_OP_NULL:
+		break;
+	case USERPTR_OP_UNMAP:
+		virtio_gpu_userptr_unmap(userptr);
+		break;
+	case USERPTR_OP_UPDATE:
+		virtio_gpu_userptr_update_notifier_and_interval_tree(userptr);
+		break;
+	case USERPTR_OP_EVICT:
+		virtio_gpu_userptr_evict(userptr);
+		break;
+	default:
+		break;
+	}
+}
+
+static void virtio_gpu_userptr_invalidate_work(struct work_struct *work)
+{
+	struct virtio_gpu_fpriv *vfpriv;
+	struct virtio_gpu_object_userptr *userptr;
+	struct mm_struct *mm;
+
+	vfpriv = container_of(work, struct virtio_gpu_fpriv,
+			      userptr_invalidate_work);
+
+	spin_lock(&vfpriv->userptr_invalidate_list_lock);
+	while (!list_empty(&vfpriv->userptr_invalidate_list)) {
+		userptr = list_first_entry(&vfpriv->userptr_invalidate_list,
+					   struct virtio_gpu_object_userptr,
+					   work_list);
+		spin_unlock(&vfpriv->userptr_invalidate_list_lock);
+
+		mm = userptr->mm;
+
+		mmap_write_lock(mm);
+
+		/* Remove from userptr_invalidate_list_lock must inside mmap write lock, cause:
+		 * after remove from list, the work_item.op may be changed by other thread
+		 * like MMU notifier invalidate callback, and maybe add the userptr to work
+		 * list again.
+		 * What will cause use after free or double free bug.
+		 * So need use mmap_write_lock to prevent the invalidate callback triggering then
+		 * remove the from work list to snsure one work item only be handled once.
+		 */
+		spin_lock(&vfpriv->userptr_invalidate_list_lock);
+		list_del_init(&userptr->work_list);
+		spin_unlock(&vfpriv->userptr_invalidate_list_lock);
+
+		mutex_lock(&vfpriv->userptrs_tree_lock);
+
+		virtio_gpu_userptr_handle_list_work(userptr);
+
+		mutex_unlock(&vfpriv->userptrs_tree_lock);
+		mmap_write_unlock(mm);
+
+		spin_lock(&vfpriv->userptr_invalidate_list_lock);
+	}
+	spin_unlock(&vfpriv->userptr_invalidate_list_lock);
+}
+
+void virtio_gpu_userptr_list_work_init(struct virtio_gpu_fpriv *vfpriv)
+{
+	INIT_WORK(&vfpriv->userptr_invalidate_work,
+		  virtio_gpu_userptr_invalidate_work);
+	INIT_LIST_HEAD(&vfpriv->userptr_invalidate_list);
+	spin_lock_init(&vfpriv->userptr_invalidate_list_lock);
+}
+
+static void
+virtio_gpu_userptr_schedule_list_work(struct virtio_gpu_fpriv *vfpriv)
+{
+	spin_lock(&vfpriv->userptr_invalidate_list_lock);
+	if (!list_empty(&vfpriv->userptr_invalidate_list))
+		schedule_work(&vfpriv->userptr_invalidate_work);
+	spin_unlock(&vfpriv->userptr_invalidate_list_lock);
+}
+
+static void virtio_gpu_object_userptr_remove_within_range(
+	struct virtio_gpu_fpriv *vfpriv, u_int64_t start, u_int64_t last,
+	bool check_start, const char *from)
+{
+	struct interval_tree_node *node;
+	struct virtio_gpu_object_userptr *userptr = NULL;
+	uint64_t remove_userptr_size = last - start + 1UL;
+	uint64_t userptr_size;
+
+	mutex_lock(&vfpriv->userptrs_tree_lock);
+
+	node = interval_tree_iter_first(&vfpriv->userptrs_tree, start, last);
+
+	while (node) {
+		struct interval_tree_node *next;
+
+		userptr = container_of(node, struct virtio_gpu_object_userptr,
+				       it_node);
+
+		userptr_size =
+			userptr->userptr_last - userptr->userptr_start + 1UL;
+		if (userptr->userptr_start >= start &&
+		    userptr->userptr_last < last) {
+			if ((!check_start) ||
+			    (check_start && userptr->userptr_start == start)) {
+				if (atomic_xchg(&userptr->in_release, 1) == 0 &&
+				    !userptr->op) {
+					userptr->mm = current->mm;
+					virtio_gpu_userptr_add_list_work(
+						userptr, USERPTR_OP_UNMAP);
+				}
+			}
+		}
+
+		next = interval_tree_iter_next(node, start, last);
+		node = next;
+	}
+	mutex_unlock(&vfpriv->userptrs_tree_lock);
+
+	virtio_gpu_userptr_schedule_list_work(userptr->file->driver_priv);
+}
+
+static bool
+virtio_gpu_userptr_invalidate(struct mmu_interval_notifier *mn,
+			      const struct mmu_notifier_range *range,
+			      unsigned long cur_seq)
+{
+	struct virtio_gpu_object_userptr *userptr;
+	struct virtio_gpu_fpriv *vfpriv;
+	unsigned long start;
+	unsigned long last;
+
+	if (range->event == MMU_NOTIFY_RELEASE)
+		return true;
+	if (!mmget_not_zero(mn->mm))
+		return true;
+
+	start = mn->interval_tree.start;
+	last = mn->interval_tree.last;
+	start = (max(start, range->start) >> PAGE_SHIFT) << PAGE_SHIFT;
+	last = (min(last, range->end - 1UL) >> PAGE_SHIFT) << PAGE_SHIFT;
+
+	userptr = container_of(mn, struct virtio_gpu_object_userptr, notifier);
+	userptr->mm = mn->mm;
+	vfpriv = userptr->file->driver_priv;
+
+	mutex_lock(&userptr->lock);
+	mmu_interval_set_seq(mn, cur_seq);
+
+	pr_debug(
+		"userptr: [%llx-%llx]-%llx notifier: [%lx-%lx]-%lx check: [%lx-%lx]-%lx resid: %d event: %d\n",
+		userptr->userptr_start, userptr->userptr_last,
+		userptr->userptr_last - userptr->userptr_start + 1UL,
+		range->start, range->end - 1UL, range->end - range->start,
+		start, last, last - start + (1UL << PAGE_SHIFT),
+		userptr->base.hw_res_handle, range->event);
+
+	if (userptr->op == USERPTR_OP_UNMAP) {
+		pr_debug(
+			"userptr: [%llx-%llx] resid: %d already in unmap op: %d\n",
+			userptr->userptr_start, userptr->userptr_last,
+			userptr->base.hw_res_handle, userptr->op);
+	} else {
+		switch (range->event) {
+		case MMU_NOTIFY_UNMAP:
+			virtio_gpu_update_or_remove_userptr(
+				userptr, start,
+				last + (1UL << PAGE_SHIFT) - 1UL);
+			break;
+		default:
+			userptr->notifier_start = start;
+			userptr->notifier_last = last;
+			virtio_gpu_userptr_add_list_work(userptr,
+							 USERPTR_OP_EVICT);
+			break;
+		}
+	}
+
+	virtio_gpu_userptr_schedule_list_work(userptr->file->driver_priv);
+
+	mutex_unlock(&userptr->lock);
+	mmput(mn->mm);
+	return true;
+}
+
+static void
+virtio_gpu_userptr_lock_and_flush_work(struct virtio_gpu_fpriv *vfpriv,
+				       struct mm_struct *mm)
+{
+retry_flush_work:
+	flush_work(&vfpriv->userptr_invalidate_work);
+
+	if (list_empty(&vfpriv->userptr_invalidate_list))
+		return;
+
+	goto retry_flush_work;
+}
+
+void virtio_gpu_userptr_set_handle(struct virtio_gpu_object *qobj,
+				   uint32_t handle)
+{
+	struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(qobj);
+
+	userptr->bo_handle = handle;
+	virtio_gpu_object_userptr_remove_within_range(
+		userptr->file->driver_priv, userptr->userptr_start,
+		userptr->userptr_last, false, __func__);
+	virtio_gpu_userptr_add_notifier(userptr, userptr->userptr_start,
+					userptr->npages << PAGE_SHIFT);
+}
+
+static int virtio_gpu_userptr_init(struct drm_device *dev,
+				   struct drm_file *file,
+				   struct drm_gem_object *obj,
+				   struct virtio_gpu_object_params *params,
+				   unsigned long **p_pfns, uint32_t *p_npfns)
+{
+	struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
+	struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(bo);
+	unsigned long page_offset;
+	unsigned long aligned_size;
+	struct page **pages;
+	unsigned int pinned = 0;
+	uint64_t aligned_addr;
+	int ret;
+
+	page_offset = (uint64_t)params->blob_userptr & (PAGE_SIZE - 1UL);
+	aligned_addr = params->blob_userptr - page_offset;
+	aligned_size = roundup(page_offset + params->size, PAGE_SIZE);
+
+	pr_debug(
+		"create userptr addr: %llx size: %lx, aligned: [%llx-%llx]-%lx\n",
+		params->blob_userptr, params->size, aligned_addr,
+		aligned_addr + aligned_size - 1UL, aligned_size);
+
+	params->size = aligned_size;
+
+	drm_gem_private_object_init(dev, obj, aligned_size);
+
+	*p_npfns = aligned_size / PAGE_SIZE;
+	*p_pfns = vmalloc(*p_npfns * sizeof(unsigned long));
+	if (!(*p_pfns)) {
+		pr_err("failed to allocate userptr pfns\n");
+		return -ENOMEM;
+	}
+
+	pages = vmalloc(*p_npfns * sizeof(struct page *));
+	if (!pages)
+		return -ENOMEM;
+
+	userptr->userptr_inital_start = aligned_addr;
+	userptr->userptr_start = aligned_addr;
+	userptr->userptr_last = userptr->userptr_start + aligned_size - 1UL;
+
+	do {
+		unsigned int num_pages = *p_npfns - pinned;
+		uint64_t ptr = userptr->userptr_start + pinned * PAGE_SIZE;
+		struct page **pinned_pages = pages + pinned;
+
+		ret = pin_user_pages_fast(
+			ptr, num_pages, FOLL_WRITE | FOLL_FORCE, pinned_pages);
+
+		if (ret < 0) {
+			pr_err("pin memory failed, addr: 0x%llx\n",
+			       userptr->userptr_start);
+			if (pinned && pages)
+				unpin_user_pages(pages, pinned);
+			userptr->userptr_start = 0;
+			vfree(pages);
+			vfree(*p_pfns);
+			return -ENOMEM;
+		}
+
+		pinned += ret;
+
+	} while (pinned < *p_npfns);
+
+	userptr->pages = pages;
+	userptr->npages = *p_npfns;
+	bo->base.base.size = aligned_size;
+
+	for (int i = 0; i < (*p_npfns); i++)
+		(*p_pfns)[i] = page_to_pfn(pages[i]);
+
+	atomic_set(&userptr->in_release, 0);
+	INIT_LIST_HEAD(&userptr->work_list);
+	mutex_init(&userptr->lock);
+	userptr->vgdev = dev->dev_private;
+	userptr->file = file;
+
+	return 0;
+}
+
+int virtio_gpu_userptr_create(struct virtio_gpu_device *vgdev,
+			      struct drm_file *file,
+			      struct virtio_gpu_object_params *params,
+			      struct virtio_gpu_object **bo_ptr)
+{
+	struct mm_struct *mm = current->mm;
+	struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
+	struct drm_gem_object *obj;
+	struct virtio_gpu_object_userptr *userptr;
+	int ret;
+	unsigned long *pfns;
+	uint32_t npfns;
+
+	virtio_gpu_userptr_lock_and_flush_work(vfpriv, mm);
+
+	mutex_lock(&vfpriv->userptrs_tree_lock);
+	userptr = virtio_gpu_userptr_from_addr_range(
+		vfpriv, params->blob_userptr,
+		params->blob_userptr + params->size - 1UL);
+	if (userptr) {
+		*bo_ptr = &userptr->base;
+		mutex_unlock(&vfpriv->userptrs_tree_lock);
+		return USERPTR_EXISTS;
+	}
+
+	userptr = kzalloc(sizeof(*userptr), GFP_KERNEL);
+	if (!userptr)
+		return -ENOMEM;
+
+	obj = &userptr->base.base.base;
+	obj->funcs = &virtio_gpu_userptr_funcs;
+
+	ret = virtio_gpu_userptr_init(vgdev->ddev, file, obj, params, &pfns,
+				      &npfns);
+	if (ret)
+		goto failed_free;
+
+	ret = virtio_gpu_resource_id_get(vgdev, &userptr->base.hw_res_handle);
+	if (ret)
+		goto failed_free;
+
+	virtio_gpu_userptr_add_interval_tree(vfpriv, userptr);
+	/* virtio_gpu_userptr_dump(vfpriv); */
+
+	mutex_unlock(&vfpriv->userptrs_tree_lock);
+
+	virtio_gpu_cmd_resource_create_userptr(vgdev, &userptr->base, params,
+					       pfns, npfns);
+
+	*bo_ptr = &userptr->base;
+	return 0;
+
+failed_free:
+	mutex_unlock(&vfpriv->userptrs_tree_lock);
+	kfree(userptr);
+	return ret;
+}
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 29d462b69bad..2699b85829f4 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -1270,6 +1270,35 @@  virtio_gpu_cmd_resource_create_blob(struct virtio_gpu_device *vgdev,
 	bo->created = true;
 }
 
+void
+virtio_gpu_cmd_resource_create_userptr(struct virtio_gpu_device *vgdev,
+				    struct virtio_gpu_object *bo,
+				    struct virtio_gpu_object_params *params,
+				    unsigned long *pfns,
+				    uint32_t npfns)
+{
+	struct virtio_gpu_resource_create_blob *cmd_p;
+	struct virtio_gpu_vbuffer *vbuf;
+
+	cmd_p = virtio_gpu_alloc_cmd(vgdev, &vbuf, sizeof(*cmd_p));
+	memset(cmd_p, 0, sizeof(*cmd_p));
+
+	cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_CREATE_BLOB);
+	cmd_p->hdr.ctx_id = cpu_to_le32(params->ctx_id);
+	cmd_p->resource_id = cpu_to_le32(bo->hw_res_handle);
+	cmd_p->blob_mem = cpu_to_le32(params->blob_mem);
+	cmd_p->blob_flags = cpu_to_le32(params->blob_flags);
+	cmd_p->blob_id = cpu_to_le64(params->blob_id);
+	cmd_p->size = cpu_to_le64(params->size);
+	cmd_p->nr_entries = cpu_to_le32(npfns);
+
+	vbuf->data_buf = pfns;
+	vbuf->data_size = sizeof(*pfns) * npfns;
+
+	virtio_gpu_queue_ctrl_buffer(vgdev, vbuf);
+	bo->created = true;
+}
+
 void virtio_gpu_cmd_set_scanout_blob(struct virtio_gpu_device *vgdev,
 				     uint32_t scanout_id,
 				     struct virtio_gpu_object *bo,