diff mbox series

[v12,19/24] vfio: Add VFIO_DEVICE_[AT|DE]TACH_IOMMUFD_PT

Message ID 20230602121653.80017-20-yi.l.liu@intel.com (mailing list archive)
State New, archived
Headers show
Series Add vfio_device cdev for iommufd support | expand

Commit Message

Yi Liu June 2, 2023, 12:16 p.m. UTC
This adds ioctl for userspace to attach device cdev fd to and detach
from IOAS/hw_pagetable managed by iommufd.

    VFIO_DEVICE_ATTACH_IOMMUFD_PT: attach vfio device to IOAS, hw_pagetable
				   managed by iommufd. Attach can be
				   undo by VFIO_DEVICE_DETACH_IOMMUFD_PT
				   or device fd close.
    VFIO_DEVICE_DETACH_IOMMUFD_PT: detach vfio device from the current attached
				   IOAS or hw_pagetable managed by iommufd.

noiommu devices do not support [AT|DE]TACH, if user invokes the two ioctls
on such devices, shall fail.

Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: Terrence Xu <terrence.xu@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
 drivers/vfio/device_cdev.c | 66 ++++++++++++++++++++++++++++++++++++++
 drivers/vfio/vfio.h        | 16 +++++++++
 drivers/vfio/vfio_main.c   |  8 +++++
 include/uapi/linux/vfio.h  | 42 ++++++++++++++++++++++++
 4 files changed, 132 insertions(+)

Comments

Jason Gunthorpe June 23, 2023, 4:21 p.m. UTC | #1
On Fri, Jun 02, 2023 at 05:16:48AM -0700, Yi Liu wrote:
> This adds ioctl for userspace to attach device cdev fd to and detach
> from IOAS/hw_pagetable managed by iommufd.
> 
>     VFIO_DEVICE_ATTACH_IOMMUFD_PT: attach vfio device to IOAS, hw_pagetable
> 				   managed by iommufd. Attach can be
> 				   undo by VFIO_DEVICE_DETACH_IOMMUFD_PT
> 				   or device fd close.
>     VFIO_DEVICE_DETACH_IOMMUFD_PT: detach vfio device from the current attached
> 				   IOAS or hw_pagetable managed by iommufd.
> 
> noiommu devices do not support [AT|DE]TACH, if user invokes the two ioctls
> on such devices, shall fail.

Stale comment

> Tested-by: Yanting Jiang <yanting.jiang@intel.com>
> Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> Tested-by: Terrence Xu <terrence.xu@intel.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
>  drivers/vfio/device_cdev.c | 66 ++++++++++++++++++++++++++++++++++++++
>  drivers/vfio/vfio.h        | 16 +++++++++
>  drivers/vfio/vfio_main.c   |  8 +++++
>  include/uapi/linux/vfio.h  | 42 ++++++++++++++++++++++++
>  4 files changed, 132 insertions(+)
> 
> diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c
> index a4498ddbe774..6e1d499ee160 100644
> --- a/drivers/vfio/device_cdev.c
> +++ b/drivers/vfio/device_cdev.c
> @@ -167,6 +167,72 @@ long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df,
>  	return ret;
>  }
>  
> +int vfio_df_ioctl_attach_pt(struct vfio_device_file *df,
> +			    struct vfio_device_attach_iommufd_pt __user *arg)
> +{
> +	struct vfio_device *device = df->device;
> +	struct vfio_device_attach_iommufd_pt attach;
> +	unsigned long minsz;
> +	int ret;
> +
> +	minsz = offsetofend(struct vfio_device_attach_iommufd_pt, pt_id);
> +
> +	if (copy_from_user(&attach, arg, minsz))
> +		return -EFAULT;
> +
> +	if (attach.argsz < minsz || attach.flags)
> +		return -EINVAL;
> +
> +	/* ATTACH only allowed for cdev fds */
> +	if (df->group)
> +		return -EINVAL;

I feel like vfio_device_fops_unl_ioctl() should do these group tests
for the whole lot

@@ -1187,19 +1187,24 @@ static long vfio_device_fops_unl_ioctl(struct file *filep,
        if (ret)
                return ret;
 
+       /* cdev only ioctls */
+       if (IS_ENABLED(CONFIG_VFIO_DEVICE_CDEV) && !df->group) {
+               switch (cmd) {
+               case VFIO_DEVICE_ATTACH_IOMMUFD_PT:
+                       ret = vfio_df_ioctl_attach_pt(df, (void __user *)arg);
+                       goto out;
+
+               case VFIO_DEVICE_DETACH_IOMMUFD_PT:
+                       ret = vfio_df_ioctl_detach_pt(df, (void __user *)arg);
+                       goto out;
+               }
+       }
+
        switch (cmd) {
        case VFIO_DEVICE_FEATURE:
                ret = vfio_ioctl_device_feature(device, (void __user *)arg);
                break;
 
-       case VFIO_DEVICE_ATTACH_IOMMUFD_PT:
-               ret = vfio_df_ioctl_attach_pt(df, (void __user *)arg);
-               break;
-
-       case VFIO_DEVICE_DETACH_IOMMUFD_PT:
-               ret = vfio_df_ioctl_detach_pt(df, (void __user *)arg);
-               break;
-
        default:
                if (unlikely(!device->ops->ioctl))
                        ret = -EINVAL;

And also make a local var for void __user * to avoid the repeated
casts.

Also this construction avoids the stub static inlines since the
IS_ENABLED will compile out the call. Just use a normal function
prototype outside any ifdef.

> +
> +	mutex_lock(&device->dev_set->lock);
> +	ret = device->ops->attach_ioas(device, &attach.pt_id);
> +	if (ret)
> +		goto out_unlock;
> +
> +	ret = copy_to_user(&arg->pt_id, &attach.pt_id,
> +			   sizeof(attach.pt_id)) ? -EFAULT : 0;
> +	if (ret)
> +		goto out_detach;

Don't use the ?:

if (copy_to_user()..) {
    ret = -EFAULT;
    goto out_detach;
}

Jason
diff mbox series

Patch

diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c
index a4498ddbe774..6e1d499ee160 100644
--- a/drivers/vfio/device_cdev.c
+++ b/drivers/vfio/device_cdev.c
@@ -167,6 +167,72 @@  long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df,
 	return ret;
 }
 
+int vfio_df_ioctl_attach_pt(struct vfio_device_file *df,
+			    struct vfio_device_attach_iommufd_pt __user *arg)
+{
+	struct vfio_device *device = df->device;
+	struct vfio_device_attach_iommufd_pt attach;
+	unsigned long minsz;
+	int ret;
+
+	minsz = offsetofend(struct vfio_device_attach_iommufd_pt, pt_id);
+
+	if (copy_from_user(&attach, arg, minsz))
+		return -EFAULT;
+
+	if (attach.argsz < minsz || attach.flags)
+		return -EINVAL;
+
+	/* ATTACH only allowed for cdev fds */
+	if (df->group)
+		return -EINVAL;
+
+	mutex_lock(&device->dev_set->lock);
+	ret = device->ops->attach_ioas(device, &attach.pt_id);
+	if (ret)
+		goto out_unlock;
+
+	ret = copy_to_user(&arg->pt_id, &attach.pt_id,
+			   sizeof(attach.pt_id)) ? -EFAULT : 0;
+	if (ret)
+		goto out_detach;
+	mutex_unlock(&device->dev_set->lock);
+
+	return 0;
+
+out_detach:
+	device->ops->detach_ioas(device);
+out_unlock:
+	mutex_unlock(&device->dev_set->lock);
+	return ret;
+}
+
+int vfio_df_ioctl_detach_pt(struct vfio_device_file *df,
+			    struct vfio_device_detach_iommufd_pt __user *arg)
+{
+	struct vfio_device *device = df->device;
+	struct vfio_device_detach_iommufd_pt detach;
+	unsigned long minsz;
+
+	minsz = offsetofend(struct vfio_device_detach_iommufd_pt, flags);
+
+	if (copy_from_user(&detach, arg, minsz))
+		return -EFAULT;
+
+	if (detach.argsz < minsz || detach.flags)
+		return -EINVAL;
+
+	/* DETACH only allowed for cdev fds */
+	if (df->group)
+		return -EINVAL;
+
+	mutex_lock(&device->dev_set->lock);
+	device->ops->detach_ioas(device);
+	mutex_unlock(&device->dev_set->lock);
+
+	return 0;
+}
+
 static char *vfio_device_devnode(const struct device *dev, umode_t *mode)
 {
 	return kasprintf(GFP_KERNEL, "vfio/devices/%s", dev_name(dev));
diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
index 42de40d2cd4d..5835c74e97ce 100644
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -290,6 +290,10 @@  int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep);
 void vfio_df_cdev_close(struct vfio_device_file *df);
 long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df,
 				struct vfio_device_bind_iommufd __user *arg);
+int vfio_df_ioctl_attach_pt(struct vfio_device_file *df,
+			    struct vfio_device_attach_iommufd_pt __user *arg);
+int vfio_df_ioctl_detach_pt(struct vfio_device_file *df,
+			    struct vfio_device_detach_iommufd_pt __user *arg);
 int vfio_cdev_init(struct class *device_class);
 void vfio_cdev_cleanup(void);
 #else
@@ -323,6 +327,18 @@  static inline long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df,
 	return -EOPNOTSUPP;
 }
 
+static inline int vfio_df_ioctl_attach_pt(struct vfio_device_file *df,
+					  struct vfio_device_attach_iommufd_pt __user *arg)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int vfio_df_ioctl_detach_pt(struct vfio_device_file *df,
+					  struct vfio_device_detach_iommufd_pt __user *arg)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline int vfio_cdev_init(struct class *device_class)
 {
 	return 0;
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 9ba4d420eda2..6d8f9b0f3637 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -1163,6 +1163,14 @@  static long vfio_device_fops_unl_ioctl(struct file *filep,
 		ret = vfio_ioctl_device_feature(device, (void __user *)arg);
 		break;
 
+	case VFIO_DEVICE_ATTACH_IOMMUFD_PT:
+		ret = vfio_df_ioctl_attach_pt(df, (void __user *)arg);
+		break;
+
+	case VFIO_DEVICE_DETACH_IOMMUFD_PT:
+		ret = vfio_df_ioctl_detach_pt(df, (void __user *)arg);
+		break;
+
 	default:
 		if (unlikely(!device->ops->ioctl))
 			ret = -EINVAL;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 7296012b7f36..355deb852e78 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -221,6 +221,48 @@  struct vfio_device_bind_iommufd {
 
 #define VFIO_DEVICE_BIND_IOMMUFD	_IO(VFIO_TYPE, VFIO_BASE + 18)
 
+/*
+ * VFIO_DEVICE_ATTACH_IOMMUFD_PT - _IOW(VFIO_TYPE, VFIO_BASE + 19,
+ *					struct vfio_device_attach_iommufd_pt)
+ * @argsz:	User filled size of this data.
+ * @flags:	Must be 0.
+ * @pt_id:	Input the target id which can represent an ioas or a hwpt
+ *		allocated via iommufd subsystem.
+ *		Output the input ioas id or the attached hwpt id which could
+ *		be the specified hwpt itself or a hwpt automatically created
+ *		for the specified ioas by kernel during the attachment.
+ *
+ * Associate the device with an address space within the bound iommufd.
+ * Undo by VFIO_DEVICE_DETACH_IOMMUFD_PT or device fd close.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+struct vfio_device_attach_iommufd_pt {
+	__u32	argsz;
+	__u32	flags;
+	__u32	pt_id;
+};
+
+#define VFIO_DEVICE_ATTACH_IOMMUFD_PT		_IO(VFIO_TYPE, VFIO_BASE + 19)
+
+/*
+ * VFIO_DEVICE_DETACH_IOMMUFD_PT - _IOW(VFIO_TYPE, VFIO_BASE + 20,
+ *					struct vfio_device_detach_iommufd_pt)
+ * @argsz:	User filled size of this data.
+ * @flags:	Must be 0.
+ *
+ * Remove the association of the device and its current associated address
+ * space.  After it, the device should be in a blocking DMA state.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+struct vfio_device_detach_iommufd_pt {
+	__u32	argsz;
+	__u32	flags;
+};
+
+#define VFIO_DEVICE_DETACH_IOMMUFD_PT		_IO(VFIO_TYPE, VFIO_BASE + 20)
+
 /**
  * VFIO_DEVICE_GET_INFO - _IOR(VFIO_TYPE, VFIO_BASE + 7,
  *						struct vfio_device_info)