diff mbox series

[v2,09/10] vfio: Support IO page table replacement

Message ID 121b90a852cb53f3425ed0660173f12d15ed0137.1675802050.git.nicolinc@nvidia.com
State New
Headers
Series Add IO page table replacement support |

Commit Message

Nicolin Chen Feb. 7, 2023, 9:18 p.m. UTC 
  Remove the vdev->iommufd_attached check, since the kernel can internally
handle a replacement of the IO page table now.

Also update the VFIO_DEVICE_ATTACH_IOMMUFD_PT kdoc in the uAPI header.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/vfio/iommufd.c    | 3 ---
 include/uapi/linux/vfio.h | 6 ++++++
 2 files changed, 6 insertions(+), 3 deletions(-)

Comments

Tian, Kevin Feb. 9, 2023, 4:06 a.m. UTC | #1 
> From: Nicolin Chen <nicolinc@nvidia.com>
> Sent: Wednesday, February 8, 2023 5:18 AM
> 
> Remove the vdev->iommufd_attached check, since the kernel can internally
> handle a replacement of the IO page table now.
> 
> Also update the VFIO_DEVICE_ATTACH_IOMMUFD_PT kdoc in the uAPI
> header.
> 
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
diff mbox series

Patch

diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
index dc9feab73db7..8b719d9424b8 100644
--- a/drivers/vfio/iommufd.c
+++ b/drivers/vfio/iommufd.c
@@ -97,9 +97,6 @@  int vfio_iommufd_physical_attach_ioas(struct vfio_device *vdev, u32 *pt_id)
 	if (!vdev->iommufd_device)
 		return -EINVAL;
 
-	if (vdev->iommufd_attached)
-		return -EBUSY;
-
 	rc = iommufd_device_attach(vdev->iommufd_device, pt_id);
 	if (rc)
 		return rc;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index c86cfe442884..69f3ceb18d7d 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -236,6 +236,12 @@  struct vfio_device_bind_iommufd {
  *
  * Undo by VFIO_DEVICE_DETACH_IOMMUFD_PT or device fd close.
  *
+ * If a vfio device is currently attached to a valid hw_pagetable, without doing
+ * a VFIO_DEVICE_DETACH_IOMMUFD_PT, a second VFIO_DEVICE_ATTACH_IOMMUFD_PT ioctl
+ * passing in another hw_pagetable (hwpt) id is allowed. This action, also known
+ * as a hw_pagetable replacement, will replace the device's currently attached
+ * hw_pagetable with a new hw_pagetable corresponding to the given pt_id.
+ *
  * @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