It is to solve the lifecycle issue that vdevice may outlive idevice. It
is a prerequisite for TIO, to ensure extra secure configurations (e.g.
TSM Bind/Unbind) against vdevice could be rolled back on idevice unbind,
so that VFIO could still work on the physical device without surprise.

Changelog:
v5:
 - Further rebase to iommufd for-next 601b1d0d9395
 - Keep the xa_empty() check in iommufd_fops_release(), update comments
 - Move the *idev next to *viommu for struct iommufd_vdevice
 - Update the description about IOMMUFD_CMD_VDEVICE_ALLOC for lifecycle
 - Remove Baolu's tag for patch 4 because of big changes since v3
 - Add changelog about idev->destroying
 - Adjust line wrappings for tools/testing/selftests/iommu/iommufd.c
 - Clarify that no testing for tombstoned ID repurposing.
 - Add review tags.

v4: https://lore.kernel.org/linux-iommu/20250709040234.1773573-1-yilun.xu@linux.intel.com/
 - Rebase to iommufd for-next.
 - A new patch to roll back iommufd_object_alloc_ucmd() for vdevice.
 - Fix the mistake trying to xa_destroy ictx->groups on
   iommufd_fops_release().
 - Move 'empty' flag inside destroy loop for iommufd_fops_release().
 - Refactor vdev/idev destroy syncing.
   - Drop the iommufd_vdevice_abort() reentrant idea.
   - A new patch that adds pre_destroy() op.
   - Hold short term reference during the whole vdevice's lifecycle.
   - Wait on short term reference on idev's pre_destroy().
   - Add a 'destroying' flag for idev to prevent new reference after
     pre_destroy().
 - Rephrase/fix some comments.
 - Add review tags.

v3: https://lore.kernel.org/linux-iommu/20250627033809.1730752-1-yilun.xu@linux.intel.com/
 - No bother clean each tombstone in iommufd_fops_release().
 - Drop vdev->ictx initialization fix patch.
 - Optimize control flow in iommufd_device_remove_vdev().
 - Make iommufd_vdevice_abort() reentrant.
 - Call iommufd_vdevice_abort() directly instead of waiting for it.
 - Rephrase/fix some comments.
 - A new patch to remove vdev->dev.
 - A new patch to explicitly skip existing viommu tests for no_iommu.
 - Also skip vdevice tombstone test for no_iommu.
 - Allow me to add SoB from Aneesh.

v2: https://lore.kernel.org/linux-iommu/20250623094946.1714996-1-yilun.xu@linux.intel.com/

v1/rfc: https://lore.kernel.org/linux-iommu/20250610065146.1321816-1-aneesh.kumar@kernel.org/

The series is based on iommufd for-next


Xu Yilun (8):
  iommufd/viommu: Roll back to use iommufd_object_alloc() for vdevice
  iommufd: Add iommufd_object_tombstone_user() helper
  iommufd: Add a pre_destroy() op for objects
  iommufd: Destroy vdevice on idevice destroy
  iommufd/vdevice: Remove struct device reference from struct vdevice
  iommufd/selftest: Explicitly skip tests for inapplicable variant
  iommufd/selftest: Add coverage for vdevice tombstone
  iommufd: Rename some shortterm-related identifiers

 .../iommu/arm/arm-smmu-v3/tegra241-cmdqv.c    |   2 +-
 drivers/iommu/iommufd/device.c                |  51 +++
 drivers/iommu/iommufd/driver.c                |   4 +-
 drivers/iommu/iommufd/iommufd_private.h       |  49 ++-
 drivers/iommu/iommufd/main.c                  |  69 +++-
 drivers/iommu/iommufd/viommu.c                |  69 +++-
 include/linux/iommufd.h                       |  10 +-
 include/uapi/linux/iommufd.h                  |   5 +
 tools/testing/selftests/iommu/iommufd.c       | 379 +++++++++---------
 9 files changed, 407 insertions(+), 231 deletions(-)


base-commit: 601b1d0d9395c711383452bd0d47037afbbb4bcf
-- 
2.25.1

On Tue, Jul 15, 2025 at 02:32:37PM +0800, Xu Yilun wrote:
> It is to solve the lifecycle issue that vdevice may outlive idevice. It
> is a prerequisite for TIO, to ensure extra secure configurations (e.g.
> TSM Bind/Unbind) against vdevice could be rolled back on idevice unbind,
> so that VFIO could still work on the physical device without surprise.
> 
> Changelog:
> v5:
>  - Further rebase to iommufd for-next 601b1d0d9395
>  - Keep the xa_empty() check in iommufd_fops_release(), update comments
>  - Move the *idev next to *viommu for struct iommufd_vdevice
>  - Update the description about IOMMUFD_CMD_VDEVICE_ALLOC for lifecycle
>  - Remove Baolu's tag for patch 4 because of big changes since v3
>  - Add changelog about idev->destroying
>  - Adjust line wrappings for tools/testing/selftests/iommu/iommufd.c
>  - Clarify that no testing for tombstoned ID repurposing.
>  - Add review tags.

With the patch that I attached in my reply to PATCH-5, sanity works
fine per iommufd's selftest and by testing tegra241-cmdqv in a VM.

So, upon fixing the build break in PATCH-5 (maybe for a v6),

Tested-by: Nicolin Chen <nicolinc@nvidia.com>