[PATCH v2 0/3] iommufd: Fix vDEVICE allocation lifecycle bugs

[Nicolin Chen <nicolinc@nvidia.com>]

Sashiko flagged a few bugs in how IOMMU_VDEVICE_ALLOC creates and validates
a vDEVICE on a vIOMMU:

 - the core publishes a vDEVICE into the vIOMMU xarray before the driver's
   vdevice_init() runs, so a concurrent invalidation can reach one it has
   not yet accepted;
 - the undersized-vdevice_size guard returns holding the igroup mutex,
   deadlocking later vDEVICE operations on that group;
 - the Arm SMMUv3 vIOMMU accepts a device without exactly one Stream ID:
   an out-of-bounds streams[] read for none, stale ATC/IOTLB for several.

Fix each of them properly.

This is on Github:
https://github.com/nicolinc/iommufd/commits/fix_vdevice_sashiko-v2

Changelog
v2
 * Add "Reviewed-by" from Kevin
 * Patch-2: Add "Cc stable"; drop the out_release label by inlining the
   xa_release() call
 * Patch-2: Note that the reserved slot is hidden only via xa_* helpers
 * Patch-3: Return -EOPNOTSUPP instead of -EINVAL
v1
 https://lore.kernel.org/all/cover.1782767110.git.nicolinc@nvidia.com/

Nicolin Chen (3):
  iommufd/viommu: Release the igroup lock on the vdevice_size error path
  iommufd/viommu: Publish a vDEVICE only after vdevice_init() succeeds
  iommu/arm-smmu-v3-iommufd: Require exactly one Stream ID for a vDEVICE

 .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c     | 15 +++++++++++++
 drivers/iommu/iommufd/viommu.c                | 22 ++++++++++++++-----
 2 files changed, 31 insertions(+), 6 deletions(-)

-- 
2.43.0