[PATCH v1 0/3] iommufd: Fix vDEVICE allocation lifecycle bugs

Nicolin Chen nicolinc at nvidia.com
Mon Jun 29 14:16:23 PDT 2026


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-v1

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

 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 15 +++++++++++++++
 drivers/iommu/iommufd/viommu.c                  | 17 +++++++++++------
 2 files changed, 26 insertions(+), 6 deletions(-)


base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482
-- 
2.43.0




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