iommu/arm-smmu-v3: Add a missing dma_wmb() for hitless STE update

Browse source

When writing a new (previously invalid) valid IOPTE to a page table, then
installing the page table into an STE hitlesslessly (e.g. in S2TTB field),
there is a window before an STE invalidation, where the page-table may be
accessed by SMMU but the new IOPTE is still siting in the CPU cache.

This could occur when we allocate an iommu_domain and immediately install
it hitlessly, while there would be no dma_wmb() for the page table memory
prior to the earliest point of HW reading the STE.

Fix it by adding a dma_wmb() prior to updating the STE.

Fixes: 56e1a4cc25 ("iommu/arm-smmu-v3: Add unit tests for arm_smmu_write_entry")
Cc: stable@vger.kernel.org
Reported-by: Will Deacon <will@kernel.org>
Closes: https://lore.kernel.org/linux-iommu/aXdlnLLFUBwjT0V5@willie-the-truck/
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Will Deacon <will@kernel.org>

...

This commit is contained in:

Nicolin Chen 2026-03-17 00:59:16 -07:00 • committed by Will Deacon

parent f338e77383

commit 6fabce53f6

1 changed files with 7 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

7

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c

View file