iommu/amd: Fix illegal cap/mmio access in IOMMU debugfs

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In the current AMD IOMMU debugfs, when multiple processes simultaneously
access the IOMMU mmio/cap registers using the IOMMU debugfs, illegal
access issues can occur in the following execution flow:

1. CPU1: Sets a valid access address using iommu_mmio/capability_write,
and verifies the access address's validity in iommu_mmio/capability_show

2. CPU2: Sets an invalid address using iommu_mmio/capability_write

3. CPU1: accesses the IOMMU mmio/cap registers based on the invalid
address, resulting in an illegal access.

This patch modifies the execution process to first verify the address's
validity and then access it based on the same address, ensuring
correctness and robustness.

Signed-off-by: Guanghui Feng <guanghuifeng@linux.alibaba.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

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This commit is contained in:

Guanghui Feng 2026-03-19 15:37:54 +08:00 • committed by Joerg Roedel

parent e4172c5b53

commit 0e59645683

1 changed files with 19 additions and 23 deletions

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drivers/iommu/amd/debugfs.c

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