Re: [PATCH v5 05/18] iommu: Pass in reset result to pci_dev_reset_iommu_done()

[sashiko-bot@kernel.org]

> IOMMU drivers handle ATC cache maintenance. They may encounter ATC-related
> errors (e.g., ATC invalidation timeout), indicating that the ATC cache may
> have stale entries that can corrupt the memory. In this case, IOMMU driver
> has no choice but to block the device's ATS function and wait for a device
> recovery.
> 
> The pci_dev_reset_iommu_done() called at the end of a reset function could
> serve as a reliable signal to the IOMMU subsystem that the physical device
> cache is completely clean. However, the function is called unconditionally
> even if the reset operation had actually failed, which would re-attach the
> faulty device back to a normal translation domain. And this will leave the
> system highly exposed, creating vulnerabilities for data corruption:
>     IOMMU blocks RID/ATS
>     pci_reset_function():
>         pci_dev_reset_iommu_prepare(); // Block RID/ATS
> [ ... ]
> This introduces a new situation where a blocked device is being unplugged.
> Decrement the group->recovery_cnt accordingly.
> 
> Suggested-by: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/cover.1783044582.git.nicolinc@nvidia.com?part=5