Re: [PATCH 1/1] iommu/vt-d: Correctly calculate sagaw value of IOMMU

[Baolu Lu]

On 2022/8/17 10:35, Lu Baolu wrote:
> The Intel IOMMU driver possibly selects between the first-level and the
> second-level translation tables for DMA address translation. However,
> the levels of page-table walks for the 4KB base page size are calculated
> from the SAGAW field of the capability register, which is only valid for
> the second-level page table. This causes the IOMMU driver to stop working
> if the hardware (or the emulated IOMMU) advertises only first-level
> translation capability and reports the SAGAW field as 0.
>
> This solves the above problem by considering both the first level and the
> second level when calculating the supported page table levels.
>
> Fixes: b802d070a52a1 ("iommu/vt-d: Use iova over first level")
> Cc:stable@xxxxxxxxxxxxxxx
> Signed-off-by: Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>

This patch has been queued:

https://lore.kernel.org/linux-iommu/20220823061557.1631056-1-baolu.lu@xxxxxxxxxxxxxxx/

Best regards,
baolu