Re: [PATCH v2 1/1] iommu/vt-d: Fix kdump kernels boot failure with scalable mode

Baolu Lu
2022-08-23T06:24:12Z

On 2022/8/17 09:10, Lu Baolu wrote:
> The translation table copying code for kdump kernels is currently based
> on the extended root/context entry formats of ECS mode defined in older
> VT-d v2.5, and doesn't handle the scalable mode formats. This causes
> the kexec capture kernel boot failure with DMAR faults if the IOMMU was
> enabled in scalable mode by the previous kernel.
>
> The ECS mode has already been deprecated by the VT-d spec since v3.0 and
> Intel IOMMU driver doesn't support this mode as there's no real hardware
> implementation. Hence this converts ECS checking in copying table code
> into scalable mode.
>
> The existing copying code consumes a bit in the context entry as a mark
> of copied entry. This marker needs to work for the old format as well as
> for extended context entries. It's hard to find such a bit for both
> legacy and scalable mode context entries. This replaces it with a per-
> IOMMU bitmap.
>
> Fixes: 7373a8cc38197 ("iommu/vt-d: Setup context and enable RID2PASID support")
> Cc:stable@vger.kernel.org
> Reported-by: Jerry Snitselaar<jsnitsel@redhat.com>
> Tested-by: Wen Jin<wen.jin@intel.com>
> Signed-off-by: Lu Baolu<baolu.lu@linux.intel.com>

This patch has been queued:

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

Best regards,
baolu