Re: [PATCH 0/2] iommu/amd: Use MAX buffer size when SNP is enabled on Family 0x19

On Mon, 20 Apr 2026 08:42:02 +0000 Vasant Hegde <[email protected]> wrote:

> This series addresses CVE-2023-20585 [1] by increasing the AMD IOMMU
> Event log and PPR log buffer sizes to the maximum supported value (512K)
> on affected CPU families when SNP is enabled.
> 
> Use MAX buffer size when SNP is enabled on Milan/Genoa. Impacted buffers:
>   - Milan : Event log (PPR/GALog is not supported when SNP is enabled)
>   - Genoa : Event and PPR log (GALog is not supported when SNP is enabled)
>

Hi,

This series seems to break kexec in our production on Milan hosts with SEV enabled.
This is on the 6.18.43 stable kernel backport.

If on top of 6.18.43 release, we revert the 2 commits, i.e.
Revert "iommu/amd: Use maximum PPR log buffer size when SNP is enabled on Family 0x19"
Revert "iommu/amd: Use maximum Event log buffer size when SNP is enabled on Family 0x19"

kexec starts working again.

Could you help in fixing this issue?

Thanks

> [1] https://www.amd.com/en/resources/product-security/bulletin/amd-sb-3016.html
> 
> Cc: Borislav Petkov <[email protected]>
> Cc: Suravee Suthikulpanit <[email protected]>
> Cc: Joerg Roedel <[email protected]>
> 
> Vasant Hegde (2):
>   iommu/amd: Use maximum Event log buffer size when SNP is enabled on Family 0x19
>   iommu/amd: Use maximum PPR log buffer size when SNP is enabled on Family 0x19
> 
>  drivers/iommu/amd/amd_iommu.h       |   3 +
>  drivers/iommu/amd/amd_iommu_types.h |  21 +++--
>  drivers/iommu/amd/init.c            | 123 ++++++++++++++++++++--------
>  drivers/iommu/amd/iommu.c           |   2 +-
>  drivers/iommu/amd/ppr.c             |   8 +-
>  5 files changed, 110 insertions(+), 47 deletions(-)
> 
> -- 
> 2.31.1
> 
>