iommu/amd: Do not flush IRTE when only updating isRun and destination fields

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According to the recent update in the AMD IOMMU spec [1], the IsRun and
Destination fields of the Interrupt Remapping Table Entry (IRTE) are not
cached by the IOMMU hardware.

Therefore, do not issue the INVALIDATE_INTERRUPT_TABLE command when
updating IRTE[IsRun] and IRTE[Destination] when IRTE[GuestMode]=1, which
should help improve IOMMU AVIC/x2AVIC performance.

References:
[1] AMD IOMMU Spec Revision (Rev 3.08-PUB)
(Link: https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/specifications/48882_IOMMU.pdf)

Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Tested-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Link: https://lore.kernel.org/r/20231017144236.8287-1-suravee.suthikulpanit@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

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Suravee Suthikulpanit 2023-10-17 09:42:36 -05:00 • committed by Joerg Roedel

parent 9abe6c5535

commit 57cdb720ea

1 changed files with 16 additions and 4 deletions

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drivers/iommu/amd/iommu.c

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