Re: [PATCH v9 3/4] iommu/arm-smmu-v3-iommufd: Report CFGI/TLBI-repeat erratum

On Sun, Jul 26, 2026 at 08:19:03AM +0000, Ashish Mhetre wrote:

A guest with access to VCMDQ generates its own invalidation commands
and must apply any invalidation errata before submitting them. If the
host also repeats those commands, each affected invalidation is issued
four times instead of twice.

Add IOMMU_HW_INFO_ARM_SMMUV3_ERRATA_REPEAT_TLBI_CFGI to report the
CFGI/TLBI-repeat erratum to user space. This allows the VMM to expose
the erratum to the guest or apply the workaround itself.

Use the raw __arm_smmu_cmdq_issue_cmdlist() helper for user-provided
invalidations so the host does not apply the workaround a second time.
Add arm_smmu_erratum_repeat_tlbi_cfgi() to query the static key when
populating the SMMUv3 hardware information.

Signed-off-by: Ashish Mhetre <redacted>

Reviewed-by: Nicolin Chen <redacted>