RE: [PATCH v3 4/9] iommu/arm-smmu-v3: Report IOMMU_CAP_ENFORCE_CACHE_COHERENCY for CANWBS

Tian, Kevin
2024-10-24T07:41:39Z

> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Thursday, October 10, 2024 12:23 AM
>
> HW with CANWBS is always cache coherent and ignores PCI No Snoop
> requests
> as well. This meets the requirement for
> IOMMU_CAP_ENFORCE_CACHE_COHERENCY,
> so let's return it.
>
> Implement the enforce_cache_coherency() op to reject attaching devices
> that don't have CANWBS.
>
> Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
> Reviewed-by: Mostafa Saleh <smostafa@google.com>
> Tested-by: Nicolin Chen <nicolinc@nvidia.com>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>