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

[Tian, Kevin]

> From: Jason Gunthorpe <jgg at 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 at nvidia.com>
> Reviewed-by: Mostafa Saleh <smostafa at google.com>
> Tested-by: Nicolin Chen <nicolinc at nvidia.com>
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>

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