RE: [PATCH v2 6/8] iommu/arm-smmu-v3: Support IOMMU_GET_HW_INFO via struct arm_smmu_hw_info

Tian, Kevin
2024-08-30T07:56:42Z

> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Tuesday, August 27, 2024 11:52 PM
>
> From: Nicolin Chen <nicolinc@nvidia.com>
>
> For virtualization cases the IDR/IIDR/AIDR values of the actual SMMU
> instance need to be available to the VMM so it can construct an
> appropriate vSMMUv3 that reflects the correct HW capabilities.
>
> For userspace page tables these values are required to constrain the valid
> values within the CD table and the IOPTEs.
>
> The kernel does not sanitize these values. If building a VMM then
> userspace is required to only forward bits into a VM that it knows it can
> implement. Some bits will also require a VMM to detect if appropriate
> kernel support is available such as for ATS and BTM.
>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

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