RE: [PATCH v7 6/6] Documentation: Update VFIO NOIOMMU mode

[Tian, Kevin]

> From: Jacob Pan <jacob.pan@xxxxxxxxxxxxxxxxxxx>
> Sent: Wednesday, June 3, 2026 1:45 PM
> +
> +* IOMMUFD UAPI is available for VFIO device cdev to pin and map user
> memory with
> +  the ability to retrieve physical addresses for DMA command submission.

and no need of mlock.

> +
> +A new IOMMUFD ioctl IOMMU_IOAS_NOIOMMU_GET_PA is added to
> retrieve the physical
> +address for a given IOVA. Although there is no physical DMA remapping
> hardware,
> +IOMMU_IOAS_MAP_FIXED_IOVA is still used to establish IOVA-to-PA
> mappings in the
> +software page table for later IOMMU_IOAS_NOIOMMU_GET_PA lookups.
> +tools/testing/selftests/vfio/vfio_iommufd_noiommu_test.c provides an
> example of
> +using this ioctl in no-IOMMU mode.
> +

the test case doesn't exist yet.

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