[RFT][PATCH v2 9/9] vfio: Replace phys_pfn with pages for vfio_pin_pages()

[Tian, Kevin]

> From: Nicolin Chen <nicolinc at nvidia.com>
> Sent: Wednesday, July 6, 2022 2:28 PM
> 
> Most of the callers of vfio_pin_pages() want "struct page *" and the
> low-level mm code to pin pages returns a list of "struct page *" too.
> So there's no gain in converting "struct page *" to PFN in between.
> 
> Replace the output parameter "phys_pfn" list with a "pages" list, to
> simplify callers. This also allows us to replace the vfio_iommu_type1
> implementation with a more efficient one.

worth mentioning that vfio pin is only for struct page * hence the
pfn_valid() check in gvt can be removed.

> 
> For now, also update vfio_iommu_type1 to fit this new parameter too.
> 
> Signed-off-by: Nicolin Chen <nicolinc at nvidia.com>

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