RE: [PATCH v3 04/17] iommufd: Pass in hwpt_type/parent/user_data to iommufd_hw_pagetable_alloc()

[Tian, Kevin]

> From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> Sent: Monday, July 24, 2023 7:04 PM
> 
> Nested translation has stage-1 and stage-2 page tables. A stage-1 page
> table is managed by user space, and it needs to work with a stage-2 page
> table, which is a parent hwpt for the stage-1 hwpt.
> 
> iommu core already supports accepting parent iommu_domain and
> user_data
> to allocate an iommu_domain. This makes iommufd_hw_pagetable_alloc()
> to
> accept the parent hwpt and user_data, and relays them to iommu core, to
> prepare for supporting hw_pagetable allocation with user_data.
> 
> Also, add a parent pointer in struct iommufd_hw_pagetable for taking and
> releasing its refcount.
> 
> Co-developed-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>

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