[PATCH v5 06/13] iommufd: Allow pt_id to carry viommu_id for IOMMU_HWPT_ALLOC

[Tian, Kevin]

> From: Nicolin Chen <nicolinc at nvidia.com>
> Sent: Saturday, October 26, 2024 7:50 AM
> 
> Now a vIOMMU holds a shareable nesting parent HWPT. So, it can act like
> that nesting parent HWPT to allocate a nested HWPT.
> 
> Support that in the IOMMU_HWPT_ALLOC ioctl handler, and update its kdoc.
> 
> Also, add an iommufd_hwpt_nested_alloc_for_viommu helper to allocate a

the helper name is not updated.

> nested HWPT for a vIOMMU object. Since a vIOMMU object holds the parent
> hwpt's refcount already, increase the refcount of the vIOMMU only.
> 
> Signed-off-by: Nicolin Chen <nicolinc at nvidia.com>

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