RE: [PATCH RFC v3 04/12] iommu/sva: Basic data structures for SVA

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Sunday, April 10, 2022 6:25 PM
> 
> Use below data structures for SVA implementation in the IOMMU core:
> 
> - struct iommu_sva_ioas
>   Represent the I/O address space shared with an application CPU address
>   space. This structure has a 1:1 relationship with an mm_struct. It
>   graps a "mm->mm_count" refcount during creation and drop it on release.
> 
> - struct iommu_domain (IOMMU_DOMAIN_SVA type)
>   Represent a hardware pagetable that the IOMMU hardware could use for
>   SVA translation. Multiple iommu domains could be bound with an SVA ioas
>   and each graps a refcount from ioas in order to make sure ioas could
>   only be freed after all domains have been unbound.
> 
> - struct iommu_sva
>   Represent a bond relationship between an SVA ioas and an iommu domain.
>   If a bond already exists, it's reused and a reference is taken.
> 
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>

This should be patch07. None of following patches touch those structures
until hitting patch08.