RE: [PATCH v4 15/32] vfio: introduce KVM-owned IOMMU type

[Tian, Kevin]

> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Tuesday, March 15, 2022 10:55 PM
> 
> The first level iommu_domain has the 'type1' map and unmap and pins
> the pages. This is the 1:1 map with the GPA and ends up pinning all
> guest memory because the point is you don't want to take a memory pin
> on your performance path
> 
> The second level iommu_domain points to a single IO page table in GPA
> and is created/destroyed whenever the guest traps to the hypervisor to
> manipulate the anchor (ie the GPA of the guest IO page table).
> 

Can we use consistent terms as used in iommufd and hardware, i.e.
with first-level/stage-1 referring to the child (GIOVA->GPA) which is
further nested on second-level/stage-2 as the parent (GPA->HPA)?

Otherwise all other explanations are agreed.

Thanks
Kevin