RE: [RFC 01/13] iommu: Introduce bind_guest_stage API

[Tian, Kevin]

> From: Auger Eric
> Sent: Friday, August 31, 2018 9:52 PM
> 
> Hi Jean-Philippe,
> 
> On 08/31/2018 03:11 PM, Jean-Philippe Brucker wrote:
> > Hi Eric,
> >
> > On 23/08/18 16:25, Auger Eric wrote:
> >>> +int iommu_bind_guest_stage(struct iommu_domain *domain, struct
> device *dev,
> >>> +			   struct iommu_guest_stage_config *cfg)
> >
> > About the name change from iommu_bind_pasid_table: is the intent to
> > reuse this API for SMMUv2, which supports nested but not PASID? Seems
> > like a good idea but "iommu_bind_table" may be better since "stage" is
> > only used by Arm.
> 
> At the moment I don't target SMUv2 but just SMMUv3. My focus was on
> nested stage enablement without enabling the multi-CD feature (PASID),
> whish is not supported by the QEMU vSMMUv3. Afterwards I realized that
> basically we are pointing to a CD or PASID table and that's about the
> same. I don't have a strong opinion on the name, iommu_bind_guest_table
> or iommu_bind_pasid_table would be fine with me. Indeed "stage" is ARM
> vocable (level for Intel?)

Intel uses first level/second level. 

iommu_bind_table is a bit confusing. what should people take table as?
there is PASID table. there is also page table linked in each stage/level. and
maybe other tables in vendor-specific definition.

to me iommu_bind_pasid_table is still clearer. anyway in other places
we've used pasid explicitly in vfio/iommu APIs, then it should be general
enough to represent various implementations.

Thanks
Kevin