Re: [PATCH 3/4] iommu: Introduce IOMMU call-back for processing struct KVM assigned to VFIO

[Suthikulpanit, Suravee]

Hi Robin,

On 1/10/2023 10:11 PM, Robin Murphy wrote:
> On 2023-01-10 14:31, Suravee Suthikulpanit wrote:
> > Currently, VFIO provide an kvm_vfio_file_set_kvm() interface for 
> > assigning
> > a KVM structure to a VFIO group. The information in struct KVM is also
> > useful for IOMMU drivers when setting up VFIO domain.
> >
> > Introduce struct iommu_domain_ops.set_kvm call-back function to allow
> > IOMMU drivers to provide call-back to process the struct KVM assigned.
>
> Hmm, it sounds like this has quite some overlap of intent with the 
> existing "enable_nesting" op, and my gut feeling is that it's not great 
> to have two completely different "this is a VFIO domain" mechanisms... :/
>
> Robin.

Actually, the intention is to communicate KVM information, which is 
already available to the VFIO down to the AMD IOMMU driver layer. I am 
not sure if the enable_nesting() has enough information or the same 
intention since that only communicates VFIO domain information.

Thanks,
Suravee