Re: [RFC PATCH v6 05/11] iommu: Add a helper to validate a vIOMMU parent

[Jacob Pan <jacob.pan@linux.microsoft.com>]

Hi Jason,

On Tue, 29 Sep 2026 09:30:48 -0300
Jason Gunthorpe <jgg@nvidia.com> wrote:

> On Mon, Sep 28, 2026 at 10:55:24PM -0700, Jacob Pan wrote:
> 
> > Also, we don't have a T=0 to T=1 transition, our intended external
> > attach can be transitioned from a blocked domain, not from a paging
> > domain to external.  
> 
> You kind of do, external is close to T=1..
> 
> > > I think you are going to have module dependency issues trying to
> > > get the mshv driver's info into the iommu driver, adding a "TSM"
> > > like driver would resolve that. ie mshv could just provide the
> > > viommu. 
> > I introduced a similar registration interface in hv-common to solve
> > the module dep issue. Will look into if I can leverage the vIOMMU
> > helper here.  
> 
> That doesn't sound so nice..
> 
> If we have to have registrations it is better to have the viommu
> registration that Aneesh drafted than several schemes inside specific
> drivers..
Agreed. Now that the commonality with the TSM provider path is clear, I
will adapt the MSHV support to use the generic vIOMMU provider
registration.