[PATCH v5 04/13] iommufd/hw_pagetable: Enforce invalidation op on vIOMMU-based hwpt_nested

[Tian, Kevin]

> From: Jason Gunthorpe <jgg at nvidia.com>
> Sent: Wednesday, October 30, 2024 12:05 AM
> 
> On Tue, Oct 29, 2024 at 08:22:43AM +0000, Tian, Kevin wrote:
> > > From: Nicolin Chen <nicolinc at nvidia.com>
> > > Sent: Saturday, October 26, 2024 7:51 AM
> > >
> > > @@ -302,7 +302,9 @@ iommufd_viommu_alloc_hwpt_nested(struct
> > > iommufd_viommu *viommu, u32 flags,
> > >  	}
> > >  	hwpt->domain->owner = viommu->iommu_dev->ops;
> > >
> > > -	if (WARN_ON_ONCE(hwpt->domain->type !=
> > > IOMMU_DOMAIN_NESTED)) {
> > > +	if (WARN_ON_ONCE(hwpt->domain->type !=
> > > IOMMU_DOMAIN_NESTED ||
> > > +			 (!viommu->ops->cache_invalidate &&
> > > +			  !hwpt->domain->ops->cache_invalidate_user))) {
> > >  		rc = -EINVAL;
> > >  		goto out_abort;
> > >  	}
> >
> > According to patch5, cache invalidate in viommu only uses
> > viommu->ops->cache_invalidate. Is here intended to allow
> > nested hwpt created via viommu to still support the old
> > method?
> 
> I think that is reasonable?
> 

Yes, just want to confirm.

Reviewed-by: Kevin Tian <kevin.tian at intel.com>