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

[Jason Gunthorpe]

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?

Jason