Re: [PATCH v1 4/4] iommu/arm-smmu-v3-iommufd: Allow a shared s2_parent to allocate vSMMU

[Nicolin Chen]

On Wed, Mar 05, 2025 at 12:57:43PM -0400, Jason Gunthorpe wrote:
> On Wed, Mar 05, 2025 at 09:01:40AM +0000, Shameerali Kolothum Thodi wrote:
> 
> > >  	if (!(smmu->features & ARM_SMMU_FEAT_NESTING))
> > >  		return ERR_PTR(-EOPNOTSUPP);
> > > 
> > > -	if (s2_parent->smmu != master->smmu)
> > > -		return ERR_PTR(-EINVAL);
> > > -
> > 
> > Not sure we can just relax this like this. What if the two physical SMMUs are different in
> > functionality/features? Do we need some kind of sanity check here?
> 
> Yes, a function to check if a domain's iopgtbl config is compatible
> with the instance is required.

Yea. Will rework.

Thanks!
Nicolin