Re: [PATCH v5 05/13] iommufd: Allow hwpt_id to carry viommu_id for IOMMU_HWPT_INVALIDATE

[Nicolin Chen <nicolinc@xxxxxxxxxx>]

On Tue, Oct 29, 2024 at 04:09:41PM -0300, Jason Gunthorpe wrote:
> On Fri, Oct 25, 2024 at 04:50:34PM -0700, Nicolin Chen wrote:
> > @@ -497,17 +497,35 @@ int iommufd_hwpt_invalidate(struct iommufd_ucmd *ucmd)
> >  		goto out;
> >  	}
> >  
> > -	hwpt = iommufd_get_hwpt_nested(ucmd, cmd->hwpt_id);
> > -	if (IS_ERR(hwpt)) {
> > -		rc = PTR_ERR(hwpt);
> > +	pt_obj = iommufd_get_object(ucmd->ictx, cmd->hwpt_id, IOMMUFD_OBJ_ANY);
> > +	if (IS_ERR(pt_obj)) {
> > +		rc = PTR_ERR(pt_obj);
> >  		goto out;
> >  	}
> > +	if (pt_obj->type == IOMMUFD_OBJ_HWPT_NESTED) {
> > +		struct iommufd_hw_pagetable *hwpt =
> > +			container_of(pt_obj, struct iommufd_hw_pagetable, obj);
> > +
> > +		rc = hwpt->domain->ops->cache_invalidate_user(hwpt->domain,
> > +							      &data_array);
> > +	} else if (pt_obj->type == IOMMUFD_OBJ_VIOMMU) {
> > +		struct iommufd_viommu *viommu =
> > +			container_of(pt_obj, struct iommufd_viommu, obj);
> > +
> > +		if (!viommu->ops || !viommu->ops->cache_invalidate) {
> > +			rc = -EOPNOTSUPP;
> > +			goto out_put_pt;
> > +		}
> > +		rc = viommu->ops->cache_invalidate(viommu, &data_array);
> > +	} else {
> > +		rc = -EINVAL;
> > +		goto out_put_pt;
> > +	}
> 
> Given the test in iommufd_viommu_alloc_hwpt_nested() is:
> 
> 	if (WARN_ON_ONCE(hwpt->domain->type != IOMMU_DOMAIN_NESTED ||
> 			 (!viommu->ops->cache_invalidate &&
> 			  !hwpt->domain->ops->cache_invalidate_user)))
> 			  {
> 
> We will crash if the user passes a viommu allocated domain as
> IOMMUFD_OBJ_HWPT_NESTED since the above doesn't check it.

Ah, that was missed.

> I suggest we put the required if (ops..) -EOPNOTSUPP above and remove
> the ops->cache_invalidate checks from both WARN_ONs.

Ack. I will add hwpt->domain->ops check:
---------------------------------------------------------------------
	if (pt_obj->type == IOMMUFD_OBJ_HWPT_NESTED) {
		struct iommufd_hw_pagetable *hwpt =
			container_of(pt_obj, struct iommufd_hw_pagetable, obj);
	
		if (!hwpt->domain->ops ||
		    !hwpt->domain->ops->cache_invalidate_user) {
			rc = -EOPNOTSUPP;
			goto out_put_pt;
		}
		rc = hwpt->domain->ops->cache_invalidate_user(hwpt->domain,
							      &data_array);
	} else if (pt_obj->type == IOMMUFD_OBJ_VIOMMU) {
		struct iommufd_viommu *viommu =
			container_of(pt_obj, struct iommufd_viommu, obj);
	
		if (!viommu->ops || !viommu->ops->cache_invalidate) {
			rc = -EOPNOTSUPP;
			goto out_put_pt;
		}
		rc = viommu->ops->cache_invalidate(viommu, &data_array);
	} else {
---------------------------------------------------------------------

Thanks
Nicolin