Re: [PATCH v2 03/11] iommufd/hw_pagetable: Use domain_alloc_user op for domain allocation

[Nicolin Chen]

On Fri, May 19, 2023 at 08:56:25AM +0000, Tian, Kevin wrote:
 
> > From: Yi Liu <yi.l.liu@xxxxxxxxx>
> > Sent: Thursday, May 11, 2023 10:39 PM
> >
> >
> > @@ -88,7 +90,10 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx
> > *ictx, struct iommufd_ioas *ioas,
> >       refcount_inc(&ioas->obj.users);
> >       hwpt->ioas = ioas;
> >
> > -     hwpt->domain = iommu_domain_alloc(idev->dev->bus);
> > +     if (ops->domain_alloc_user)
> > +             hwpt->domain = ops->domain_alloc_user(idev->dev, NULL,
> > NULL);
> > +     else
> > +             hwpt->domain = iommu_domain_alloc(idev->dev->bus);
> 
> this reminds the comment for @domain_alloc_user() should clarify
> that UNMANGED domain type is assumed when no user data is
> provided, to be compatible with iommu_domain_alloc().

Yes. Perhaps:

 * @domain_alloc_user: allocate user iommu domain. A valid user_data pointer and
 *                     a parent pointer to a kernel-managed domain are required
 *                     to allocate an IOMMU_DOMAIN_NESTED domain. Otherwise, the
 *                     new domain will be set to an IOMMU_DOMAIN_UNMANAGED type.

Thanks
Nic