Re: [PATCH v4 2/9] iommu: Replace sva_iommu with iommu_attach_handle

Jason Gunthorpe
2024-04-08T14:19:49Z

On Sat, Apr 06, 2024 at 02:09:34PM +0800, Baolu Lu wrote:
> On 4/3/24 7:59 PM, Jason Gunthorpe wrote:
> > On Wed, Apr 03, 2024 at 09:15:12AM +0800, Lu Baolu wrote:
> > > + /* A bond already exists, just take a reference`. */
> > > + handle = iommu_attach_handle_get(group, iommu_mm->pasid);
> > > + if (handle) {
> > > + mutex_unlock(&iommu_sva_lock);
> > > + return handle;
> > > }
> > At least in this context this is not enough we need to ensure that the
> > domain on the PASID is actually an SVA domain and it was installed by
> > this mechanism, not an iommufd domain for instance.
> >
> > ie you probably need a type field in the iommu_attach_handle to tell
> > what the priv is.
> >
> > Otherwise this seems like a great idea!
>
> Yes, you are right. For the SVA case, I will add the following changes.
> The IOMMUFD path will also need such enhancement. I will update it in
> the next version.

The only use for this is the PRI callbacks right? Maybe instead of
adding a handle type let's just check domain->iopf_handler ?

Ie SVA will pass &ommu_sva_iopf_handler as its "type"

Jason