On Fri, Mar 10, 2023 at 11:48:58AM +0000, Tian, Kevin wrote:
> > From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> > Sent: Wednesday, March 8, 2023 8:36 AM
> >
> > @@ -359,6 +360,76 @@ iommufd_device_do_attach(struct iommufd_device
> > *idev,
> > return NULL;
> > }
> >
> > +static struct iommufd_hw_pagetable *
> > +iommufd_device_do_replace(struct iommufd_device *idev,
> > + struct iommufd_hw_pagetable *hwpt)
> > +{
> > + struct iommufd_group *igroup = idev->igroup;
> > + struct iommufd_hw_pagetable *old_hwpt;
> > + unsigned int num_devices = 0;
> > + struct iommufd_device *cur;
> > + int rc;
> > +
> > + mutex_lock(&idev->igroup->lock);
> > +
> > + if (hwpt == igroup->hwpt) {
> > + mutex_unlock(&idev->igroup->lock);
> > + return NULL;
> > + }
> > +
> > + /* Try to upgrade the domain we have */
> > + list_for_each_entry(cur, &igroup->device_list, group_item) {
> > + num_devices++;
> > + if (cur->enforce_cache_coherency) {
> > + rc = iommufd_hw_pagetable_enforce_cc(hwpt);
> > + if (rc)
> > + goto err_unlock;
> > + }
> > + }
> > +
> > + old_hwpt = igroup->hwpt;
> > + if (hwpt->ioas != old_hwpt->ioas) {
>
> Do we allow this function to be used as attach/detach?
No. NULL is never a valid input..
> if yes old_hwpt could be NULL here.
Er that test got lost in the last version it is neeed
> and looks the policy for physical attach is different from the one that
> Nicoline applies for access. iommufd_access_set_ioas() can behave
> like normal attach/detach.
Access should change.
Thanks,
Jason
