Re: [PATCH v1 7/8] iommufd/device: Use iommu_group_replace_domain()

[Nicolin Chen <nicolinc@nvidia.com>]

On Mon, Feb 06, 2023 at 08:46:04AM +0000, Tian, Kevin wrote:
> > From: Nicolin Chen <nicolinc@nvidia.com>
> > Sent: Thursday, February 2, 2023 3:05 PM
> >
> > @@ -246,6 +249,18 @@ static int iommufd_device_do_attach(struct
> > iommufd_device *idev,
> >               }
> >       }
> >
> > +     if (cur_hwpt) {
> > +             /* Replace the cur_hwpt */
> > +             mutex_lock(&cur_hwpt->devices_lock);
> > +             if (cur_hwpt->ioas != hwpt->ioas)
> > +                     iopt_remove_reserved_iova(&cur_hwpt->ioas->iopt,
> > +                                               idev->dev);
> > +             list_del(&cur_hwpt->hwpt_item);
> 
> emmm shouldn't this be done only when the device is the last
> one attached to the hwpt? and if it's the last one you should
> also iopt_table_remove_domain() together with list_del, i.e.
> similar housekeeping as done in iommufd_device_detach().

You are right. I had another patch on top of this series,
moving this list_del() and iopt_table_remove_domain() to
the destroy() callback, so I overlooked.

And I just found that the list_add_del(hwpt_item) in the
IOMMUFD_OBJ_HW_PAGETABLE case doesn't seem to call at the
first device's attachment. So, I think that we might need
my previous "symmetric" patch in this series too.

Will fix in v2. Thanks!

Nic