[Intel-gfx] [PATCH v2 07/11] vfio-iommufd: Support iommufd for physical VFIO devices

[Jason Gunthorpe]

On Mon, Nov 07, 2022 at 10:10:59PM -0800, Nicolin Chen wrote:

> > @@ -812,6 +821,7 @@ static int vfio_device_first_open(struct vfio_device *device)
> >  	device->kvm = NULL;
> >  	if (device->group->container)
> >  		vfio_group_unuse_container(device->group);
> > +	vfio_iommufd_unbind(device);
> 
> ...yet, missing here, which could result in kernel oops.
> 
> Should probably add something similar:
> +	if (device->group->iommufd)
> +		vfio_iommufd_unbind(device);
> 
> Or should check !vdev->iommufd_device inside the ->unbind.

Lets keep it symmetric since the container is checked:

@@ -821,7 +821,8 @@ static int vfio_device_first_open(struct vfio_device *device)
        device->kvm = NULL;
        if (device->group->container)
                vfio_group_unuse_container(device->group);
-       vfio_iommufd_unbind(device);
+       else if (device->group->iommufd)
+               vfio_iommufd_unbind(device);
 err_module_put:
        mutex_unlock(&device->group->group_lock);
        module_put(device->dev->driver->owner);
@@ -840,7 +841,8 @@ static void vfio_device_last_close(struct vfio_device *device)
        device->kvm = NULL;
        if (device->group->container)
                vfio_group_unuse_container(device->group);
-       vfio_iommufd_unbind(device);
+       else if (device->group->iommufd)
+               vfio_iommufd_unbind(device);
        mutex_unlock(&device->group->group_lock);
        module_put(device->dev->driver->owner);

Thanks,
Jason