On Thu, 29 Oct 2020 19:29:35 -0400 Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote: > On 10/27/20 2:48 AM, Halil Pasic wrote: > > On Thu, 22 Oct 2020 13:11:56 -0400 > > Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote: > > > >> The queues assigned to a matrix mediated device are currently reset when: > >> > >> * The VFIO_DEVICE_RESET ioctl is invoked > >> * The mdev fd is closed by userspace (QEMU) > >> * The mdev is removed from sysfs. > > What about the situation when vfio_ap_mdev_group_notifier() is called to > > tell us that our pointer to KVM is about to become invalid? Do we need to > > clean up the IRQ stuff there? > > After reading this question, I decided to do some tracing using > printk's and learned that the vfio_ap_mdev_group_notifier() > function does not get called when the guest is shutdown. The reason > for this is because the vfio_ap_mdev_release() function, which is called > before the KVM pointer is invalidated, unregisters the group notifier. > > I took a look at some of the other drivers that register a group > notifier in the mdev_parent_ops.open callback and each unregistered > the notifier in the mdev_parent_ops.release callback. > > So, to answer your question, there is no need to cleanup the IRQ > stuff in the vfio_ap_mdev_group_notifier() function since it will > not get called when the KVM pointer is invalidated. The cleanup > should be done in the vfio_ap_mdev_release() function that gets > called when the mdev fd is closed. You say if vfio_ap_mdev_group_notifier() is called to tell us that KVM going away, then it is a bug? If that is the case, I would like that reflected in the code! By that I mean at logging an error at least (if not BUG_ON). Regards, Halil
