On Thu, 29 Oct 2020 19:29:35 -0400 Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote: > >> @@ -1177,7 +1166,10 @@ static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev) > >> */ > >> if (ret) > >> rc = ret; > >> - vfio_ap_irq_disable_apqn(AP_MKQID(apid, apqi)); > >> + q = vfio_ap_get_queue(matrix_mdev, > >> + AP_MKQID(apid, apqi)); > >> + if (q) > >> + vfio_ap_free_aqic_resources(q); [..] > > > > Under what circumstances do we expect !q? If we don't, then we need to > > complain one way or another. > > In the current code (i.e., prior to introducing the subsequent hot > plug patches), an APQN can not be assigned to an mdev unless it > references a queue device bound to the vfio_ap device driver; however, > there is nothing preventing a queue device from getting unbound > while the guest is running (one of the problems mostly resolved by this > series). In that case, q would be NULL. But if the queue does not belong to us any more it does not make sense call vfio_ap_mdev_reset_queue() on it's APQN, or? I think we should have if(!q) continue; at the very beginning of the loop body, or we want to be sure that q is not null.
