On Mon, 7 Jan 2019 16:06:32 +0100 Cornelia Huck <cohuck@xxxxxxxxxx> wrote: > On Mon, 7 Jan 2019 13:31:46 +0100 > Halil Pasic <pasic@xxxxxxxxxxxxx> wrote: > > > A queue with a capacity of zero is clearly not a valid virtio queue. > > Some emulators report zero queue size if queried with an invalid queue > > index. Instead of crashing in this case let us just return -EINVAL. To > > s/-EINVAL/-ENOENT/ > So I did forget something, again. :/ Thanks for spotting it! > > make that work properly, let us fix the notifier cleanup logic as well. > > > > Signed-off-by: Halil Pasic <pasic@xxxxxxxxxxxxx> > > --- > > This patch is motivated by commit 86a5597 "virtio-balloon: > > VIRTIO_BALLOON_F_FREE_PAGE_HINT" (Wei Wang, 2018-08-27) which triggered > > the described scenario. The emulator in question is the current QEMU. > > The problem we run into is the underflow in the following loop > > in __vring_new_virtqueue(): > > for (i = 0; i < vring.num-1; i++) > > vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1) > > Namely vring.num is an unsigned int. > > > > RFC --> v1: > > * Change error code from -EINVAL to -ENOENT, so we are in line with the > > other transports. > > * Push down the detection of the error into virtio_ccw_read_vq_conf(). > > --- > > drivers/s390/virtio/virtio_ccw.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > Thanks, applied. > Thanks! Halil
