Re: [PATCH v1] s390/virtio_ccw: don't allocate/assign airqs for non-existing queues

On Fri, Apr 04, 2025 at 05:39:10PM +0200, Halil Pasic wrote:

That basically means that if I was, for the sake of fun do

--- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -1197,7 +1197,6 @@ static unsigned int features[] = { VIRTIO_BALLOON_F_MUST_TELL_HOST, VIRTIO_BALLOON_F_STATS_VQ, VIRTIO_BALLOON_F_DEFLATE_ON_OOM,

•   VIRTIO_BALLOON_F_FREE_PAGE_HINT,
    VIRTIO_BALLOON_F_PAGE_POISON,
    VIRTIO_BALLOON_F_REPORTING,
  

};

I would end up with virtio_check_driver_offered_feature() calling BUG().

I mean, yes, this is exactly to catch drivers that use features without negotiating them first.