From: Paolo Bonzini <pbonz...@redhat.com> If the vring has not been set up, it is not necessary for vring_used_idx to do anything (as is already the case when the caller is virtio_load). This is harmless for now, but it will be a problem when the MemoryRegionCache has not been set up.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org> Reviewed-by: Michael S. Tsirkin <m...@redhat.com> Signed-off-by: Michael S. Tsirkin <m...@redhat.com> --- hw/virtio/virtio.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index d62509d..cdafcec 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2156,7 +2156,9 @@ void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx) void virtio_queue_update_used_idx(VirtIODevice *vdev, int n) { - vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]); + if (vdev->vq[n].vring.desc) { + vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]); + } } void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n) -- MST