virtio-scsi: do not crash on adding buffers to the event queue

The event queue is not supported yet and the handler does not
have to do much anyway when buffers are added.  However, the
handler is called unconditionally by the virtio layer, and this
results in a crash as soon as buffers are added to the event
queue because we pass NULL.

Reported-by: Bryan Venteicher <bryanv@daemoninthecloset.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/hw/virtio-scsi.c b/hw/virtio-scsi.c
index e1a767ea78d4d7285a0a7acfa39e24ee1ab66474..0a5ac40e2f5273db522ea3fbc1a506c4512e340b 100644 (file)
--- a/hw/virtio-scsi.c
+++ b/hw/virtio-scsi.c
@@ -405,6 +405,10 @@ static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
     }
 }
 
+static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
+{
+}
+
 static void virtio_scsi_command_complete(SCSIRequest *r, uint32_t status,
                                          size_t resid)
 {
@@ -609,7 +613,7 @@ VirtIODevice *virtio_scsi_init(DeviceState *dev, VirtIOSCSIConf *proxyconf)
     s->ctrl_vq = virtio_add_queue(&s->vdev, VIRTIO_SCSI_VQ_SIZE,
                                    virtio_scsi_handle_ctrl);
     s->event_vq = virtio_add_queue(&s->vdev, VIRTIO_SCSI_VQ_SIZE,
-                                   NULL);
+                                   virtio_scsi_handle_event);
     for (i = 0; i < s->conf->num_queues; i++) {
         s->cmd_vqs[i] = virtio_add_queue(&s->vdev, VIRTIO_SCSI_VQ_SIZE,
                                          virtio_scsi_handle_cmd);