Index: sys/dev/virtio/scsi/virtio_scsi.c
===================================================================
--- sys/dev/virtio/scsi/virtio_scsi.c
+++ sys/dev/virtio/scsi/virtio_scsi.c
@@ -267,7 +267,7 @@
 {
 	struct vtscsi_softc *sc;
 	struct virtio_scsi_config scsicfg;
-	int error;
+	int error, rqsize;
 
 	sc = device_get_softc(dev);
 	sc->vtscsi_dev = dev;
@@ -311,6 +311,14 @@
 		goto fail;
 	}
 
+	rqsize = virtqueue_size(sc->vtscsi_request_vq);
+	if (sc->vtscsi_max_nsegs > rqsize) {
+		error = E2BIG;
+		device_printf(dev, "max_nsegs is too big (%d > %d)\n",
+		    sc->vtscsi_max_nsegs, rqsize);
+		goto fail;
+	}
+
 	error = vtscsi_init_event_vq(sc);
 	if (error) {
 		device_printf(dev, "cannot populate the eventvq\n");