diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index 0e8a33c696..dbae7d74ba 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -242,7 +242,7 @@ _make_test_img()
     if [ $IMGPROTO = "nbd" ]; then
         # Pass a sufficiently high number to -e that should be enough for all
         # tests
-        eval "$QEMU_NBD -v -t -b 127.0.0.1 -p 10810 -f $IMGFMT -e 42  $TEST_IMG_FILE >/dev/null &"
+        eval "$QEMU_NBD -v -t -b 127.0.0.1 -p 10810 -f $IMGFMT -e 42 -x '' $TEST_IMG_FILE >/dev/null &"
         sleep 1 # FIXME: qemu-nbd needs to be listening before we continue
     fi