diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
index 8e93b0a707..5249a628cc 100644
--- a/tests/qtest/libqtest.c
+++ b/tests/qtest/libqtest.c
@@ -1279,7 +1279,7 @@ void qtest_cb_for_every_machine(void (*cb)(const char *machine),
         g_assert(qstr);
         mname = qstring_get_str(qstr);
         /* Ignore machines that cannot be used for qtests */
-        if (!memcmp("xenfv", mname, 5) || g_str_equal("xenpv", mname)) {
+        if (!strncmp("xenfv", mname, 5) || g_str_equal("xenpv", mname)) {
             continue;
         }
         if (!skip_old_versioned || !qtest_is_old_versioned_machine(mname)) {