diff --git a/tests/virt_autotest/guest_installation_run.pm b/tests/virt_autotest/guest_installation_run.pm
index 3fe713bbd276..b7af9420ff6b 100644
--- a/tests/virt_autotest/guest_installation_run.pm
+++ b/tests/virt_autotest/guest_installation_run.pm
@@ -36,7 +36,7 @@ sub get_script_run {
     handle_sp_in_settings_with_fcs("GUEST_PATTERN");
     my $guest_pattern = get_var('GUEST_PATTERN', 'sles-12-sp2-64-[p|f]v-def-net');
     my $parallel_num = get_var("PARALLEL_NUM", "2");
-    my ($regcode, $regcode_ltss) = get_guest_regcode(separator => '|');
+    my ($regcode, $regcode_ltss) = get_guest_regcode();
     $pre_test_cmd .= " -f \"" . $guest_pattern . "\" -n " . $parallel_num . " -r " . " -e \"" . $regcode . "\" -E \"" . $regcode_ltss . "\"";
     $pre_test_cmd .= " 2>&1 | tee /tmp/s390x_guest_install_test.log" if (is_s390x);