diff --git a/monitor.c b/monitor.c
index e960c3831b..598dbfe5f2 100644
--- a/monitor.c
+++ b/monitor.c
@@ -921,11 +921,14 @@ static void do_info_cpus(Monitor *mon, QObject **ret_data)
     *ret_data = QOBJECT(cpu_list);
 }
 
-static void do_cpu_set(Monitor *mon, const QDict *qdict, QObject **ret_data)
+static int do_cpu_set(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
     int index = qdict_get_int(qdict, "index");
-    if (mon_set_cpu(index) < 0)
+    if (mon_set_cpu(index) < 0) {
         qemu_error_new(QERR_INVALID_PARAMETER, "index");
+        return -1;
+    }
+    return 0;
 }
 
 static void do_info_jit(Monitor *mon)
diff --git a/qemu-monitor.hx b/qemu-monitor.hx
index c1bd77335a..835fd05730 100644
--- a/qemu-monitor.hx
+++ b/qemu-monitor.hx
@@ -604,7 +604,7 @@ ETEXI
         .params     = "index",
         .help       = "set the default CPU",
         .user_print = monitor_user_noop,
-        .mhandler.cmd_new = do_cpu_set,
+        .cmd_new_ret = do_cpu_set,
     },
 
 STEXI