bootdevice: add Error **errp argument for qemu_boot_set()

It will be useful for checking when we change traditional
boot order dynamically and propagate error message
to the monitor.

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>

bootdevice.c

@@ -47,12 +47,18 @@ void qemu_register_boot_set(QEMUBootSetHandler *func, void *opaque)
     boot_set_opaque = opaque;
 }
 
-int qemu_boot_set(const char *boot_order)
+void qemu_boot_set(const char *boot_order, Error **errp)
 {
     if (!boot_set_handler) {
-        return -EINVAL;
+        error_setg(errp, "no function defined to set boot device list for"
+                         " this architecture");
+        return;
+    }
+
+    if (boot_set_handler(boot_set_opaque, boot_order)) {
+        error_setg(errp, "setting boot device list failed");
+        return;
     }
-    return boot_set_handler(boot_set_opaque, boot_order);
 }
 
 void validate_bootdevices(const char *devices, Error **errp)
@@ -94,7 +100,7 @@ void restore_boot_order(void *opaque)
         return;
     }
 
-    qemu_boot_set(normal_boot_order);
+    qemu_boot_set(normal_boot_order, NULL);
 
     qemu_unregister_reset(restore_boot_order, normal_boot_order);
     g_free(normal_boot_order);

include/sysemu/sysemu.h

@@ -223,7 +223,7 @@ void validate_bootdevices(const char *devices, Error **errp);
 /* return 0 if success */
 typedef int QEMUBootSetHandler(void *opaque, const char *boot_order);
 void qemu_register_boot_set(QEMUBootSetHandler *func, void *opaque);
-int qemu_boot_set(const char *boot_order);
+void qemu_boot_set(const char *boot_order, Error **errp);
 
 QemuOpts *qemu_get_machine_opts(void);
 

monitor.c

@@ -1494,17 +1494,15 @@ static void do_ioport_write(Monitor *mon, const QDict *qdict)
 
 static void do_boot_set(Monitor *mon, const QDict *qdict)
 {
-    int res;
+    Error *local_err = NULL;
     const char *bootdevice = qdict_get_str(qdict, "bootdevice");
 
-    res = qemu_boot_set(bootdevice);
-    if (res == 0) {
-        monitor_printf(mon, "boot device list now set to %s\n", bootdevice);
-    } else if (res > 0) {
-        monitor_printf(mon, "setting boot device list failed\n");
+    qemu_boot_set(bootdevice, &local_err);
+    if (local_err) {
+        monitor_printf(mon, "%s\n", error_get_pretty(local_err));
+        error_free(local_err);
     } else {
-        monitor_printf(mon, "no function defined to set boot device list for "
-                       "this architecture\n");
+        monitor_printf(mon, "boot device list now set to %s\n", bootdevice);
     }
 }