hw/core: Restrict hotplug to system emulation

Restrict hotplug to system emulation, add stubs for the other uses.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Yanan Wang <wangyanan55@huawei.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20211028150521.1973821-5-philmd@redhat.com>

hw/core/hotplug-stubs.c

+/*
+ * Hotplug handler stubs
+ *
+ * Copyright (c) Red Hat
+ *
+ * Authors:
+ *  Philippe Mathieu-Daudé <philmd@redhat.com>,
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#include "qemu/osdep.h"
+#include "hw/qdev-core.h"
+
+HotplugHandler *qdev_get_hotplug_handler(DeviceState *dev)
+{
+    return NULL;
+}
+
+void hotplug_handler_pre_plug(HotplugHandler *plug_handler,
+                              DeviceState *plugged_dev,
+                              Error **errp)
+{
+    g_assert_not_reached();
+}
+
+void hotplug_handler_plug(HotplugHandler *plug_handler,
+                          DeviceState *plugged_dev,
+                          Error **errp)
+{
+    g_assert_not_reached();
+}

hw/core/meson.build

 # core qdev-related obj files, also used by *-user and unit tests
 hwcore_ss.add(files(
   'bus.c',
-  'hotplug.c',
   'qdev-properties.c',
   'qdev.c',
   'reset.c',
@@ -11,8 +10,17 @@ hwcore_ss.add(files(
   'irq.c',
   'clock.c',
   'qdev-clock.c',
-  'qdev-hotplug.c',
 ))
+if have_system
+  hwcore_ss.add(files(
+    'hotplug.c',
+    'qdev-hotplug.c',
+  ))
+else
+  hwcore_ss.add(files(
+    'hotplug-stubs.c',
+  ))
+endif
 
 common_ss.add(files('cpu-common.c'))
 softmmu_ss.add(when: 'CONFIG_FITLOADER', if_true: files('loader-fit.c'))