qom: Create system containers explicitly

Always explicitly create QEMU system containers upfront.

Root containers will be created when trying to fetch the root object the
1st time.  They are:

  /objects
  /chardevs
  /backend

Machine sub-containers will be created only until machine is being
initialized.  They are:

  /machine/unattached
  /machine/peripheral
  /machine/peripheral-anon

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20241121192202.4155849-8-peterx@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

1 files changed, 23 insertions, 1 deletions

diff --git a/qom/object.c b/qom/object.c
index c9f8442b13..b4c52d055d 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1729,12 +1729,34 @@ const char *object_property_get_type(Object *obj, const char *name, Error **errp
     return prop->type;
 }
 
+static const char *const root_containers[] = {
+    "chardevs",
+    "objects",
+    "backend"
+};
+
+static Object *object_root_initialize(void)
+{
+    Object *root = object_new(TYPE_CONTAINER);
+    int i;
+
+    /*
+     * Create all QEMU system containers.  "machine" and its sub-containers
+     * are only created when machine initializes (qemu_create_machine()).
+     */
+    for (i = 0; i < ARRAY_SIZE(root_containers); i++) {
+        object_property_add_new_container(root, root_containers[i]);
+    }
+
+    return root;
+}
+
 Object *object_get_root(void)
 {
     static Object *root;
 
     if (!root) {
-        root = object_new(TYPE_CONTAINER);
+        root = object_root_initialize();
     }
 
     return root;