machine: add device_type_is_dynamic_sysbus function

Right now the allowance check for adding a sysbus device using
-device cli option (or device_add qmp command) is done well after
the device has been created. It is done during the machine init done
notifier: machine_init_notify() in hw/core/machine.c

This new function will allow us to do the check at the right time and
issue an error if it fails.

Also make device_is_dynamic_sysbus() use the new function.

Signed-off-by: Damien Hedde <damien.hedde@greensocs.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20211029142258.484907-2-damien.hedde@greensocs.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

hw/core/machine.c

@@ -548,18 +548,25 @@ void machine_class_allow_dynamic_sysbus_dev(MachineClass *mc, const char *type)
 
 bool device_is_dynamic_sysbus(MachineClass *mc, DeviceState *dev)
 {
-    bool allowed = false;
-    strList *wl;
     Object *obj = OBJECT(dev);
 
     if (!object_dynamic_cast(obj, TYPE_SYS_BUS_DEVICE)) {
         return false;
     }
 
+    return device_type_is_dynamic_sysbus(mc, object_get_typename(obj));
+}
+
+bool device_type_is_dynamic_sysbus(MachineClass *mc, const char *type)
+{
+    bool allowed = false;
+    strList *wl;
+    ObjectClass *klass = object_class_by_name(type);
+
     for (wl = mc->allowed_dynamic_sysbus_devices;
          !allowed && wl;
          wl = wl->next) {
-        allowed |= !!object_dynamic_cast(obj, wl->value);
+        allowed |= !!object_class_dynamic_cast(klass, wl->value);
     }
 
     return allowed;

include/hw/boards.h

@@ -52,6 +52,21 @@ void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp);
  */
 void machine_class_allow_dynamic_sysbus_dev(MachineClass *mc, const char *type);
 
+/**
+ * device_type_is_dynamic_sysbus: Check if type is an allowed sysbus device
+ * type for the machine class.
+ * @mc: Machine class
+ * @type: type to check (should be a subtype of TYPE_SYS_BUS_DEVICE)
+ *
+ * Returns: true if @type is a type in the machine's list of
+ * dynamically pluggable sysbus devices; otherwise false.
+ *
+ * Check if the QOM type @type is in the list of allowed sysbus device
+ * types (see machine_class_allowed_dynamic_sysbus_dev()).
+ * Note that if @type has a parent type in the list, it is allowed too.
+ */
+bool device_type_is_dynamic_sysbus(MachineClass *mc, const char *type);
+
 /**
  * device_is_dynamic_sysbus: test whether device is a dynamic sysbus device
  * @mc: Machine class