diff --git a/nova/tests/unit/virt/xenapi/test_xenapi.py b/nova/tests/unit/virt/xenapi/test_xenapi.py
index 28b50ac5ea..936356206e 100644
--- a/nova/tests/unit/virt/xenapi/test_xenapi.py
+++ b/nova/tests/unit/virt/xenapi/test_xenapi.py
@@ -453,7 +453,7 @@ class XenAPIVMTestCase(stubs.XenAPITestBase):
                               'write_requests': 0}],
             'memory_details': {'maximum': 8192, 'used': 0}}
 
-        instance = self._create_instance()
+        instance = self._create_instance(obj=True)
         actual = self.conn.get_instance_diagnostics(instance)
         self.assertEqual(expected, actual.serialize())
 
diff --git a/nova/virt/configdrive.py b/nova/virt/configdrive.py
index ed32b087ed..e735421261 100644
--- a/nova/virt/configdrive.py
+++ b/nova/virt/configdrive.py
@@ -185,7 +185,7 @@ def required_by(instance):
         "img_config_drive",
         fields.ConfigDrivePolicy.OPTIONAL)
 
-    return (instance.get('config_drive') or
+    return (instance.config_drive or
             'always' == CONF.force_config_drive or
             strutils.bool_from_string(CONF.force_config_drive) or
             image_prop == fields.ConfigDrivePolicy.MANDATORY