add metadef vlaues for new video models

- This change adds the newly supported libvirt
  video models, virtio, gop and none.
- This change updates the train metadefs changes
  release note.

Change-Id: I440a038b53825b5f92fc977566edcf3cabfba673

doc/source/admin/useful-image-properties.rst

@@ -408,8 +408,10 @@ Here is a list of useful image properties and the values they expect.
      - Integer
    * - libvirt API driver
      - ``hw_video_model``
-     - The video image driver used.
-     - ``vga``, ``cirrus``, ``vmvga``, ``xen``, or ``qxl``.
+     - The graphic device model presented to the guest.
+       hw_video_model=none disables the graphics device in the guest and should
+       generally be used when using gpu passthrough.
+     - ``vga``, ``cirrus``, ``vmvga``, ``xen``, ``qxl``, ``virtio``, ``gop`` or ``none``.
    * - libvirt API driver
      - ``hw_video_ram``
      - Maximum RAM for the video image. Used only if a ``hw_video:ram_max_mb``

etc/metadefs/compute-libvirt-image.json

@@ -44,14 +44,17 @@
         },
         "hw_video_model": {
             "title": "Video Model",
-            "description": "The video image driver used.",
+            "description": "The graphic device model presented to the guest. hw_video_model=none disables the graphics device in the guest and should generally be used when using gpu passthrough.",
             "type": "string",
             "enum": [
                 "vga",
                 "cirrus",
                 "vmvga",
                 "xen",
-                "qxl"
+                "qxl",
+                "virtio",
+                "gop",
+                "none"
             ]
         },
         "hw_video_ram": {

releasenotes/notes/train-metadefs-changes-c4380754cdd13a19.yaml

@@ -7,6 +7,9 @@ upgrade:
     * Added ``powervm`` to the ``hypervisor_type`` enumeration in the
       ``OS:::Compute::Hypervisor`` namespace.
 
+    * Added ``virtio``, ``gop`` and ``none`` to the ``hw_video_model``
+      enumeration in the ``OS::Compute::LibvirtImage`` namespace.
+
     You may upgrade these definitions using:
 
     ``glance-manage db load_metadefs [--path <path>] [--merge] [--prefer_new]``