From 5f5590f7f4c90fcd1869dadc6ec7e5ea5ab6979e Mon Sep 17 00:00:00 2001
From: Vladik Romanovsky <vladik.romanovsky@enovance.com>
Date: Fri, 23 Jan 2015 07:30:41 -0500
Subject: [PATCH] libvirt: use osinfo when configuring the disk bus

Start using libosinfo in the blockinfo module, when configuring the
disk bus.

Partially implements blueprint libvirt-hardware-policy-from-libosinfo

Change-Id: I7a9669070a0eca04b97104aec92609fbf631ffc8
---
 nova/tests/unit/virt/libvirt/test_blockinfo.py | 13 +++++++++++++
 nova/virt/libvirt/blockinfo.py                 |  8 ++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/nova/tests/unit/virt/libvirt/test_blockinfo.py b/nova/tests/unit/virt/libvirt/test_blockinfo.py
index a1450b325ef6..146caabb16fe 100644
--- a/nova/tests/unit/virt/libvirt/test_blockinfo.py
+++ b/nova/tests/unit/virt/libvirt/test_blockinfo.py
@@ -15,6 +15,7 @@
 
 import copy
 
+import fixtures
 import mock
 
 from nova import block_device
@@ -25,6 +26,7 @@ from nova import objects
 from nova import test
 from nova.tests.unit import fake_block_device
 import nova.tests.unit.image.fake
+from nova.tests.unit.virt import fakelibosinfo
 from nova.virt import block_device as driver_block_device
 from nova.virt import driver
 from nova.virt.libvirt import blockinfo
@@ -744,6 +746,17 @@ class LibvirtBlockInfoTest(test.NoDBTestCase):
                           blockinfo.get_disk_bus_for_device_type,
                           instance, 'kvm', image_meta)
 
+    def test_get_disk_bus_with_osinfo(self):
+        self.useFixture(fixtures.MonkeyPatch(
+            'nova.virt.osinfo.libosinfo',
+            fakelibosinfo))
+        instance = objects.Instance(**self.test_instance)
+        image_meta = {'properties': {'os_name': 'fedora22'}}
+        image_meta = objects.ImageMeta.from_dict(image_meta)
+        bus = blockinfo.get_disk_bus_for_device_type(instance,
+                                                     'kvm', image_meta)
+        self.assertEqual('virtio', bus)
+
     def test_success_get_disk_bus_for_disk_dev(self):
         expected = (
                 ('ide', ("kvm", "hda")),
diff --git a/nova/virt/libvirt/blockinfo.py b/nova/virt/libvirt/blockinfo.py
index 5cc411cd0046..f770bbc784a3 100644
--- a/nova/virt/libvirt/blockinfo.py
+++ b/nova/virt/libvirt/blockinfo.py
@@ -84,6 +84,7 @@ from nova.objects import base as obj_base
 from nova.virt import configdrive
 from nova.virt import driver
 from nova.virt.libvirt import utils as libvirt_utils
+from nova.virt import osinfo
 
 CONF = cfg.CONF
 
@@ -234,8 +235,11 @@ def get_disk_bus_for_device_type(instance,
     """
 
     # Prefer a disk bus set against the image first of all
-    key = "hw_" + device_type + "_bus"
-    disk_bus = image_meta.properties.get(key)
+    if device_type == "disk":
+        disk_bus = osinfo.HardwareProperties(image_meta).disk_model
+    else:
+        key = "hw_" + device_type + "_bus"
+        disk_bus = image_meta.properties.get(key)
     if disk_bus is not None:
         if not is_disk_bus_valid_for_virt(virt_type, disk_bus):
             raise exception.UnsupportedHardware(model=disk_bus,