Merge "Allow tap interface with multiqueue" into stable/stein

3 files changed, 111 insertions, 18 deletions

diff --git a/nova/tests/unit/virt/libvirt/test_vif.py b/nova/tests/unit/virt/libvirt/test_vif.py
index 4d4168bcc7..504216ed03 100644
--- a/nova/tests/unit/virt/libvirt/test_vif.py
+++ b/nova/tests/unit/virt/libvirt/test_vif.py
@@ -1125,10 +1125,71 @@ class LibvirtVifTestCase(test.NoDBTestCase):
     @mock.patch('nova.privsep.linux_net.device_exists', return_value=True)
     @mock.patch('nova.privsep.linux_net.set_device_mtu')
     @mock.patch('nova.privsep.linux_net.create_tap_dev')
-    def test_plug_tap(self, mock_create_tap_dev, mock_set_mtu,
+    def test_plug_tap_kvm_virtio(self, mock_create_tap_dev, mock_set_mtu,
                       mock_device_exists):
-        d = vif.LibvirtGenericVIFDriver()
-        d.plug(self.instance, self.vif_tap)
+
+        d1 = vif.LibvirtGenericVIFDriver()
+        ins = objects.Instance(
+            id=1, uuid='f0000000-0000-0000-0000-000000000001',
+            project_id=723, system_metadata={}
+        )
+        d1.plug(ins, self.vif_tap)
+        mock_create_tap_dev.assert_called_once_with('tap-xxx-yyy-zzz', None,
+                                                    multiqueue=False)
+
+        mock_create_tap_dev.reset_mock()
+
+        d2 = vif.LibvirtGenericVIFDriver()
+        mq_ins = objects.Instance(
+            id=1, uuid='f0000000-0000-0000-0000-000000000001',
+            project_id=723, system_metadata={
+                'image_hw_vif_multiqueue_enabled': 'True'
+            }
+        )
+        d2.plug(mq_ins, self.vif_tap)
+        mock_create_tap_dev.assert_called_once_with('tap-xxx-yyy-zzz', None,
+                                                    multiqueue=True)
+
+    @mock.patch('nova.privsep.linux_net.device_exists', return_value=True)
+    @mock.patch('nova.privsep.linux_net.set_device_mtu')
+    @mock.patch('nova.privsep.linux_net.create_tap_dev')
+    def test_plug_tap_mq_ignored_virt_type(
+            self, mock_create_tap_dev, mock_set_mtu, mock_device_exists):
+
+        self.flags(use_virtio_for_bridges=True,
+                   virt_type='xen',
+                   group='libvirt')
+
+        d1 = vif.LibvirtGenericVIFDriver()
+        ins = objects.Instance(
+            id=1, uuid='f0000000-0000-0000-0000-000000000001',
+            project_id=723, system_metadata={
+                'image_hw_vif_multiqueue_enabled': 'True'
+            }
+        )
+        d1.plug(ins, self.vif_tap)
+        mock_create_tap_dev.assert_called_once_with('tap-xxx-yyy-zzz',
+                                                    None,
+                                                    multiqueue=False)
+
+    @mock.patch('nova.privsep.linux_net.device_exists', return_value=True)
+    @mock.patch('nova.privsep.linux_net.set_device_mtu')
+    @mock.patch('nova.privsep.linux_net.create_tap_dev')
+    def test_plug_tap_mq_ignored_vif_model(
+            self, mock_create_tap_dev, mock_set_mtu, mock_device_exists):
+
+        d1 = vif.LibvirtGenericVIFDriver()
+        ins = objects.Instance(
+            id=1, uuid='f0000000-0000-0000-0000-000000000001',
+            project_id=723, system_metadata={
+                'image_hw_vif_multiqueue_enabled': 'True',
+                'image_hw_vif_model': 'e1000',
+            }
+        )
+        d1.plug(ins, self.vif_tap)
+        mock_create_tap_dev.assert_called_once_with('tap-xxx-yyy-zzz',
+                                                    None,
+                                                    multiqueue=False)
 
     def test_unplug_tap(self):
         d = vif.LibvirtGenericVIFDriver()
diff --git a/nova/virt/libvirt/vif.py b/nova/virt/libvirt/vif.py
index 57ea1a7382..91e0f4591f 100644
--- a/nova/virt/libvirt/vif.py
+++ b/nova/virt/libvirt/vif.py
@@ -136,6 +136,24 @@ class LibvirtGenericVIFDriver(object):
         devname = self.get_vif_devname(vif)
         return prefix + devname[3:]
 
+    def get_vif_model(self, image_meta=None, vif_model=None):
+
+        model = vif_model
+
+        # If the user has specified a 'vif_model' against the
+        # image then honour that model
+        if image_meta:
+            model = osinfo.HardwareProperties(image_meta).network_model
+
+        # If the virt type is KVM/QEMU/VZ(Parallels), then use virtio according
+        # to the global config parameter
+        if (model is None and CONF.libvirt.virt_type in
+                ('kvm', 'qemu', 'parallels') and
+                CONF.libvirt.use_virtio_for_bridges):
+            model = network_model.VIF_MODEL_VIRTIO
+
+        return model
+
     def get_base_config(self, instance, mac, image_meta,
                         inst_type, virt_type, vnic_type, host):
         # TODO(sahid): We should rewrite it. This method handles too
@@ -156,16 +174,9 @@ class LibvirtGenericVIFDriver(object):
                 conf, mac, model, driver, vhost_queues, rx_queue_size)
             return conf
 
-        # If the user has specified a 'vif_model' against the
-        # image then honour that model
-        if image_meta:
-            model = osinfo.HardwareProperties(image_meta).network_model
-
-        # If the virt type is KVM/QEMU/VZ(Parallels), then use virtio according
-        # to the global config parameter
-        if (model is None and virt_type in ('kvm', 'qemu', 'parallels') and
-                CONF.libvirt.use_virtio_for_bridges):
-            model = network_model.VIF_MODEL_VIRTIO
+        # if model has already been defined,
+        # image_meta contents will override it
+        model = self.get_vif_model(image_meta=image_meta, vif_model=model)
 
         # Workaround libvirt bug, where it mistakenly
         # enables vhost mode, even for non-KVM guests
@@ -221,10 +232,7 @@ class LibvirtGenericVIFDriver(object):
         """
         driver = None
         vhost_queues = None
-        if not isinstance(image_meta, objects.ImageMeta):
-            image_meta = objects.ImageMeta.from_dict(image_meta)
-        img_props = image_meta.properties
-        if img_props.get('hw_vif_multiqueue_enabled'):
+        if self._requests_multiqueue(image_meta):
             driver = 'vhost'
             max_tap_queues = self._get_max_tap_queues()
             if max_tap_queues:
@@ -235,6 +243,19 @@ class LibvirtGenericVIFDriver(object):
 
         return (driver, vhost_queues)
 
+    def _requests_multiqueue(self, image_meta):
+        """Check if multiqueue property is set in the image metadata."""
+
+        if not isinstance(image_meta, objects.ImageMeta):
+            image_meta = objects.ImageMeta.from_dict(image_meta)
+
+        img_props = image_meta.properties
+
+        if img_props.get('hw_vif_multiqueue_enabled'):
+            return True
+
+        return False
+
     def _get_max_tap_queues(self):
         # NOTE(kengo.sakai): In kernels prior to 3.0,
         # multiple queues on a tap interface is not supported.
@@ -697,7 +718,13 @@ class LibvirtGenericVIFDriver(object):
         """Plug a VIF_TYPE_TAP virtual interface."""
         dev = self.get_vif_devname(vif)
         mac = vif['details'].get(network_model.VIF_DETAILS_TAP_MAC_ADDRESS)
-        nova.privsep.linux_net.create_tap_dev(dev, mac)
+        image_meta = instance.image_meta
+        vif_model = self.get_vif_model(image_meta=image_meta)
+        # TODO(ganso): explore whether multiqueue works for other vif models
+        # that go through this code path.
+        multiqueue = (self._requests_multiqueue(image_meta) and
+                      vif_model == network_model.VIF_MODEL_VIRTIO)
+        nova.privsep.linux_net.create_tap_dev(dev, mac, multiqueue=multiqueue)
         network = vif.get('network')
         mtu = network.get_meta('mtu') if network else None
         nova.privsep.linux_net.set_device_mtu(dev, mtu)
diff --git a/releasenotes/notes/bug-1893263-769acadc4b6141d0.yaml b/releasenotes/notes/bug-1893263-769acadc4b6141d0.yaml
new file mode 100644
index 0000000000..3874489513
--- /dev/null
+++ b/releasenotes/notes/bug-1893263-769acadc4b6141d0.yaml
@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Addressed an issue that prevented instances using multiqueue feature from
+    being created successfully when their vif_type is TAP.