Add VIFHostDevice support to libvirt driver

This patch adds VIFHostDevice support to the libvirt driver.

* The os-vif VIFHostDevice object describes a PCI passthrough network
  device when dev_type is "ethernet". For an in-depth description, consult:
  https://libvirt.org/formatdomain.html#elementsNICSHostdev

* VIFHostDevice does not specify 802.1Qbh or VLAN options, therefore
  it can be viewed as a simplified "VEB".

* VIFHostDevice with an OVS Representor port profile can be used
  to plug/unplug accelerated OVS ports in future patches.

* TODO: when dev_type is "generic", the object describes a generic
  PCI passthrough device as described in:
  https://libvirt.org/formatdomain.html#elementsHostDevSubsys
  Currently this mode is unimplemented and requires possible changes to
  the XML configuration classes or fundamental os-vif code.

Change-Id: Id7d3964ee632089e7dd2c3fd446a349b1bb9832e
Signed-off-by: Jan Gutter <jan.gutter@netronome.com>

nova/tests/unit/virt/libvirt/test_vif.py

@@ -20,6 +20,7 @@ import mock
 import os_vif
 from os_vif import exception as osv_exception
 from os_vif import objects as osv_objects
+from os_vif.objects import fields as osv_fields
 from oslo_concurrency import processutils
 from oslo_config import cfg
 import six
@@ -398,6 +399,24 @@ class LibvirtVifTestCase(test.NoDBTestCase):
             port_profile=self.os_vif_ovs_prof,
             network=self.os_vif_network)
 
+        self.os_vif_hostdevice_ethernet = osv_objects.vif.VIFHostDevice(
+            id="dc065497-3c8d-4f44-8fb4-e1d33c16a536",
+            address="22:52:25:62:e2:aa",
+            plugin="linux_bridge",
+            vif_name="nicdc065497-3c",
+            dev_type=osv_fields.VIFHostDeviceDevType.ETHERNET,
+            dev_address='0000:0a:00.1',
+            network=self.os_vif_network)
+
+        self.os_vif_hostdevice_generic = osv_objects.vif.VIFHostDevice(
+            id="dc065497-3c8d-4f44-8fb4-e1d33c16a536",
+            address="22:52:25:62:e2:aa",
+            plugin="linux_bridge",
+            vif_name="nicdc065497-3c",
+            dev_type=osv_fields.VIFHostDeviceDevType.GENERIC,
+            dev_address='0000:0a:00.1',
+            network=self.os_vif_network)
+
         self.os_vif_inst_info = osv_objects.instance_info.InstanceInfo(
             uuid="d5b1090c-9e00-4fa4-9504-4b1494857970",
             name="instance-000004da",
@@ -1556,3 +1575,45 @@ class LibvirtVifTestCase(test.NoDBTestCase):
                 <filterref
                  filter="nova-instance-instance-00000001-22522562e2aa"/>
             </interface>""", cfg.to_xml())
+
+    @mock.patch("nova.network.os_vif_util.nova_to_osvif_instance")
+    @mock.patch("nova.network.os_vif_util.nova_to_osvif_vif")
+    def test_config_os_vif_hostdevice_ethernet(self, mock_convert_vif,
+                                               mock_convert_inst):
+        mock_convert_vif.return_value = self.os_vif_hostdevice_ethernet
+        mock_convert_inst.return_value = self.os_vif_inst_info
+
+        hostimpl = host.Host("qemu:///system")
+        flavor = objects.Flavor(name='m1.small')
+        image_meta = objects.ImageMeta.from_dict({})
+        d = vif.LibvirtGenericVIFDriver()
+        cfg = d.get_config(self.instance, self.vif_bridge,
+                           image_meta, flavor,
+                           CONF.libvirt.virt_type,
+                           hostimpl)
+
+        self._assertXmlEqual("""
+            <interface type="hostdev" managed="yes">
+              <mac address="22:52:25:62:e2:aa"/>
+              <source>
+                <address type="pci" domain="0x0000"
+                 bus="0x0a" slot="0x00" function="0x1"/>
+              </source>
+            </interface>""", cfg.to_xml())
+
+    @mock.patch("nova.network.os_vif_util.nova_to_osvif_instance")
+    @mock.patch("nova.network.os_vif_util.nova_to_osvif_vif")
+    def test_config_os_vif_hostdevice_generic(self, mock_convert_vif,
+                                              mock_convert_inst):
+        mock_convert_vif.return_value = self.os_vif_hostdevice_generic
+        mock_convert_inst.return_value = self.os_vif_inst_info
+
+        hostimpl = host.Host("qemu:///system")
+        flavor = objects.Flavor(name='m1.small')
+        image_meta = objects.ImageMeta.from_dict({})
+        d = vif.LibvirtGenericVIFDriver()
+
+        self.assertRaises(exception.InternalError,
+                          d.get_config, self.instance, self.vif_bridge,
+                          image_meta, flavor, CONF.libvirt.virt_type,
+                          hostimpl)

nova/virt/libvirt/vif.py

@@ -23,6 +23,7 @@ import os
 
 import os_vif
 from os_vif import exception as osv_exception
+from os_vif.objects import fields as osv_fields
 from oslo_concurrency import processutils
 from oslo_log import log as logging
 
@@ -468,6 +469,22 @@ class LibvirtGenericVIFDriver(object):
             conf.driver_name = None
             conf.vhost_queues = None
 
+    def _set_config_VIFHostDevice(self, instance, vif, conf, host=None):
+        if vif.dev_type == osv_fields.VIFHostDeviceDevType.ETHERNET:
+            # This sets the required fields for an <interface type='hostdev'>
+            # section in a libvirt domain (by using a subset of hw_veb's
+            # options).
+            designer.set_vif_host_backend_hw_veb(
+                conf, 'hostdev', vif.dev_address, None)
+        else:
+            # TODO(jangutter): dev_type == VIFHostDeviceDevType.GENERIC
+            # is currently unsupported under os-vif. The corresponding conf
+            # class would be: LibvirtConfigGuestHostdevPCI
+            # but os-vif only returns a LibvirtConfigGuestInterface object
+            raise exception.InternalError(
+                _("Unsupported os-vif VIFHostDevice dev_type %(type)s") %
+                {'type': vif.dev_type})
+
     def _set_config_VIFPortProfileOpenVSwitch(self, profile, conf):
         conf.vporttype = "openvswitch"
         conf.add_vport_param("interfaceid",