Add support for vhost-vfio xml gen

- This change introduces xml generation
  support for vhost-vifo interfaces.
- This change support setting the mac
  of vhost-vfio ports
- This change support setting the ring
  layout of vhost-vfio ports. The default
  layout is virtio.

Change-Id: I1f00db50445f4b77cbd0c643cc87562e41ce9840

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

@@ -26,6 +26,84 @@ def assertXmlEqual(self, expectedXmlstr, actualXmlstr):
         self.assertThat(actualXmlstr, matchers.XMLMatches(expectedXmlstr))
 
 
+class LibvirtConfigQemuCommandlineTest(LibvirtConfigBaseTest):
+
+    def test_no_args(self):
+        obj = config.LibvirtConfigQemuCommandline()
+        xml = obj.to_xml()
+
+        self.assertXmlEqual(
+        '<qemu:commandline '
+        'xmlns:qemu="http://libvirt.org/schemas/domain/qemu/1.0"/>', xml)
+
+    def test_with_args(self):
+        obj = config.LibvirtConfigQemuCommandline()
+        obj.args = ['my-first-arg', 'a-second-arg']
+        xml = obj.to_xml()
+
+        self.assertXmlEqual(
+        """<qemu:commandline xmlns:qemu="http://libvirt.org/schemas/domain/qemu/1.0">
+             <qemu:arg value="my-first-arg"/>
+             <qemu:arg value="a-second-arg"/>
+           </qemu:commandline>""", xml)
+
+
+class LibvirtConfigVhostVFIOTest(LibvirtConfigBaseTest):
+
+    def test_default(self):
+        obj = config.LibvirtConfigVhostVFIO()
+        xml = obj.to_xml()
+
+        self.assertXmlEqual(
+        """<qemu:commandline xmlns:qemu="http://libvirt.org/schemas/domain/qemu/1.0">
+             <qemu:arg value="-chardev"/>
+             <qemu:arg value="vfio,id=chardev-,sysfsdev=/sys/bus/mdev/"/>
+             <qemu:arg value="-netdev"/>
+             <qemu:arg value="vhost-vfio,id=netdev-,"""
+        """chardev=chardev-,ringlayout=virtio"/>
+             <qemu:arg value="-device"/>
+             <qemu:arg value="virtio-net-pci,netdev=netdev-,mac="/>
+           </qemu:commandline>""", xml)
+
+    def test_all_params_set(self):
+        obj = config.LibvirtConfigVhostVFIO()
+        obj.uuid = 'fake-uuid'
+        obj.ring_layout = 'fake-layout'
+        obj.path = '/some/fake/path'
+        obj.address = 'fake-mac'
+        xml = obj.to_xml()
+
+        self.assertXmlEqual(
+        """<qemu:commandline xmlns:qemu="http://libvirt.org/schemas/domain/qemu/1.0">
+             <qemu:arg value="-chardev"/>
+             <qemu:arg value="vfio,id=chardev-fake-uui,"""
+        """sysfsdev=/some/fake/path"/>
+             <qemu:arg value="-netdev"/>
+             <qemu:arg value="vhost-vfio,id=netdev-fake-uuid,"""
+        """chardev=chardev-fake-uui,ringlayout=fake-layout"/>
+             <qemu:arg value="-device"/>
+             <qemu:arg value="virtio-net-pci,"""
+        """netdev=netdev-fake-uuid,mac=fake-mac"/>
+           </qemu:commandline>""", xml)
+
+    def test_path_from_uuid(self):
+        obj = config.LibvirtConfigVhostVFIO()
+        obj.uuid = 'fake-uuid'
+        xml = obj.to_xml()
+
+        self.assertXmlEqual(
+        """<qemu:commandline xmlns:qemu="http://libvirt.org/schemas/domain/qemu/1.0">
+             <qemu:arg value="-chardev"/>
+             <qemu:arg value="vfio,id=chardev-fake-uui,"""
+        """sysfsdev=/sys/bus/mdev/fake-uuid"/>
+             <qemu:arg value="-netdev"/>
+             <qemu:arg value="vhost-vfio,id=netdev-fake-uuid,"""
+        """chardev=chardev-fake-uui,ringlayout=virtio"/>
+             <qemu:arg value="-device"/>
+             <qemu:arg value="virtio-net-pci,netdev=netdev-fake-uuid,mac="/>
+           </qemu:commandline>""", xml)
+
+
 class LibvirtConfigTest(LibvirtConfigBaseTest):
 
     def test_config_plain(self):

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

@@ -1721,6 +1721,28 @@ def test_config_os_vif_ovs_hybrid(self, mock_convert_vif,
                  filter="nova-instance-instance-00000001-22522562e2aa"/>
             </interface>""", cfg.to_xml())
 
+    def test_config_vfio(self):
+        driver = vif.LibvirtGenericVIFDriver()
+        vif_details = {"mdev_path": "/fake/mdev/path",
+                       "id": 123, "ring_layout": "fake-layout",
+                       "address": "fake-mac"}
+        conf = driver.get_config_vhostVFIO(None, vif_details, None,
+                                           None, None, None)
+        self.assertEqual(vif_details["mdev_path"], conf.path)
+        self.assertEqual(vif_details["ring_layout"], conf.ring_layout)
+        self.assertEqual(vif_details["id"], conf.uuid)
+        self.assertEqual(vif_details["address"], conf.address)
+
+    def test_config_vfio_no_path_or_layout(self):
+        driver = vif.LibvirtGenericVIFDriver()
+        vif_details = {"id": 123, "address": "fake-mac"}
+        conf = driver.get_config_vhostVFIO(None, vif_details, None,
+                                           None, None, None)
+        self.assertEqual("/sys/bus/mdev/devices/123", conf.path)
+        self.assertEqual("virtio", conf.ring_layout)
+        self.assertEqual(vif_details["id"], conf.uuid)
+        self.assertEqual(vif_details["address"], conf.address)
+
     @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,

nova/virt/libvirt/config.py

@@ -37,6 +37,8 @@
 
 # Namespace to use for Nova specific metadata items in XML
 NOVA_NS = "http://openstack.org/xmlns/libvirt/nova/1.0"
+# Namespace to use for qemu specific items in XML
+QEMU_NS = "http://libvirt.org/schemas/domain/qemu/1.0"
 
 
 class LibvirtConfigObject(object):
@@ -80,6 +82,57 @@ def to_xml(self, pretty_print=True):
         return xml_str
 
 
+class LibvirtConfigQemuCommandline(LibvirtConfigObject):
+
+    def __init__(self, **kwargs):
+        super(LibvirtConfigQemuCommandline, self).__init__(
+            root_name="commandline", ns_prefix="qemu",
+            ns_uri=QEMU_NS, **kwargs)
+        self.args = []
+
+    def format_dom(self):
+        etree.register_namespace('qemu', QEMU_NS)
+        root = super(LibvirtConfigQemuCommandline, self).format_dom()
+        for arg in self.args:
+            elm = etree.SubElement(root, "{%s}arg" % QEMU_NS)
+            elm.set("value", str(arg))
+
+        return root
+
+
+class LibvirtConfigVhostVFIO(LibvirtConfigQemuCommandline):
+
+    def __init__(self, **kwargs):
+        super(LibvirtConfigVhostVFIO, self).__init__(
+             **kwargs)
+        self.uuid = ""
+        self.path = ""
+        self.ring_layout = "virtio"
+        self.address = ""
+
+    def format_dom(self):
+        chardev = ("chardev-%s" % self.uuid)[:16]
+        netdev = ("netdev-%s" % self.uuid)[:16]
+        path = (self.path if self.path
+                else "/sys/bus/mdev/%s" % self.uuid)
+        layout = self.ring_layout
+        self.args = ["-chardev",
+            "vfio,id=%(chardev)s,sysfsdev=%(path)s" % {
+                "chardev": chardev,
+                "path": path},
+            "-netdev",
+            "vhost-vfio,id=%(netdev)s,chardev=%(chardev)s," % {
+                "chardev": chardev,
+                "netdev": netdev,
+            } +
+            "ringlayout=%(layout)s" % {"layout": layout},
+            "-device",
+            "virtio-net-pci,netdev=%(netdev)s,mac=%(mac)s" % {
+                 "netdev": netdev, "mac": self.address}
+            ]
+        return super(LibvirtConfigVhostVFIO, self).format_dom()
+
+
 class LibvirtConfigCaps(LibvirtConfigObject):
 
     def __init__(self, **kwargs):

nova/virt/libvirt/vif.py

@@ -431,6 +431,16 @@ def get_config_vhostuser(self, instance, vif, image_meta,
 
         return conf
 
+    def get_config_vhostVFIO(self, instance, vif, image_meta,
+                            inst_type, virt_type, host):
+        conf = vconfig.LibvirtConfigVhostVFIO()
+        conf.uuid = vif['id']
+        conf.path = vif.get('mdev_path',
+                            "/sys/bus/mdev/devices/%s" % vif['id'])
+        conf.ring_layout = vif.get('ring_layout', 'virtio')
+        conf.address = vif['address']
+        return conf
+
     def get_config_ib_hostdev(self, instance, vif, image_meta,
                               inst_type, virt_type, host):
         return self.get_base_hostdev_pci_config(vif)