Consider hostdev devices when building metadata

Previously, device role tagging metadata would only be built for
LibvirtConfigGuestInterface and LibvirtConfigGuestDisk. This didn't
account for passed through PFs, which can also be tagged and appear as
<hostdev> in the libvirt XML. This caused device role tagging to not
work for PFs. This patch adds support for <hostdev> devices to
_build_device_metadata.

NOTE(artom): Conflicts in nova/tests/unit/virt/libvirt/test_driver.py
due to trusted VFs not being present in Queens.

Change-Id: I24e5ff1b446f2ac41d589c026ce8ee8adad4bcbc
Closes-bug: 1743458
Closes-bug: 1694183
(cherry picked from commit abd01a757b8a83d714a6ab8b5085e7cc1b4a2c5c)

1 files changed, 39 insertions, 0 deletions

diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index 404a096171..907abe7327 100644
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -8675,6 +8675,42 @@ class LibvirtDriver(driver.ComputeDriver):
             device.bus = bus
         return device
 
+    def _build_hostdev_metadata(self, dev, vifs_to_expose, vlans_by_mac):
+        """Builds a metadata object for a hostdev. This can only be a PF, so we
+        don't need trusted_by_mac like in _build_interface_metadata because
+        only VFs can be trusted.
+
+        :param dev: The LibvirtConfigGuestHostdevPCI to build metadata for.
+        :param vifs_to_expose: The list of tagged and/or vlan'ed
+                               VirtualInterface objects.
+        :param vlans_by_mac: A dictionary of mac address -> vlan associations.
+        :return: A NetworkInterfaceMetadata object, or None.
+        """
+        # Strip out the leading '0x'
+        pci_address = pci_utils.get_pci_address(
+            *[x[2:] for x in (dev.domain, dev.bus, dev.slot, dev.function)])
+        try:
+            mac = pci_utils.get_mac_by_pci_address(pci_address,
+                                                   pf_interface=True)
+        except exception.PciDeviceNotFoundById:
+            LOG.debug('Not exposing metadata for not found PCI device %s',
+                      pci_address)
+            return None
+
+        vif = vifs_to_expose.get(mac)
+        if not vif:
+            LOG.debug('No VIF found with MAC %s, not building metadata', mac)
+            return None
+
+        device = objects.NetworkInterfaceMetadata(mac=mac)
+        device.bus = objects.PCIDeviceBus(address=pci_address)
+        if 'tag' in vif and vif.tag:
+            device.tags = [vif.tag]
+        vlan = vlans_by_mac.get(mac)
+        if vlan:
+            device.vlan = int(vlan)
+        return device
+
     def _build_device_metadata(self, context, instance):
         """Builds a metadata object for instance devices, that maps the user
            provided tag to the hypervisor assigned device address.
@@ -8710,6 +8746,9 @@ class LibvirtDriver(driver.ComputeDriver):
                                                         vlans_by_mac)
             if isinstance(dev, vconfig.LibvirtConfigGuestDisk):
                 device = self._build_disk_metadata(dev, tagged_bdms)
+            if isinstance(dev, vconfig.LibvirtConfigGuestHostdevPCI):
+                device = self._build_hostdev_metadata(dev, vifs_to_expose,
+                                                      vlans_by_mac)
             if device:
                 devices.append(device)
         if devices: