Read NIC features in libvirt

Reads the NIC feature information from the 'net' devices
given by 'libvirt'. This information is added to
pci_devices.extra_info dictionary under a dictionary
labeled 'capabilities'; this dictionary will contain a key
labeled 'network' with the list of capabilities. E.g.:

  extra_info: {'capabilities':
                {'network': ['gso', 'sg', 'tso', 'tx']}
              }

'libvirt' implemented the NIC feature discovery in version
1.2.14 (https://libvirt.org/news-2015.html)

blueprint enable-sriov-nic-features

Change-Id: Ia5b6abbbf4e5f762e0df04167c32c6135781d305

1 files changed, 24 insertions, 0 deletions

diff --git a/nova/pci/utils.py b/nova/pci/utils.py
index c68eaf7dea..489853e2c3 100644
--- a/nova/pci/utils.py
+++ b/nova/pci/utils.py
@@ -171,3 +171,27 @@ def get_vf_num_by_pci_address(pci_addr):
     if vf_num is None:
         raise exception.PciDeviceNotFoundById(id=pci_addr)
     return vf_num
+
+
+def get_net_name_by_vf_pci_address(vfaddress):
+    """Given the VF PCI address, returns the net device name.
+
+    Every VF is associated to a PCI network device. This function
+    returns the libvirt name given to this network device; e.g.:
+
+        <device>
+            <name>net_enp8s0f0_90_e2_ba_5e_a6_40</name>
+        ...
+
+    In the libvirt parser information tree, the network device stores the
+    network capabilities associated to this device.
+    """
+    try:
+        mac = get_mac_by_pci_address(vfaddress).split(':')
+        ifname = get_ifname_by_pci_address(vfaddress)
+        return ("net_%(ifname)s_%(mac)s" %
+                {'ifname': ifname, 'mac': '_'.join(mac)})
+    except Exception:
+        LOG.warning("No net device was found for VF %(vfaddress)s",
+                    {'vfaddress': vfaddress})
+        return