fix sriov-vf release mac reset

this commit fix a mac reset issue when the sriov-cni failed to
configure the original mac address on vf release function on some
of them vendor nics

Signed-off-by: Sebastian Sch <sebassch@gmail.com>

pkg/sriov/sriov.go

@@ -176,7 +176,27 @@ func (s *sriovManager) ReleaseVF(conf *sriovtypes.NetConf, podifName string, cid
 				return fmt.Errorf("failed to parse original effective MAC address %s: %v", conf.OrigVfState.EffectiveMAC, err)
 			}
 
-			if err = s.nLink.LinkSetHardwareAddr(linkObj, hwaddr); err != nil {
+			/* Some NIC drivers (i.e. i40e/iavf) set VF MAC address asynchronously.
+			   This means that we can get an error from the setHardwareAddr, or it may just fail silently
+			   so to cover both cases we will retry the set function
+			   and also check the mac address on the VF after the configuration.
+			*/
+			err = utils.Retry(10, 100*time.Millisecond, func() error {
+				if err := s.nLink.LinkSetHardwareAddr(linkObj, hwaddr); err != nil {
+					return err
+				}
+
+				linkObj, err = s.nLink.LinkByName(conf.OrigVfState.HostIFName)
+				if err != nil {
+					return fmt.Errorf("failed to get netlink device with name %s: %q", linkObj.Attrs().Name, err)
+				}
+				if linkObj.Attrs().HardwareAddr.String() != conf.OrigVfState.EffectiveMAC {
+					return fmt.Errorf("effective nic mac address is different from original one")
+				}
+
+				return nil
+			})
+			if err != nil {
 				return fmt.Errorf("failed to restore original effective netlink MAC address %s: %v", hwaddr, err)
 			}
 		}

pkg/sriov/sriov_test.go

@@ -208,9 +208,12 @@ var _ = Describe("Sriov", func() {
 			}()
 			Expect(err).NotTo(HaveOccurred())
 			mocked := &mocks_utils.NetlinkManager{}
-			fakeLink := &FakeLink{netlink.LinkAttrs{Index: 1000, Name: "dummylink"}}
+			macaddr, err := net.ParseMAC("c6:c8:7f:1f:21:90")
+			Expect(err).NotTo(HaveOccurred())
+			fakeLink := &FakeLink{netlink.LinkAttrs{Index: 1000, Name: "dummylink", HardwareAddr: macaddr}}
 
 			mocked.On("LinkByName", netconf.ContIFNames).Return(fakeLink, nil)
+			mocked.On("LinkByName", netconf.OrigVfState.HostIFName).Return(fakeLink, nil)
 			mocked.On("LinkSetDown", fakeLink).Return(nil)
 			mocked.On("LinkSetName", fakeLink, netconf.OrigVfState.HostIFName).Return(nil)
 			mocked.On("LinkSetNsFd", fakeLink, mock.AnythingOfType("int")).Return(nil)