Enable LM back and forth flag for SRIOV

With the inclusion of the Mixed RHEL deployments Live Migration is only
supported from older to new hypervisors. Current SR-IOV live migration
tests migrate back and forth by default. Add the
compute_feature_enabled.live_migrate_back_and_forth to the SR-IOV live
migration tests so that when testing Mixed RHEL deployments tests stop
after initial live migration.

By default the flag is false so adding the configuration as True to
devstack if SR-IOV tests are ever enabled upstream.

Change-Id: I0b188a484dcefd846613d05fe4c49e710778a952

devstack/plugin.sh

@@ -40,6 +40,7 @@ function configure {
     iniset $TEMPEST_CONFIG compute-feature-enabled rbd_download "$COMPUTE_FEATURE_RBD_DOWNLOAD"
     iniset $TEMPEST_CONFIG compute-feature-enabled uefi_secure_boot "$COMPUTE_FEATURE_UEFI_SECURE_BOOT"
     iniset $TEMPEST_CONFIG compute-feature-enabled vtpm_device_supported "$COMPUTE_FEATURE_VTPM_ENABLED"
+    iniset $TEMPEST_CONFIG compute-feature-enabled live_migrate_back_and_forth "$COMPUTE_FEATURE_LIVE_MIGRATE_BACK_AND_FORTH"
 }
 
 if [[ "$1" == "stack" ]]; then

devstack/settings

@@ -24,3 +24,4 @@ COMPUTE_FEATURE_VIRTIO_RNG=${COMPUTE_FEATURE_VIRTIO_RNG:-'True'}
 COMPUTE_FEATURE_RBD_DOWNLOAD=${COMPUTE_FEATURE_RBD_DOWNLOAD:-'False'}
 COMPUTE_FEATURE_UEFI_SECURE_BOOT=${COMPUTE_FEATURE_UEFI_SECURE_BOOT:-'True'}
 COMPUTE_FEATURE_VTPM_ENABLED=${COMPUTE_FEATURE_VTPM_ENABLED:-'True'}
+COMPUTE_FEATURE_LIVE_MIGRATE_BACK_AND_FORTH=${COMPUTE_FEATURE_LIVE_MIGRATE_BACK_AND_FORTH:-'True'}

whitebox_tempest_plugin/api/compute/test_sriov.py

@@ -748,34 +748,38 @@ def _base_test_live_migration(self, vnic_type):
                          'after first migration should be 1 but instead '
                          'is %s' % pci_allocated_count)
 
-        # Migrate server back to the original host
-        self.live_migrate(self.os_admin, server['id'], 'ACTIVE',
-                          target_host=host)
-
-        # Again find the instance's network device element based on the mac
-        # address and binding:vnic_type from the port info provided by ports
-        # client
-        interface_xml_element = self._get_xml_interface_device(
-            server['id'],
-            port['port']['id'],
-        )
+        if CONF.compute_feature_enabled.live_migrate_back_and_forth:
+            # Migrate server back to the original host
+            self.live_migrate(self.os_admin, server['id'], 'ACTIVE',
+                              target_host=host)
+
+            # Again find the instance's network device element based on the
+            # mac address and binding:vnic_type from the port info provided by
+            # ports client
+            interface_xml_element = self._get_xml_interface_device(
+                server['id'],
+                port['port']['id'],
+            )
 
-        # Confirm vlan tag in interface XML, dev_type, allocation status, and
-        # pci address information are correct in pci_devices table of openstack
-        # DB after second migration
-        self._validate_port_xml_vlan_tag(interface_xml_element, self.vlan_id)
-        self._verify_neutron_port_binding(
-            server['id'],
-            port['port']['id']
-        )
+            # Confirm vlan tag in interface XML, dev_type, allocation status,
+            # and pci address information are correct in pci_devices table of
+            # openstack DB after second migration
+            self._validate_port_xml_vlan_tag(
+                interface_xml_element,
+                self.vlan_id
+            )
+            self._verify_neutron_port_binding(
+                server['id'],
+                port['port']['id']
+            )
 
-        # Confirm total port allocations still remains one after final
-        # migration
-        pci_allocated_count = self._get_pci_status_count(
-            pci_device_status_regex)
-        self.assertEqual(pci_allocated_count, 1, 'Total allocated pci devices '
-                         'after second migration should be 1 but instead '
-                         'is %s' % pci_allocated_count)
+            # Confirm total port allocations still remains one after final
+            # migration
+            pci_allocated_count = self._get_pci_status_count(
+                pci_device_status_regex)
+            self.assertEqual(pci_allocated_count, 1, 'Total allocated pci '
+                             'devices after second migration should be 1 but '
+                             'instead is %s' % pci_allocated_count)
 
     def test_sriov_direct_live_migration(self):
         """Verify sriov live migration using direct type ports
@@ -798,7 +802,7 @@ def setUp(self):
         self.network = self._create_net_from_physical_network(
             self.vlan_id,
             self.physical_net)
-        self._create_subnet(self.sriov_network['network']['id'])
+        self._create_subnet(self.network['network']['id'])
 
     @classmethod
     def skip_checks(cls):
@@ -900,7 +904,7 @@ def _validate_port_data_after_attach(self, pre_attached_port,
         attached port
         :param after_attached: dict, original port data when first created
         """
-        net_id = self.sriov_network.get('network').get('id')
+        net_id = self.network.get('network').get('id')
         port_id = pre_attached_port['port']['id']
         port_ip_addr = pre_attached_port['port']['fixed_ips'][0]['ip_address']
         port_mac_addr = pre_attached_port['port']['mac_address']
@@ -941,7 +945,7 @@ def _base_test_attach_and_detach_sriov_port(self, vnic_type):
         servers = [self.create_server_and_ssh(),
                    self.create_server_and_ssh()]
         port = self._create_port_from_vnic_type(
-            net=self.sriov_network,
+            net=self.network,
             vnic_type=vnic_type
         )
 
@@ -1024,7 +1028,7 @@ def test_sriov_direct_physical_attach_detach_port(self):
         servers = [self.create_server_and_ssh(),
                    self.create_server_and_ssh()]
         port = self._create_port_from_vnic_type(
-            net=self.sriov_network,
+            net=self.network,
             vnic_type='direct-physical'
         )