Support migrating SRIOV port with bandwidth

For normal ports with resource request it is enough to recalculate the
provider mapping during cold migrations. But for ports with PCI request
(direct, macvtap) the PCI request also needs to be updated to point to
the PF that provides the bandwidth on the destiantion host. So that the
pci claim on the compute allocates the VF from the same PF that provides
the bandwidth resource.

blueprint: support-move-ops-with-qos-ports

Change-Id: I2f3434f06489d8b6cb80933bcb1ea1e841049ba5

Author: Balazs Gibizer

nova/compute/manager.py

@@ -4428,6 +4428,27 @@ def _prep_resize(self, context, image, instance, instance_type,
         instance.system_metadata['old_vm_state'] = vm_state
         instance.save()
 
+        if not isinstance(request_spec, objects.RequestSpec):
+            # Prior to compute RPC API 5.1 conductor would pass a legacy dict
+            # version of the request spec to compute and since Stein compute
+            # could be sending that back to conductor on reschedule, so if we
+            # got a dict convert it to an object.
+            # TODO(mriedem): We can drop this compat code when we only support
+            # compute RPC API >=6.0.
+            request_spec = objects.RequestSpec.from_primitives(
+                context, request_spec, filter_properties)
+            # We don't have to set the new flavor on the request spec because
+            # if we got here it was due to a reschedule from the compute and
+            # the request spec would already have the new flavor in it from the
+            # else block below.
+
+        request_group_resource_providers_mapping = \
+            self._get_request_group_mapping(request_spec)
+
+        if request_group_resource_providers_mapping:
+            self._update_pci_request_spec_with_allocated_interface_name(
+                context, instance, request_group_resource_providers_mapping)
+
         limits = filter_properties.get('limits', {})
         with self.rt.resize_claim(context, instance, instance_type, node,
                                   migration, image_meta=image,
@@ -4505,6 +4526,13 @@ def prep_resize(self, context, image, instance, instance_type,
                                   instance_type, filter_properties,
                                   node, migration, request_spec,
                                   clean_shutdown)
+            except exception.BuildAbortException:
+                # NOTE(gibi): We failed
+                # _update_pci_request_spec_with_allocated_interface_name so
+                # there is no reason to re-schedule. Just revert the allocation
+                # and fail the migration.
+                with excutils.save_and_reraise_exception():
+                    self._revert_allocation(context, instance, migration)
             except Exception:
                 # Since we hit a failure, we're either rescheduling or dead
                 # and either way we need to cleanup any allocations created