Power on cores for isolated emulator threads

Previously, with the `isolate` emulator threads policy and libvirt cpu
power management enabled, we did not power on the cores to which the
emulator threads were pin. Start doing that, and don't forget to power
them down when the instance is stopped.

Closes-bug: 2056612
Change-Id: I6e5383d8a0bf3f0ed8c870754cddae4e9163b4fd
(cherry picked from commit 0986d2b)
(cherry picked from commit 4bcf5ad)

Author: notartom

nova/tests/functional/libvirt/test_power_manage.py

@@ -147,7 +147,26 @@ def test_create_server_with_emulator_threads_isolate(self):
         self.assertTrue(
             numa_topology.cpu_pinning.isdisjoint(
                 numa_topology.cpuset_reserved))
-        # FIXME(artom) We've not actually powered on the emulator threads core
+        self._assert_cpu_set_state(numa_topology.cpuset_reserved,
+                                   expected='online')
+
+    def test_start_stop_server_with_emulator_threads_isolate(self):
+        server = self._create_server(
+            flavor_id=self.isolate_flavor_id,
+            expected_state='ACTIVE')
+        # Let's verify that the pinned CPUs are now online
+        self._assert_server_cpus_state(server, expected='online')
+        instance = objects.Instance.get_by_uuid(self.ctxt, server['id'])
+        numa_topology = instance.numa_topology
+        # Make sure we've pinned the emulator threads to a separate core
+        self.assertTrue(numa_topology.cpuset_reserved)
+        self.assertTrue(
+            numa_topology.cpu_pinning.isdisjoint(
+                numa_topology.cpuset_reserved))
+        self._assert_cpu_set_state(numa_topology.cpuset_reserved,
+                                   expected='online')
+        # Stop and assert we've powered down the emulator threads core as well
+        server = self._stop_server(server)
         self._assert_cpu_set_state(numa_topology.cpuset_reserved,
                                    expected='offline')
 

nova/virt/libvirt/cpu/api.py

@@ -82,7 +82,8 @@ def power_up(instance: objects.Instance) -> None:
         return
 
     cpu_dedicated_set = hardware.get_cpu_dedicated_set_nozero() or set()
-    pcpus = instance.numa_topology.cpu_pinning
+    pcpus = instance.numa_topology.cpu_pinning.union(
+        instance.numa_topology.cpuset_reserved)
     powered_up = set()
     for pcpu in pcpus:
         if pcpu in cpu_dedicated_set:
@@ -102,7 +103,8 @@ def power_down(instance: objects.Instance) -> None:
         return
 
     cpu_dedicated_set = hardware.get_cpu_dedicated_set_nozero() or set()
-    pcpus = instance.numa_topology.cpu_pinning
+    pcpus = instance.numa_topology.cpu_pinning.union(
+        instance.numa_topology.cpuset_reserved)
     powered_down = set()
     for pcpu in pcpus:
         if pcpu in cpu_dedicated_set: