Merge "Support Cpu Compararion on Aarch64 Platform"

Author: Zuul

nova/tests/unit/virt/libvirt/test_driver.py

@@ -10978,22 +10978,49 @@ def test_compare_cpu_handles_not_supported_error_gracefully(self,
                 instance)
         self.assertIsNone(ret)
 
-    @mock.patch.object(host.Host, 'compare_cpu')
+    @mock.patch.object(fakelibvirt.Connection, 'getLibVersion',
+                       return_value=versionutils.convert_version_to_int(
+                           libvirt_driver.MIN_LIBVIRT_AARCH64_CPU_COMPARE) - 1
+                       )
     @mock.patch.object(nova.virt.libvirt, 'config')
     def test_compare_cpu_aarch64_skip_comparison(self,
                                                  mock_vconfig,
-                                                 mock_compare):
+                                                 mock_get_libversion):
         instance = objects.Instance(**self.test_instance)
-        skip_comparison_exc = fakelibvirt.make_libvirtError(
-                fakelibvirt.libvirtError,
-                'Host CPU compatibility check does not make '
-                'sense on AArch64; skip CPU comparison')
-        mock_compare.side_effect = skip_comparison_exc
+        self.mock_uname.return_value = fakelibvirt.os_uname(
+            'Linux', '', '5.4.0-0-generic', '', fields.Architecture.AARCH64)
         conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         ret = conn._compare_cpu(None, jsonutils.dumps(_fake_cpu_info_aarch64),
                 instance)
         self.assertIsNone(ret)
 
+    @mock.patch.object(host.Host, 'get_capabilities')
+    @mock.patch.object(fakelibvirt.Connection, 'getLibVersion',
+                       return_value=versionutils.convert_version_to_int(
+                           libvirt_driver.MIN_LIBVIRT_AARCH64_CPU_COMPARE))
+    @mock.patch.object(host.Host, 'compare_cpu')
+    def test_compare_cpu_host_aarch64(self,
+                                      mock_compare,
+                                      mock_get_libversion,
+                                      mock_caps):
+        instance = objects.Instance(**self.test_instance)
+        mock_compare.return_value = 6
+        caps = vconfig.LibvirtConfigCaps()
+        caps.host = vconfig.LibvirtConfigCapsHost()
+        caps.host.cpu = vconfig.LibvirtConfigCPU()
+        caps.host.cpu.arch = fields.Architecture.AARCH64
+        caps.host.topology = fakelibvirt.NUMATopology()
+
+        mock_caps.return_value = caps
+        self.mock_uname.return_value = fakelibvirt.os_uname(
+            'Linux', '', '5.4.0-0-generic', '', fields.Architecture.AARCH64)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
+        ret = conn._compare_cpu(None,
+                                jsonutils.dumps(_fake_cpu_info_aarch64),
+                                instance)
+        mock_compare.assert_called_once_with(caps.host.cpu.to_xml())
+        self.assertIsNone(ret)
+
     @mock.patch.object(host.Host, 'compare_cpu')
     @mock.patch.object(nova.virt.libvirt.LibvirtDriver,
                        '_vcpu_model_to_cpu_config')

nova/tests/unit/virt/libvirt/test_host.py

@@ -689,6 +689,23 @@ def test_get_capabilities_no_host_cpu_model(self):
             self.assertIsNone(caps.host.cpu.model)
             self.assertEqual(0, len(caps.host.cpu.features))
 
+    def test_get_capabilities_on_aarch64(self):
+        """Tests that cpu features are not retrieved on aarch64 platform.
+        """
+        fake_caps_xml = '''
+<capabilities>
+  <host>
+    <uuid>cef19ce0-0ca2-11df-855d-b193fbce7686</uuid>
+    <cpu>
+      <arch>aarch64</arch>
+    </cpu>
+  </host>
+</capabilities>'''
+        with mock.patch.object(fakelibvirt.virConnect, 'getCapabilities',
+                               return_value=fake_caps_xml):
+            caps = self.host.get_capabilities()
+            self.assertEqual(0, len(caps.host.cpu.features))
+
     def test__get_machine_types(self):
         expected = [
             # NOTE(aspiers): in the real world, i686 would probably

nova/virt/libvirt/driver.py

@@ -219,6 +219,8 @@ def repr_method(self):
 NEXT_MIN_LIBVIRT_VERSION = (7, 0, 0)
 NEXT_MIN_QEMU_VERSION = (5, 2, 0)
 
+MIN_LIBVIRT_AARCH64_CPU_COMPARE = (6, 9, 0)
+
 # Virtuozzo driver support
 MIN_VIRTUOZZO_VERSION = (7, 0, 0)
 
@@ -9394,6 +9396,20 @@ def _compare_cpu(self, guest_cpu, host_cpu_str, instance):
         else:
             cpu = self._vcpu_model_to_cpu_config(guest_cpu)
 
+        host_cpu = self._host.get_capabilities().host.cpu
+        if host_cpu.arch == fields.Architecture.AARCH64:
+            if self._host.has_min_version(MIN_LIBVIRT_AARCH64_CPU_COMPARE):
+                LOG.debug("On AArch64 hosts, source and destination host "
+                          "CPUs are compared to check if they're compatible"
+                          "(the only use-case supported by libvirt for "
+                          "Arm64/AArch64)")
+                cpu = host_cpu
+            else:
+                LOG.debug("You need %s libvirt version to be able to compare "
+                          "source host CPU with destination host CPU; skip "
+                          "CPU comparison", MIN_LIBVIRT_AARCH64_CPU_COMPARE)
+                return
+
         u = ("http://libvirt.org/html/libvirt-libvirt-host.html#"
              "virCPUCompareResult")
         m = _("CPU doesn't have compatibility.\n\n%(ret)s\n\nRefer to %(u)s")
@@ -9403,10 +9419,6 @@ def _compare_cpu(self, guest_cpu, host_cpu_str, instance):
             LOG.debug("cpu compare xml: %s", cpu_xml, instance=instance)
             ret = self._host.compare_cpu(cpu_xml)
         except libvirt.libvirtError as e:
-            if cpu.arch == fields.Architecture.AARCH64:
-                LOG.debug("Host CPU compatibility check does not make "
-                          "sense on AArch64; skip CPU comparison")
-                return
             error_code = e.get_error_code()
             if error_code == libvirt.VIR_ERR_NO_SUPPORT:
                 LOG.debug("URI %(uri)s does not support cpu comparison. "

nova/virt/libvirt/host.py

@@ -793,13 +793,17 @@ def get_capabilities(self):
                 xml_str = self._caps.host.cpu.to_xml()
                 if isinstance(xml_str, bytes):
                     xml_str = xml_str.decode('utf-8')
-                features = self.get_connection().baselineCPU(
-                    [xml_str],
-                    libvirt.VIR_CONNECT_BASELINE_CPU_EXPAND_FEATURES)
-                if features:
-                    cpu = vconfig.LibvirtConfigCPU()
-                    cpu.parse_str(features)
-                    self._caps.host.cpu.features = cpu.features
+                # NOTE(kevinz): The baseline CPU info on Aarch64 will not
+                # include any features. So on Aarch64, we use the original
+                # features from LibvirtConfigCaps.
+                if self._caps.host.cpu.arch != fields.Architecture.AARCH64:
+                    features = self.get_connection().baselineCPU(
+                        [xml_str],
+                        libvirt.VIR_CONNECT_BASELINE_CPU_EXPAND_FEATURES)
+                    if features:
+                        cpu = vconfig.LibvirtConfigCPU()
+                        cpu.parse_str(features)
+                        self._caps.host.cpu.features = cpu.features
             except libvirt.libvirtError as ex:
                 error_code = ex.get_error_code()
                 if error_code == libvirt.VIR_ERR_NO_SUPPORT: