Merge "libvirt: Start reporting 'HW_CPU_HYPERTHREADING' trait"

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

@@ -22918,11 +22918,21 @@ class LibvirtDriverTestCase(test.NoDBTestCase, TraitsComparisonMixin):
 
     @mock.patch.object(libvirt_driver.LibvirtDriver, '_get_cpu_feature_traits',
                        new=mock.Mock(return_value={}))
-    def test_cpu_traits_sev_no_feature_traits(self):
+    def test_cpu_traits__sev_support(self):
         for support in (False, True):
             self.drvr._host._supports_amd_sev = support
-            self.assertEqual({ot.HW_CPU_X86_AMD_SEV: support},
-                             self.drvr._get_cpu_traits())
+            traits = self.drvr._get_cpu_traits()
+            self.assertIn(ot.HW_CPU_X86_AMD_SEV, traits)
+            self.assertEqual(support, traits[ot.HW_CPU_X86_AMD_SEV])
+
+    @mock.patch.object(libvirt_driver.LibvirtDriver, '_get_cpu_feature_traits',
+                       new=mock.Mock(return_value={}))
+    def test_cpu_traits__hyperthreading_support(self):
+        for support in (False, True):
+            self.drvr._host._has_hyperthreading = support
+            traits = self.drvr._get_cpu_traits()
+            self.assertIn(ot.HW_CPU_HYPERTHREADING, traits)
+            self.assertEqual(support, traits[ot.HW_CPU_HYPERTHREADING])
 
     def test_cpu_traits_with_passthrough_mode(self):
         """Test getting CPU traits when cpu_mmode is 'host-passthrough', traits

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

@@ -1166,6 +1166,56 @@ cg /cgroup/memory cg opt1,opt2 0 0
     def test_is_cpu_control_policy_capable_ioerror(self, mock_open):
         self.assertFalse(self.host.is_cpu_control_policy_capable())
 
+    @mock.patch('nova.virt.libvirt.host.libvirt.Connection.getCapabilities')
+    def test_has_hyperthreading__true(self, mock_cap):
+        mock_cap.return_value = """
+        <capabilities>
+          <host>
+            <uuid>1f71d34a-7c89-45cf-95ce-3df20fc6b936</uuid>
+            <cpu>
+            </cpu>
+            <topology>
+              <cells num='1'>
+                <cell id='0'>
+                  <cpus num='4'>
+                    <cpu id='0' socket_id='0' core_id='0' siblings='0,2'/>
+                    <cpu id='1' socket_id='0' core_id='1' siblings='1,3'/>
+                    <cpu id='2' socket_id='0' core_id='0' siblings='0,2'/>
+                    <cpu id='3' socket_id='0' core_id='1' siblings='1,3'/>
+                  </cpus>
+                </cell>
+              </cells>
+            </topology>
+          </host>
+        </capabilities>
+        """
+        self.assertTrue(self.host.has_hyperthreading)
+
+    @mock.patch('nova.virt.libvirt.host.libvirt.Connection.getCapabilities')
+    def test_has_hyperthreading__false(self, mock_cap):
+        mock_cap.return_value = """
+        <capabilities>
+          <host>
+            <uuid>1f71d34a-7c89-45cf-95ce-3df20fc6b936</uuid>
+            <cpu>
+            </cpu>
+            <topology>
+              <cells num='1'>
+                <cell id='0'>
+                  <cpus num='4'>
+                    <cpu id='0' socket_id='0' core_id='0' siblings='0'/>
+                    <cpu id='1' socket_id='0' core_id='1' siblings='1'/>
+                    <cpu id='2' socket_id='0' core_id='2' siblings='2'/>
+                    <cpu id='3' socket_id='0' core_id='3' siblings='3'/>
+                  </cpus>
+                </cell>
+              </cells>
+            </topology>
+          </host>
+        </capabilities>
+        """
+        self.assertFalse(self.host.has_hyperthreading)
+
 
 vc = fakelibvirt.virConnect
 

nova/virt/libvirt/driver.py

@@ -357,8 +357,8 @@ class LibvirtDriver(driver.ComputeDriver):
         self._initiator = None
         self._fc_wwnns = None
         self._fc_wwpns = None
-        self._caps = None
         self._supported_perf_events = []
+        self.__has_hyperthreading = None
         self.firewall_driver = firewall.load_driver(
             DEFAULT_FIREWALL_DRIVER,
             host=self._host)
@@ -10269,6 +10269,8 @@ class LibvirtDriver(driver.ComputeDriver):
         """
         traits = self._get_cpu_feature_traits()
         traits[ot.HW_CPU_X86_AMD_SEV] = self._host.supports_amd_sev
+        traits[ot.HW_CPU_HYPERTHREADING] = self._host.has_hyperthreading
+
         return traits
 
     def _get_cpu_feature_traits(self):

nova/virt/libvirt/host.py

@@ -119,6 +119,8 @@ class Host(object):
         # memoized by the supports_amd_sev property below.
         self._supports_amd_sev = None
 
+        self._has_hyperthreading = None
+
     @staticmethod
     def _get_libvirt_proxy_classes(libvirt_module):
         """Return a tuple for tpool.Proxy's autowrap argument containing all
@@ -1188,6 +1190,26 @@ class Host(object):
         except IOError:
             return False
 
+    @property
+    def has_hyperthreading(self):
+        """Determine if host CPU has SMT, a.k.a. HyperThreading.
+
+        :return: True if the host has SMT enabled, else False.
+        """
+        if self._has_hyperthreading is not None:
+            return self._has_hyperthreading
+
+        self._has_hyperthreading = False
+
+        # we don't use '/capabilities/host/cpu/topology' since libvirt doesn't
+        # guarantee the accuracy of this information
+        for cell in self.get_capabilities().host.topology.cells:
+            if any(len(cpu.siblings) > 1 for cpu in cell.cpus if cpu.siblings):
+                self._has_hyperthreading = True
+                break
+
+        return self._has_hyperthreading
+
     def _kernel_supports_amd_sev(self):
         if not os.path.exists(SEV_KERNEL_PARAM_FILE):
             LOG.debug("%s does not exist", SEV_KERNEL_PARAM_FILE)