Merge "libvirt: Stop unconditionally enabling evmcs"

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

@@ -28051,7 +28051,10 @@ class LibvirtDriverTestCase(test.NoDBTestCase, TraitsComparisonMixin):
         self.assertTrue(hv.reenlightenment)
         self.assertTrue(hv.tlbflush)
         self.assertTrue(hv.ipi)
-        self.assertTrue(hv.evmcs)
+        # NOTE(artom) evmcs only works on Intel hosts, so we can't enable it
+        # unconditionally. Until we become smarter about it, just don't enable
+        # it at all. See bug 2009280.
+        self.assertFalse(hv.evmcs)
 
 
 class LibvirtVolumeUsageTestCase(test.NoDBTestCase):

nova/virt/libvirt/driver.py

@@ -6265,7 +6265,6 @@ class LibvirtDriver(driver.ComputeDriver):
             hv.reenlightenment = True
             hv.tlbflush = True
             hv.ipi = True
-            hv.evmcs = True
 
             # NOTE(kosamara): Spoofing the vendor_id aims to allow the nvidia
             # driver to work on windows VMs. At the moment, the nvidia driver

releasenotes/notes/libvirt-enlightenments-stop-unconditionally-enabling-evmcs-993a825641c4b9f3.yaml

@@ -0,0 +1,8 @@
+---
+fixes:
+  - |
+    Bug 2009280 has been fixed by no longer enabling the evmcs enlightenment in
+    the libvirt driver. evmcs only works on Intel CPUs, and domains with that
+    enlightenment cannot be started on AMD hosts. There is a possible future
+    feature to enable support for generating this enlightenment only when
+    running on Intel hosts.