Accept both 1 and Y as AMD SEV KVM kernel param value

The libvirt virt dirver checks the AMD KVM kernel module parameter SEV
to see if that feature is enabled. However it seems that the
/sys/module/kvm_amd/parameters/sev file can either contain "1\n" or
"Y\n" to indicate that the feature is enabled. Nova only checked for
"1\n" so far making the feature disabled on compute nodes with "Y\n"
value. Now the logic is extended to accept both.

Closes-Bug: #1975686
Change-Id: I737e1d73242430b6756178eb0bf9bd6ec5c94160

Author: gibizer

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

@@ -16,6 +16,7 @@
 
 import os
 
+import ddt
 import eventlet
 from eventlet import greenthread
 from eventlet import tpool
@@ -1947,26 +1948,34 @@ def setUp(self):
         self.host = host.Host("qemu:///system")
 
 
+@ddt.ddt
 class TestLibvirtSEVUnsupported(TestLibvirtSEV):
     @mock.patch.object(os.path, 'exists', return_value=False)
     def test_kernel_parameter_missing(self, fake_exists):
         self.assertFalse(self.host._kernel_supports_amd_sev())
         fake_exists.assert_called_once_with(
             '/sys/module/kvm_amd/parameters/sev')
 
+    @ddt.data(
+        ('0\n', False),
+        ('N\n', False),
+        ('1\n', True),
+        ('Y\n', True),
+    )
+    @ddt.unpack
     @mock.patch.object(os.path, 'exists', return_value=True)
-    @mock.patch('builtins.open', mock.mock_open(read_data="0\n"))
-    def test_kernel_parameter_zero(self, fake_exists):
-        self.assertFalse(self.host._kernel_supports_amd_sev())
-        fake_exists.assert_called_once_with(
-            '/sys/module/kvm_amd/parameters/sev')
-
-    @mock.patch.object(os.path, 'exists', return_value=True)
-    @mock.patch('builtins.open', mock.mock_open(read_data="1\n"))
-    def test_kernel_parameter_one(self, fake_exists):
-        self.assertTrue(self.host._kernel_supports_amd_sev())
-        fake_exists.assert_called_once_with(
-            '/sys/module/kvm_amd/parameters/sev')
+    def test_kernel_parameter(
+        self, sev_param_value, expected_support, mock_exists
+    ):
+        with mock.patch(
+            'builtins.open', mock.mock_open(read_data=sev_param_value)
+        ):
+            self.assertIs(
+                expected_support,
+                self.host._kernel_supports_amd_sev()
+            )
+            mock_exists.assert_called_once_with(
+                '/sys/module/kvm_amd/parameters/sev')
 
     @mock.patch.object(os.path, 'exists', return_value=True)
     @mock.patch('builtins.open', mock.mock_open(read_data="1\n"))

nova/virt/libvirt/host.py

@@ -46,6 +46,7 @@
 from oslo_serialization import jsonutils
 from oslo_utils import excutils
 from oslo_utils import importutils
+from oslo_utils import strutils
 from oslo_utils import units
 from oslo_utils import versionutils
 
@@ -1699,9 +1700,9 @@ def _kernel_supports_amd_sev(self) -> bool:
             return False
 
         with open(SEV_KERNEL_PARAM_FILE) as f:
-            contents = f.read()
-            LOG.debug("%s contains [%s]", SEV_KERNEL_PARAM_FILE, contents)
-            return contents == "1\n"
+            content = f.read()
+            LOG.debug("%s contains [%s]", SEV_KERNEL_PARAM_FILE, content)
+            return strutils.bool_from_string(content)
 
     @property
     def supports_amd_sev(self) -> bool: