New option to prevent libvirt defining boot order

Add a new config option "SUSHY_EMULATOR_IGNORE_BOOT_DEVICE".
Instructs the libvirt driver to ignore any instructions to
set the boot device. Allowing the UEFI firmware to instead
rely on the EFI Boot Manager

Change-Id: Ica78dab39639d7acb2168866b0035f9c3d865fa1

doc/source/admin/emulator.conf

@@ -19,6 +19,15 @@ SUSHY_EMULATOR_OS_CLOUD = None
 # The libvirt URI to use. This option enables libvirt driver.
 SUSHY_EMULATOR_LIBVIRT_URI = u'qemu:///system'
 
+# Instruct the libvirt driver to ignore any instructions to
+# set the boot device. Allowing the UEFI firmware to instead
+# rely on the EFI Boot Manager
+# Note: This sets the legacy boot element to dev="fd"
+# and relies on the floppy not existing, it likely wont work
+# your VM has a floppy drive.
+SUSHY_EMULATOR_IGNORE_BOOT_DEVICE = False
+
+
 # The map of firmware loaders dependant on the boot mode and
 # system architecture
 SUSHY_EMULATOR_BOOT_LOADER_MAP = {

sushy_tools/emulator/resources/systems/libvirtdriver.py

@@ -155,6 +155,8 @@ class LibvirtDriver(AbstractSystemsDriver):
             'SUSHY_EMULATOR_BOOT_LOADER_MAP', cls.BOOT_LOADER_MAP)
         cls.KNOWN_BOOT_LOADERS = set(y for x in cls.BOOT_LOADER_MAP.values()
                                      for y in x.values())
+        cls.SUSHY_EMULATOR_IGNORE_BOOT_DEVICE = \
+            cls._config.get('SUSHY_EMULATOR_IGNORE_BOOT_DEVICE', False)
         return cls
 
     @memoize.memoize()
@@ -282,6 +284,11 @@ class LibvirtDriver(AbstractSystemsDriver):
         :returns: boot device name as `str` or `None` if device name
             can't be determined
         """
+
+        # If not setting Boot devices then just report HDD
+        if self.SUSHY_EMULATOR_IGNORE_BOOT_DEVICE:
+            return constants.DEVICE_TYPE_HDD
+
         domain = self._get_domain(identity, readonly=True)
 
         tree = ET.fromstring(domain.XMLDesc(libvirt.VIR_DOMAIN_XML_INACTIVE))
@@ -347,6 +354,15 @@ class LibvirtDriver(AbstractSystemsDriver):
 
         return boot_source_target
 
+    def _defineDomain(self, tree):
+        try:
+            with libvirt_open(self._uri) as conn:
+                conn.defineXML(ET.tostring(tree).decode('utf-8'))
+        except libvirt.libvirtError as e:
+            msg = ('Error changing boot device at libvirt URI "%(uri)s": '
+                   '%(error)s' % {'uri': self._uri, 'error': e})
+            raise error.FishyError(msg)
+
     def set_boot_device(self, identity, boot_source):
         """Get/Set computer system boot device name
 
@@ -372,6 +388,13 @@ class LibvirtDriver(AbstractSystemsDriver):
             for boot_element in os_element.findall('boot'):
                 os_element.remove(boot_element)
 
+            if self.SUSHY_EMULATOR_IGNORE_BOOT_DEVICE:
+                self._logger.warning('Ignoring setting of boot device')
+                boot_element = ET.SubElement(os_element, 'boot')
+                boot_element.set('dev', 'fd')
+                self._defineDomain(tree)
+                return
+
         target = self.DISK_DEVICE_MAP.get(boot_source)
 
         # Process per-device boot configuration
@@ -426,15 +449,7 @@ class LibvirtDriver(AbstractSystemsDriver):
             boot_element = ET.SubElement(target_device_element, 'boot')
             boot_element.set('order', str(order + 1))
 
-        try:
-            with libvirt_open(self._uri) as conn:
-                conn.defineXML(ET.tostring(tree).decode('utf-8'))
-
-        except libvirt.libvirtError as e:
-            msg = ('Error changing boot device at libvirt URI "%(uri)s": '
-                   '%(error)s' % {'uri': self._uri, 'error': e})
-
-            raise error.FishyError(msg)
+        self._defineDomain(tree)
 
     def get_boot_mode(self, identity):
         """Get computer system boot mode.

sushy_tools/tests/unit/emulator/resources/systems/test_libvirt.py

@@ -214,6 +214,27 @@ class LibvirtDriverTestCase(base.BaseTestCase):
 
         conn_mock.defineXML.assert_called_once_with(mock.ANY)
 
+    @mock.patch('libvirt.open', autospec=True)
+    def test_set_boot_device_ignored(self, libvirt_mock):
+        with open('sushy_tools/tests/unit/emulator/'
+                  'domain_boot_os.xml', 'r') as f:
+            data = f.read()
+
+        conn_mock = libvirt_mock.return_value
+        domain_mock = conn_mock.lookupByUUID.return_value
+        domain_mock.XMLDesc.return_value = data
+
+        self.test_driver.SUSHY_EMULATOR_IGNORE_BOOT_DEVICE = True
+
+        self.test_driver.set_boot_device(self.uuid, 'Hdd')
+
+        conn_mock.defineXML.assert_called_once_with(mock.ANY)
+        tree = ET.fromstring(conn_mock.defineXML.call_args[0][0])
+        self.assertEqual(1, len(tree.findall('.//boot')))
+        os_element = tree.find('os')
+        boot_element = os_element.find('boot')
+        self.assertEqual('fd', boot_element.get('dev'))
+
     @mock.patch('libvirt.openReadOnly', autospec=True)
     def test_get_boot_device_disk(self, libvirt_mock):
         with open('sushy_tools/tests/unit/emulator/'