libvirt: add ps2mouse in choice for pointer_model

This commit adds option ps2mouse to pointer_model, and set the default
value of pointer_model to usbtablet to do not break upgrade regarding
the default behavior of use_usb_tablet.

WHY: use_usb_tablet is by default set to True and during the
deprecation phase of use_usb_tablet, operators which have set that
option to false can't have the same behavior by using pointer_model
since use_usb_tablet takes precedence. Now operators can use
pointer_model=ps2mouse.

Change-Id: Id18b5503799922e4096bde296a9e7bb4f2a994aa
Closes-Bug: #1621582

nova/conf/virt.py

@@ -272,7 +272,8 @@ Unused unresized base images younger than this will not be removed
 
     cfg.StrOpt(
         'pointer_model',
-        choices=[None, 'usbtablet'],
+        default='usbtablet',
+        choices=[None, 'ps2mouse', 'usbtablet'],
         help="""
 Generic property to specify the pointer type.
 
@@ -284,7 +285,9 @@ this configuration option.
 
 Possible values:
 
-* None: Uses relative movement. Mouse connected by PS2
+* None: Uses default behavior provided by drivers (mouse on PS2 for
+        libvirt x86)
+* ps2mouse: Uses relative movement. Mouse connected by PS2
 * usbtablet: Uses absolute movement. Tablet connect by USB
 
 Interdependencies to other options:

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

@@ -3419,9 +3419,8 @@ class LibvirtConnTestCase(test.NoDBTestCase):
 
     def test_get_guest_config_with_vnc(self):
         self.flags(enabled=True, group='vnc')
-        self.flags(virt_type='kvm',
-                   use_usb_tablet=False,
-                   group='libvirt')
+        self.flags(virt_type='kvm', group='libvirt')
+        self.flags(pointer_model='ps2mouse')
         self.flags(enabled=False, group='spice')
 
         drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
@@ -4144,6 +4143,12 @@ class LibvirtConnTestCase(test.NoDBTestCase):
         image_meta = objects.ImageMeta.from_dict(image_meta)
         return drvr._get_guest_pointer_model(os_type, image_meta)
 
+    def test_use_ps2_mouse(self):
+        self.flags(pointer_model='ps2mouse')
+
+        tablet = self._test_get_guest_usb_tablet(True, True, vm_mode.HVM)
+        self.assertIsNone(tablet)
+
     def test_get_guest_usb_tablet_wipe(self):
         self.flags(use_usb_tablet=True, group='libvirt')
 
@@ -4206,12 +4211,14 @@ class LibvirtConnTestCase(test.NoDBTestCase):
 
     def test_get_guest_no_pointer_model_usb_tablet_set(self):
         self.flags(use_usb_tablet=True, group='libvirt')
+        self.flags(pointer_model=None)
 
         tablet = self._test_get_guest_usb_tablet(True, True, vm_mode.HVM)
         self.assertIsNotNone(tablet)
 
     def test_get_guest_no_pointer_model_usb_tablet_not_set(self):
         self.flags(use_usb_tablet=False, group='libvirt')
+        self.flags(pointer_model=None)
 
         tablet = self._test_get_guest_usb_tablet(True, True, vm_mode.HVM)
         self.assertIsNone(tablet)
@@ -4567,9 +4574,8 @@ class LibvirtConnTestCase(test.NoDBTestCase):
         self.assertEqual(cfg.devices[5].type, "vnc")
 
     def test_get_guest_config_with_rng_device(self):
-        self.flags(virt_type='kvm',
-                   use_usb_tablet=False,
-                   group='libvirt')
+        self.flags(virt_type='kvm', group='libvirt')
+        self.flags(pointer_model='ps2mouse')
 
         drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = objects.Instance(**self.test_instance)
@@ -4608,9 +4614,8 @@ class LibvirtConnTestCase(test.NoDBTestCase):
         self.assertIsNone(cfg.devices[6].rate_period)
 
     def test_get_guest_config_with_rng_not_allowed(self):
-        self.flags(virt_type='kvm',
-                   use_usb_tablet=False,
-                   group='libvirt')
+        self.flags(virt_type='kvm', group='libvirt')
+        self.flags(pointer_model='ps2mouse')
 
         drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = objects.Instance(**self.test_instance)
@@ -4641,9 +4646,8 @@ class LibvirtConnTestCase(test.NoDBTestCase):
                               vconfig.LibvirtConfigMemoryBalloon)
 
     def test_get_guest_config_with_rng_limits(self):
-        self.flags(virt_type='kvm',
-                   use_usb_tablet=False,
-                   group='libvirt')
+        self.flags(virt_type='kvm', group='libvirt')
+        self.flags(pointer_model='ps2mouse')
 
         drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = objects.Instance(**self.test_instance)
@@ -4686,9 +4690,9 @@ class LibvirtConnTestCase(test.NoDBTestCase):
     @mock.patch('nova.virt.libvirt.driver.os.path.exists')
     def test_get_guest_config_with_rng_backend(self, mock_path):
         self.flags(virt_type='kvm',
-                   use_usb_tablet=False,
                    rng_dev_path='/dev/hw_rng',
                    group='libvirt')
+        self.flags(pointer_model='ps2mouse')
         mock_path.return_value = True
 
         drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)

releasenotes/notes/default-value-pointer-model-cb3d9a3e9c51e503.yaml

@@ -0,0 +1,4 @@
+---
+upgrade:
+  - The default value of the ``pointer_model`` configuration option
+    has been set to 'usbtablet'.