kunit: tool: Enable virtio/PCI by default on UML

There are several tests which depend on PCI, and hence need a bunch of
extra options to run under UML. This makes it awkward to give
configuration instructions (whether in documentation, or as part of a
.kunitconfig file), as two separate, incompatible sets of config options
are required for UML and "most other architectures".

For non-UML architectures, it's possible to add default kconfig options
via the qemu_config python files, but there's no equivalent for UML. Add
a new tools/testing/kunit/configs/arch_uml.config file containing extra
kconfig options to use on UML.

Tested-by: José Expósito <[e-mail]>
Reviewed-by: Daniel Latypov <[e-mail]>
Signed-off-by: David Gow <[e-mail]>
Reviewed-by: Brendan Higgins <[e-mail]>
Signed-off-by: Daniel Latypov <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

tools/testing/kunit/configs/arch_uml.config

···
+# Config options which are added to UML builds by default
+
+# Enable virtio/pci, as a lot of tests require it.
+CONFIG_VIRTIO_UML=y
+CONFIG_UML_PCI_OVER_VIRTIO=y

tools/testing/kunit/kunit_kernel.py

···
 OLD_KUNITCONFIG_PATH = 'last_used_kunitconfig'
 DEFAULT_KUNITCONFIG_PATH = 'tools/testing/kunit/configs/default.config'
 BROKEN_ALLCONFIG_PATH = 'tools/testing/kunit/configs/broken_on_uml.config'
+UML_KCONFIG_PATH = 'tools/testing/kunit/configs/arch_uml.config'
 OUTFILE_PATH = 'test.log'
 ABS_TOOL_PATH = os.path.abspath(os.path.dirname(__file__))
 QEMU_CONFIGS_DIR = os.path.join(ABS_TOOL_PATH, 'qemu_configs')
···
 		except subprocess.CalledProcessError as e:
 			raise ConfigError(e.output.decode())
 
-	def make_arch_qemuconfig(self, base_kunitconfig: kunit_config.Kconfig) -> kunit_config.Kconfig:
+	def make_arch_config(self, base_kunitconfig: kunit_config.Kconfig) -> kunit_config.Kconfig:
 		return base_kunitconfig
 
 	def make_allyesconfig(self, build_dir: str, make_options) -> None:
···
 		self._kernel_command_line = qemu_arch_params.kernel_command_line + ' kunit_shutdown=reboot'
 		self._extra_qemu_params = qemu_arch_params.extra_qemu_params
 
-	def make_arch_qemuconfig(self, base_kunitconfig: kunit_config.Kconfig) -> kunit_config.Kconfig:
+	def make_arch_config(self, base_kunitconfig: kunit_config.Kconfig) -> kunit_config.Kconfig:
 		kconfig = kunit_config.parse_from_string(self._kconfig)
 		kconfig.merge_in_entries(base_kunitconfig)
 		return kconfig
···
 
 	def __init__(self, cross_compile=None):
 		super().__init__(linux_arch='um', cross_compile=cross_compile)
+
+	def make_arch_config(self, base_kunitconfig: kunit_config.Kconfig) -> kunit_config.Kconfig:
+		kconfig = kunit_config.parse_file(UML_KCONFIG_PATH)
+		kconfig.merge_in_entries(base_kunitconfig)
+		return kconfig
 
 	def make_allyesconfig(self, build_dir: str, make_options) -> None:
 		stdout.print_with_timestamp(
···
 		if build_dir and not os.path.exists(build_dir):
 			os.mkdir(build_dir)
 		try:
-			self._kconfig = self._ops.make_arch_qemuconfig(self._kconfig)
+			self._kconfig = self._ops.make_arch_config(self._kconfig)
 			self._kconfig.write_to_file(kconfig_path)
 			self._ops.make_olddefconfig(build_dir, make_options)
 		except ConfigError as e:
···
 			return self.build_config(build_dir, make_options)
 
 		existing_kconfig = kunit_config.parse_file(kconfig_path)
-		self._kconfig = self._ops.make_arch_qemuconfig(self._kconfig)
+		self._kconfig = self._ops.make_arch_config(self._kconfig)
 
 		if self._kconfig.is_subset_of(existing_kconfig) and not self._kunitconfig_changed(build_dir):
 			return True

tools/testing/kunit/kunit_tool_test.py

···
 				f.write('CONFIG_KUNIT=y')
 
 			tree = kunit_kernel.LinuxSourceTree(build_dir)
+			# Stub out the source tree operations, so we don't have
+			# the defaults for any given architecture get in the
+			# way.
+			tree._ops = kunit_kernel.LinuxSourceTreeOperations('none', None)
 			mock_build_config = mock.patch.object(tree, 'build_config').start()
 
 			# Should generate the .config
···
 				f.write('CONFIG_KUNIT=y\nCONFIG_KUNIT_TEST=y')
 
 			tree = kunit_kernel.LinuxSourceTree(build_dir)
+			# Stub out the source tree operations, so we don't have
+			# the defaults for any given architecture get in the
+			# way.
+			tree._ops = kunit_kernel.LinuxSourceTreeOperations('none', None)
 			mock_build_config = mock.patch.object(tree, 'build_config').start()
 
 			self.assertTrue(tree.build_reconfig(build_dir, make_options=[]))
···
 				f.write('CONFIG_KUNIT=y\nCONFIG_KUNIT_TEST=y')
 
 			tree = kunit_kernel.LinuxSourceTree(build_dir)
+			# Stub out the source tree operations, so we don't have
+			# the defaults for any given architecture get in the
+			# way.
+			tree._ops = kunit_kernel.LinuxSourceTreeOperations('none', None)
 			mock_build_config = mock.patch.object(tree, 'build_config').start()
 
 			# ... so we should trigger a call to build_config()