[RFC PATCH 1/2] kunit: tool: Move qemu architecture dependency checks into a function

[RFC PATCH 1/2] kunit: tool: Move qemu architecture dependency checks into a function

[David Gow]

Currently the RISC-V qemu architecture config has some code to check for
the presence of the BIOS files before loading, printing a message and
quitting if it's not present.

However, this prevents us from loading the architecture file even just
to inspect it if the dependencies are not present. Instead, have kunit.py
look for a check_dependencies function, and call it if present only when
the architecture config is being used.

This is necessary for future changes which enumerate or automatically
select an architecture.

Signed-off-by: David Gow <davidgow@google.com>
---
 tools/testing/kunit/kunit_kernel.py       |  5 +++++
 tools/testing/kunit/qemu_configs/riscv.py | 10 ++++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
index 260d8d9aa1db..c3201a76da24 100644
--- a/tools/testing/kunit/kunit_kernel.py
+++ b/tools/testing/kunit/kunit_kernel.py
@@ -230,6 +230,11 @@ def _get_qemu_ops(config_path: str,
 	assert isinstance(spec.loader, importlib.abc.Loader)
 	spec.loader.exec_module(config)
 
+	# Check for any per-architecture dependencies
+	if hasattr(config, 'check_dependencies'):
+		if not config.check_dependencies():
+			raise ValueError('Missing dependencies for ' + config_path)
+
 	if not hasattr(config, 'QEMU_ARCH'):
 		raise ValueError('qemu_config module missing "QEMU_ARCH": ' + config_path)
 	params: qemu_config.QemuArchParams = config.QEMU_ARCH
diff --git a/tools/testing/kunit/qemu_configs/riscv.py b/tools/testing/kunit/qemu_configs/riscv.py
index c87758030ff7..3c271d1005d9 100644
--- a/tools/testing/kunit/qemu_configs/riscv.py
+++ b/tools/testing/kunit/qemu_configs/riscv.py
@@ -6,10 +6,12 @@ import sys
 OPENSBI_FILE = 'opensbi-riscv64-generic-fw_dynamic.bin'
 OPENSBI_PATH = '/usr/share/qemu/' + OPENSBI_FILE
 
-if not os.path.isfile(OPENSBI_PATH):
-	print('\n\nOpenSBI bios was not found in "' + OPENSBI_PATH + '".\n'
-	      'Please ensure that qemu-system-riscv is installed, or edit the path in "qemu_configs/riscv.py"\n')
-	sys.exit()
+def check_dependencies() -> bool:
+    if not os.path.isfile(OPENSBI_PATH):
+	    print('\n\nOpenSBI bios was not found in "' + OPENSBI_PATH + '".\n'
+	          'Please ensure that qemu-system-riscv is installed, or edit the path in "qemu_configs/riscv.py"\n')
+	    return False
+    return True
 
 QEMU_ARCH = QemuArchParams(linux_arch='riscv',
 			   kconfig='''
-- 
2.50.1.552.g942d659e1b-goog

[RFC PATCH 2/2] kunit: tool: Automatically pick a default architecture if none is specified

[David Gow]

Currently, kunit.py will default to 'um' (User-Mode Linux) if no specific
--arch option is given. However, UML is only available on x86-based
architectures, so kunit.py fails by default on anything else.

Instead, for non-x86 architectures, enumerate the qemu configs looking
for one which matches the current architecture. This currently uses
`uname -m`, which doesn't always match the kernel/kunit's architecture
name (e.g., aarch64 versus arm64), so look at both the kernel and qemu
architecture names in the qemu config until one matches.

With this change `./tools/testing/kunit/kunit.py run` should function
out-of-the-box on most non-x86 architectures, assuming qemu is installed.

Signed-off-by: David Gow <davidgow@google.com>
---
 tools/testing/kunit/kunit.py           |  2 +-
 tools/testing/kunit/kunit_kernel.py    | 43 ++++++++++++++++++++------
 tools/testing/kunit/kunit_tool_test.py | 10 +++---
 3 files changed, 40 insertions(+), 15 deletions(-)

diff --git a/tools/testing/kunit/kunit.py b/tools/testing/kunit/kunit.py
index 7f9ae55fd6d5..188bb7f2802f 100755
--- a/tools/testing/kunit/kunit.py
+++ b/tools/testing/kunit/kunit.py
@@ -351,7 +351,7 @@ def add_common_opts(parser: argparse.ArgumentParser) -> None:
 				  'string passed to the ARCH make param, '
 				  'e.g. i386, x86_64, arm, um, etc. Non-UML '
 				  'architectures run on QEMU.'),
-			    type=str, default='um', metavar='ARCH')
+			    type=str, metavar='ARCH')
 
 	parser.add_argument('--cross_compile',
 			    help=('Sets make\'s CROSS_COMPILE variable; it should '
diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
index c3201a76da24..7042e44e3a88 100644
--- a/tools/testing/kunit/kunit_kernel.py
+++ b/tools/testing/kunit/kunit_kernel.py
@@ -211,6 +211,31 @@ def _default_qemu_config_path(arch: str) -> str:
 
 	raise ConfigError(arch + ' is not a valid arch, options are ' + str(sorted(options)))
 
+def _detect_default_architecture() -> str:
+	uname_arch = os.uname().machine
+
+	options = [f[:-3] for f in os.listdir(QEMU_CONFIGS_DIR) if f.endswith('.py')]
+
+	if uname_arch == 'x86_64' or uname_arch == 'i486' or uname_arch == 'i586' or uname_arch == 'i686':
+		return 'um'
+
+	for option in options:
+		config_path = os.path.join(QEMU_CONFIGS_DIR, option + '.py')
+		module_path = '.' + os.path.join(os.path.basename(QEMU_CONFIGS_DIR), os.path.basename(config_path))
+		spec = importlib.util.spec_from_file_location(module_path, config_path)
+		assert spec is not None
+		config = importlib.util.module_from_spec(spec)
+		# See https://github.com/python/typeshed/pull/2626 for context.
+		assert isinstance(spec.loader, importlib.abc.Loader)
+		spec.loader.exec_module(config)
+
+		if config.QEMU_ARCH.linux_arch == uname_arch:
+			return option
+		if config.QEMU_ARCH.qemu_arch == uname_arch:
+			return option
+
+	raise ConfigError('Could not find a valid config for ' + uname_arch + ', options are ' + str(sorted(options)))
+
 def _get_qemu_ops(config_path: str,
 		  extra_qemu_args: Optional[List[str]],
 		  cross_compile: Optional[str]) -> Tuple[str, LinuxSourceTreeOperations]:
@@ -247,19 +272,19 @@ class LinuxSourceTree:
 	"""Represents a Linux kernel source tree with KUnit tests."""
 
 	def __init__(
-	      self,
-	      build_dir: str,
-	      kunitconfig_paths: Optional[List[str]]=None,
-	      kconfig_add: Optional[List[str]]=None,
-	      arch: Optional[str]=None,
-	      cross_compile: Optional[str]=None,
-	      qemu_config_path: Optional[str]=None,
-	      extra_qemu_args: Optional[List[str]]=None) -> None:
+		  self,
+		  build_dir: str,
+		  kunitconfig_paths: Optional[List[str]]=None,
+		  kconfig_add: Optional[List[str]]=None,
+		  arch: Optional[str]=None,
+		  cross_compile: Optional[str]=None,
+		  qemu_config_path: Optional[str]=None,
+		  extra_qemu_args: Optional[List[str]]=None) -> None:
 		signal.signal(signal.SIGINT, self.signal_handler)
 		if qemu_config_path:
 			self._arch, self._ops = _get_qemu_ops(qemu_config_path, extra_qemu_args, cross_compile)
 		else:
-			self._arch = 'um' if arch is None else arch
+			self._arch = _detect_default_architecture() if arch is None else arch
 			if self._arch == 'um':
 				self._ops = LinuxSourceTreeOperationsUml(cross_compile=cross_compile)
 			else:
diff --git a/tools/testing/kunit/kunit_tool_test.py b/tools/testing/kunit/kunit_tool_test.py
index bbba921e0eac..a3dd456d62cd 100755
--- a/tools/testing/kunit/kunit_tool_test.py
+++ b/tools/testing/kunit/kunit_tool_test.py
@@ -747,7 +747,7 @@ class KUnitMainTest(unittest.TestCase):
 		self.mock_linux_init.assert_called_once_with('.kunit',
 						kunitconfig_paths=['mykunitconfig'],
 						kconfig_add=None,
-						arch='um',
+						arch=None,
 						cross_compile=None,
 						qemu_config_path=None,
 						extra_qemu_args=[])
@@ -758,7 +758,7 @@ class KUnitMainTest(unittest.TestCase):
 		self.mock_linux_init.assert_called_once_with('.kunit',
 						kunitconfig_paths=['mykunitconfig'],
 						kconfig_add=None,
-						arch='um',
+						arch=None,
 						cross_compile=None,
 						qemu_config_path=None,
 						extra_qemu_args=[])
@@ -769,7 +769,7 @@ class KUnitMainTest(unittest.TestCase):
 		self.mock_linux_init.assert_called_once_with('.kunit',
 						kunitconfig_paths=[kunit_kernel.ALL_TESTS_CONFIG_PATH, 'mykunitconfig'],
 						kconfig_add=None,
-						arch='um',
+						arch=None,
 						cross_compile=None,
 						qemu_config_path=None,
 						extra_qemu_args=[])
@@ -783,7 +783,7 @@ class KUnitMainTest(unittest.TestCase):
 		mock_linux_init.assert_called_once_with('.kunit',
 							kunitconfig_paths=['mykunitconfig', 'other'],
 							kconfig_add=None,
-							arch='um',
+							arch=None,
 							cross_compile=None,
 							qemu_config_path=None,
 							extra_qemu_args=[])
@@ -794,7 +794,7 @@ class KUnitMainTest(unittest.TestCase):
 		self.mock_linux_init.assert_called_once_with('.kunit',
 						kunitconfig_paths=[],
 						kconfig_add=['CONFIG_KASAN=y', 'CONFIG_KCSAN=y'],
-						arch='um',
+						arch=None,
 						cross_compile=None,
 						qemu_config_path=None,
 						extra_qemu_args=[])
-- 
2.50.1.552.g942d659e1b-goog