[PATCH v2] kunit: tool: Implement listing of available architectures

["Thomas Weißschuh" <thomas.weissschuh@linutronix.de>]

To implement custom scripting around kunit.py it is useful to get a list of
available architectures. While it is possible to manually inspect
tools/testing/kunit/qemu_configs/, this is annoying to implement and
introduces a dependency on a kunit.py implementation detail.

Introduce 'kunit.py run --arch help' which lists all known architectures
in an easy to parse list. This is equivalent on how QEMU implements
listing of possible argument values.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Rae Moar <rmoar@google.com>
---
Changes in v2:
- Pick up review from Rae
- Link to v1: https://lore.kernel.org/r/20250220-kunit-list-v1-1-40b9d56417ee@linutronix.de
---
 Documentation/dev-tools/kunit/run_wrapper.rst | 2 ++
 tools/testing/kunit/kunit_kernel.py           | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/Documentation/dev-tools/kunit/run_wrapper.rst b/Documentation/dev-tools/kunit/run_wrapper.rst
index 19ddf5e07013314c608b570e297a8ff79a8efe7f..6697c71ee8ca020b8ac7e91b46e29ab082d9dea0 100644
--- a/Documentation/dev-tools/kunit/run_wrapper.rst
+++ b/Documentation/dev-tools/kunit/run_wrapper.rst
@@ -182,6 +182,8 @@ via UML. To run tests on qemu, by default it requires two flags:
   is ignored), the tests will run via UML. Non-UML architectures,
   for example: i386, x86_64, arm and so on; run on qemu.
 
+  ``--arch help`` lists all valid ``--arch`` values.
+
 - ``--cross_compile``: Specifies the Kbuild toolchain. It passes the
   same argument as passed to the ``CROSS_COMPILE`` variable used by
   Kbuild. As a reminder, this will be the prefix for the toolchain
diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
index d3f39bc1ceec7eab23925ff1b852e996a715f3d5..260d8d9aa1db4ac3c04fa755fb738dd834b976db 100644
--- a/tools/testing/kunit/kunit_kernel.py
+++ b/tools/testing/kunit/kunit_kernel.py
@@ -14,6 +14,7 @@ import os
 import shlex
 import shutil
 import signal
+import sys
 import threading
 from typing import Iterator, List, Optional, Tuple
 from types import FrameType
@@ -201,6 +202,13 @@ def _default_qemu_config_path(arch: str) -> str:
 		return config_path
 
 	options = [f[:-3] for f in os.listdir(QEMU_CONFIGS_DIR) if f.endswith('.py')]
+
+	if arch == 'help':
+		print('um')
+		for option in options:
+			print(option)
+		sys.exit()
+
 	raise ConfigError(arch + ' is not a valid arch, options are ' + str(sorted(options)))
 
 def _get_qemu_ops(config_path: str,

---
base-commit: 8ffd015db85fea3e15a77027fda6c02ced4d2444
change-id: 20250220-kunit-list-552a8cdc011e

Best regards,
-- 
Thomas Weißschuh <thomas.weissschuh@linutronix.de>