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+.. SPDX-License-Identifier: GPL-2.0
+
+============================
+Run Tests without kunit_tool
+============================
+
+If we do not want to use kunit_tool (For example: we want to integrate
+with other systems, or run tests on real hardware), we can
+include KUnit in any kernel, read out results, and parse manually.
+
+.. note:: KUnit is not designed for use in a production system. It is
+          possible that tests may reduce the stability or security of
+          the system.
+
+Configure the Kernel
+====================
+
+KUnit tests can run without kunit_tool. This can be useful, if:
+
+- We have an existing kernel configuration to test.
+- Need to run on real hardware (or using an emulator/VM kunit_tool
+  does not support).
+- Wish to integrate with some existing testing systems.
+
+KUnit is configured with the ``CONFIG_KUNIT`` option, and individual
+tests can also be built by enabling their config options in our
+``.config``. KUnit tests usually (but don't always) have config options
+ending in ``_KUNIT_TEST``. Most tests can either be built as a module,
+or be built into the kernel.
+
+.. note ::
+
+	We can enable the ``KUNIT_ALL_TESTS`` config option to
+	automatically enable all tests with satisfied dependencies. This is
+	a good way of quickly testing everything applicable to the current
+	config.
+
+Once we have built our kernel (and/or modules), it is simple to run
+the tests. If the tests are built-in, they will run automatically on the
+kernel boot. The results will be written to the kernel log (``dmesg``)
+in TAP format.
+
+If the tests are built as modules, they will run when the module is
+loaded.
+
+.. code-block :: bash
+
+	# modprobe example-test
+
+The results will appear in TAP format in ``dmesg``.
+
+debugfs
+=======
+
+KUnit can be accessed from userspace via the debugfs filesystem (See more
+information about debugfs at Documentation/filesystems/debugfs.rst).
+
+If ``CONFIG_KUNIT_DEBUGFS`` is enabled, the KUnit debugfs filesystem is
+mounted at /sys/kernel/debug/kunit. You can use this filesystem to perform
+the following actions.
+
+Retrieve Test Results
+=====================
+
+You can use debugfs to retrieve KUnit test results. The test results are
+accessible from the debugfs filesystem in the following read-only file:
+
+.. code-block :: bash
+
+	/sys/kernel/debug/kunit/<test_suite>/results
+
+The test results are printed in a KTAP document. Note this document is separate
+to the kernel log and thus, may have different test suite numbering.
+
+Run Tests After Kernel Has Booted
+=================================
+
+You can use the debugfs filesystem to trigger built-in tests to run after
+boot. To run the test suite, you can use the following command to write to
+the ``/sys/kernel/debug/kunit/<test_suite>/run`` file:
+
+.. code-block :: bash
+
+	echo "any string" > /sys/kernel/debugfs/kunit/<test_suite>/run
+
+As a result, the test suite runs and the results are printed to the kernel
+log.
+
+However, this feature is not available with KUnit suites that use init data,
+because init data may have been discarded after the kernel boots. KUnit
+suites that use init data should be defined using the
+kunit_test_init_section_suites() macro.
+
+Also, you cannot use this feature to run tests concurrently. Instead a test
+will wait to run until other tests have completed or failed.
+
+.. note ::
+
+	For test authors, to use this feature, tests will need to correctly initialise
+	and/or clean up any data, so the test runs correctly a second time.