[PATCH] Documentation: kunit: add description of kunit.enable parameter

[Yuya Ishikawa <ishikawa.yuy-00@jp.fujitsu.com>]

The current KUnit documentation does not mention the kunit.enable
kernel parameter, making it unclear how to troubleshoot cases where
KUnit tests do not run as expected.
Add a note explaining kunit.enable parmaeter. Disabling this parameter
prevents all KUnit tests from running even if CONFIG_KUNIT is enabled.

Signed-off-by: Yuya Ishikawa <ishikawa.yuy-00@jp.fujitsu.com>
---
 Documentation/dev-tools/kunit/run_manual.rst | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/dev-tools/kunit/run_manual.rst b/Documentation/dev-tools/kunit/run_manual.rst
index 699d92885075..98e8d5b28808 100644
--- a/Documentation/dev-tools/kunit/run_manual.rst
+++ b/Documentation/dev-tools/kunit/run_manual.rst
@@ -35,6 +35,12 @@ or be built into the kernel.
 	a good way of quickly testing everything applicable to the current
 	config.
 
+	KUnit can be enabled or disabled at boot time, and this behavior is
+	controlled by the kunit.enable kernel parameter.
+	By default, kunit.enable is set to 1 because KUNIT_DEFAULT_ENABLED is
+	enabled by default. To ensure that tests are executed as expected,
+	verify that kunit.enable=1 at boot time.
+
 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``)
-- 
2.47.3