[PATCH kunit 3/3] kunit: update documentation to describe debugfs representation

[Alan Maguire]

Documentation should describe debugfs layout and semantics.

Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
 Documentation/dev-tools/kunit/usage.rst | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst
index 7cd56a1..b1ebf9f 100644
--- a/Documentation/dev-tools/kunit/usage.rst
+++ b/Documentation/dev-tools/kunit/usage.rst
@@ -590,3 +590,23 @@ able to run one test case per invocation.
 
 .. TODO(brendanhiggins@xxxxxxxxxx): Add an actual example of an architecture
    dependent KUnit test.
+
+KUnit debugfs representation
+============================
+When kunit test suites are initialized, they create an associated directory
+in /sys/kernel/debug/kunit/<test-suite>.  The directory contains two files
+
+- results: "cat results" displays results of last test run
+- run: "cat run" runs the test suite and displays the results
+
+Thus to re-run all currently loaded suites and display results, we can do this:
+
+```
+$ cat /sys/kernel/debug/kunit/*/run
+```
+
+The debugfs representation is primarily of use when kunit test suites are
+run in a native environment, either as modules or builtin.  Having a way
+to display results like this is valuable as otherwise results can be
+intermixed with other events in dmesg output.
+
-- 
1.8.3.1