Re: [PATCH 0/4] cxl: Add KUnit tests and documentation

[Dave Jiang <dave.jiang@intel.com>]

On 10/13/26 9:17 PM, Alison Schofield wrote:
> The CXL subsystem has no KUnit tests. Its automated test coverage comes
> from cxl_test and the ndctl suite, which exercise the driver stack through
> an emulated CXL topology. KUnit complements that coverage by testing self-
> contained logic and error paths in isolation.
> 
> This series introduces CXL KUnit infrastructure and documentation describing
> how it complements the existing cxl_test coverage.
> 
> The first KUnit suite, a collection of related test cases, exercises the HDM
> decoder interleave encoding helpers, providing a starting point for testing
> self-contained CXL logic. The second suite exercises mailbox command handling,
> including error paths that are difficult to reach through cxl_test.
> 
> The mailbox tests also demonstrate the value of regression coverage. An
> unknown device return code can cause an out-of-bounds read and allow a failed
> command to be reported as successful. The series corrects that behavior, then
> adds tests that reproduce the failure without the correction. With KASAN enabled,
> the tests also expose the out-of-bounds read.
> 
> Together, the two suites establish a pattern for adding KUnit coverage
> to CXL, both for existing functionality and for bugs as they are found.
> 
> 
> 
> Alison Schofield (3):
>   Documentation/driver-api/cxl: Add a testing page
>   cxl: Add KUnit tests for HDM decoder encoding helpers
>   cxl/mbox: Add KUnit tests for cxl_internal_send_cmd()
> 
> Gaobin Huang (1):
>   cxl/mbox: Treat unknown device return codes as errors
> 
>  Documentation/driver-api/cxl/index.rst   |   1 +
>  Documentation/driver-api/cxl/testing.rst | 120 +++++++++++
>  drivers/cxl/.kunitconfig                 |   4 +
>  drivers/cxl/Kconfig                      |  16 ++
>  drivers/cxl/Makefile                     |   1 +
>  drivers/cxl/core/Makefile                |   1 +
>  drivers/cxl/core/tests/Makefile          |   5 +
>  drivers/cxl/core/tests/mbox_kunit.c      | 249 +++++++++++++++++++++++
>  drivers/cxl/cxlmem.h                     |   6 +
>  drivers/cxl/tests/Makefile               |   5 +
>  drivers/cxl/tests/hdm_encoding_kunit.c   | 156 ++++++++++++++
>  11 files changed, 564 insertions(+)
>  create mode 100644 Documentation/driver-api/cxl/testing.rst
>  create mode 100644 drivers/cxl/.kunitconfig
>  create mode 100644 drivers/cxl/core/tests/Makefile
>  create mode 100644 drivers/cxl/core/tests/mbox_kunit.c
>  create mode 100644 drivers/cxl/tests/Makefile
>  create mode 100644 drivers/cxl/tests/hdm_encoding_kunit.c
> 

Nice! For the series,
Reviewed-by: Dave Jiang <dave.jiang@intel.com>