Re: [PATCH bpf-next v2 2/2] bpf/selftests: Add a short note about run_in_vm.sh in README.rst

[Yonghong Song <yhs@fb.com>]

On 1/22/21 4:44 PM, KP Singh wrote:
> Add a short note to make contributors aware of the existence of the
> script. The documentation does not intentionally document all the
> options of the script to avoid mentioning it in two places (it's
> available in the usage / help message of the script).
> 
> Signed-off-by: KP Singh <kpsingh@kernel.org>

Acked-by: Yonghong Song <yhs@fb.com>

> ---
>   tools/testing/selftests/bpf/README.rst | 23 +++++++++++++++++++++++
>   1 file changed, 23 insertions(+)
> 
> diff --git a/tools/testing/selftests/bpf/README.rst b/tools/testing/selftests/bpf/README.rst
> index ca064180d4d0..a0dac65b6b01 100644
> --- a/tools/testing/selftests/bpf/README.rst
> +++ b/tools/testing/selftests/bpf/README.rst
> @@ -6,6 +6,29 @@ General instructions on running selftests can be found in
>   
>   __ /Documentation/bpf/bpf_devel_QA.rst#q-how-to-run-bpf-selftests
>   
> +=========================
> +Running Selftests in a VM
> +=========================
> +
> +It's now possible to run the selftests using ``tools/testing/selftests/bpf/run_in_vm.sh``.
> +The script tries to ensure that the tests are run with the same environment as they
> +would be run post-submit in the CI used by the Maintainers.
> +
> +This script downloads a suitable Kconfig and VM userspace image from the system used by
> +the CI. It builds the kernel (without overwriting your existing Kconfig), recompiles the
> +bpf selftests, runs them (by default ``tools/testing/selftests/bpf/test_progs``) and
> +saves the resulting output (by default in ``~/.bpf_selftests``).
> +
> +For more information on about using the script, run:
> +
> +.. code-block:: console
> +
> +	$ tools/testing/selftests/bpf/run_in_vm.sh -h
> +
> +.. note:: The script does not yet update pahole and LLVM, so these will still need to be
> +          manually updated.
Maybe a little more clarification and actionable.

The script uses pahole and clang based on host environment setting.
If you want to change pahole and llvm, you can change PATH env variable 
in the beginning of script.

I did not test changing PATH env variable inside the script, but I think
it should work.

> +
> +.. note:: The script currently only supports x86_64.
>   
>   Additional information about selftest failures are
>   documented here.
>