linux-kernel - Re: [PATCH v5 2/2] selftests/sgx: Migrate to kselftest harness

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Date:   Tue, 18 May 2021 13:07:16 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     Jarkko Sakkinen <jarkko@...nel.org>
Cc:     shuah@...nel.org, linux-kselftest@...r.kernel.org,
        linux-sgx@...r.kernel.org,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 2/2] selftests/sgx: Migrate to kselftest harness

Hi Jarkko,

On 5/18/2021 12:57 PM, Jarkko Sakkinen wrote:
> On Tue, May 18, 2021 at 08:49:00PM +0300, Jarkko Sakkinen wrote:
>> On Mon, May 17, 2021 at 10:03:42AM -0700, Reinette Chatre wrote:
>>> Hi Jarkko,
>>>
>>> On 5/12/2021 2:53 PM, Jarkko Sakkinen wrote:
>>>> Migrate to kselftest harness. Use a fixture test with enclave initialized
>>>> and de-initialized for each of the existing three tests, in other words:
>>>>
>>>> 1. One FIXTURE() for managing the enclave life-cycle.
>>>> 2. Three TEST_F()'s, one for each test case.
>>>>
>>>> This gives a leaps better reporting than before. Here's an example
>>>> transcript:
>>>>
>>>> TAP version 13
>>>> 1..3
>>>>
>>>> ok 1 enclave.unclobbered_vdso
>>>>
>>>> ok 2 enclave.clobbered_vdso
>>>>
>>>> ok 3 enclave.clobbered_vdso_and_user_function
>>>>
>>>> Signed-off-by: Jarkko Sakkinen <jarkko@...nel.org>
>>>> ---
>>>>
>>>> v5:
>>>> * Use TH_LOG() for printing enclave address ranges instead of printf(),
>>>>     based on Reinette's remark.
>>>
>>> Thank you for considering my feedback. The motivation for my comment was to
>>> consider how this test output will be parsed. If these tests will have their
>>> output parsed by automated systems then it needs to conform to the TAP13
>>> format as supported by kselftest.
>>>
>>> In your latest version the output printed during a successful test has been
>>> changed, using TH_LOG() as you noted. From what I can tell this is the only
>>> output addressed - failing tests continue to print error messages (perror,
>>> fprintf) without consideration of how they will be parsed. My apologies, I
>>> am not a kselftest expert to know what the best way for this integration is.
>>>
>>> Reinette
>>
>> It's a valid question, yes.
>>
>> The problem is that only main.c can use kselftest macros because
>> kselftest_harness.h pulls
>>
>> static int test_harness_run(int __attribute__((unused)) argc,
>> 			    char __attribute__((unused)) **argv)
>>
>> which will not end up having a call site (because there's no
>> "TEST_HARNESS_MAIN").
>>
>> The whole logging thing in kselftest harness is a bit ambiguous.
>> Namely:
>>
>> 1. There's a macro TH_LOG() defined in kselftest_harness.h, which
>>     "internally" uses fprintf().
>> 2. There's an inline function ksft_print_msg() in kselftest.h
>>     using vsprintf().
>>
>> To add to that, kselftest_harness.h internally prints by using
>> ksft_print_msg(), and provides TH_LOG(), which does not use
>> ksft_print_msg().
>>
>> I don't really get the logic in all this.
> 
> I tried to split TH_LOG() as separate entity but it's not possible, as the
> macros access a static variable called '_metadata'.
> 
> I'm not exactly sure how to proceed from this, if we want to make logging
> consistent.
> 
> I would personally suggest to leave the error messages intact in load.c,
> because there is no way to make them consistent, except by removing them.


It is not clear to me why ksft_print_msg() cannot be used but an 
alternative to it may be to just prefix all existing diagnostic messages 
with "# ".

Reinette