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

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Message-ID: <YKP+CavM21klDHH8@kernel.org>
Date:   Tue, 18 May 2021 20:48:57 +0300
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     Reinette Chatre <reinette.chatre@...el.com>
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

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.

/Jarkko