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Date:   Tue, 10 Mar 2020 15:08:18 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To:     "Dr. Greg" <greg@enjellic.com>
Cc:     Nathaniel McCallum <npmccallum@redhat.com>,
        linux-kernel@vger.kernel.org, x86@kernel.org,
        linux-sgx@vger.kernel.org, akpm@linux-foundation.org,
        dave.hansen@intel.com,
        "Christopherson, Sean J" <sean.j.christopherson@intel.com>,
        Neil Horman <nhorman@redhat.com>,
        "Huang, Haitao" <haitao.huang@intel.com>,
        andriy.shevchenko@linux.intel.com, tglx@linutronix.de,
        "Svahn, Kai" <kai.svahn@intel.com>, bp@alien8.de,
        Josh Triplett <josh@joshtriplett.org>, luto@kernel.org,
        kai.huang@intel.com, rientjes@google.com, cedric.xing@intel.com,
        Patrick Uiterwijk <puiterwijk@redhat.com>,
        linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v28 14/22] selftests/x86: Add a selftest for SGX
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On Sat, Mar 07, 2020 at 11:42:23AM -0600, Dr. Greg wrote:
> On Fri, Mar 06, 2020 at 09:07:53PM +0200, Jarkko Sakkinen wrote:
> 
> Good morning, I hope the weekend is going well for everyone.
> 
> > Actually many people have applaused to have a small scoped, even if
> > not perfect, test program to look at how SGX works. One that is only
> > dependent on glibc. None of the selftests are meant to be production
> > peaces of code. You are getting wrong the role of the selftest in
> > the first place.
> 
> We certainly want to be counted in the camp of those who are
> applausing you for making the selftests available, particularly the
> new VDSO setup and entry code.
> 
> We arguably have similar motivations.  We architected and authored an
> entire SGX runtime that has as its only dependencies the MUSL C
> library, libelf and OpenSSL, primarily because we needed an easily
> auditable and low footprint SGX implementation.

Good to hear!

> To the point at hand though, I'm certainly not a very smart guy so I
> doubt that I am able to understand the role of the selftests.  We do
> seem to agree though that they only provide a rudimentary exercise of
> the driver.

The role of kselftests is not to be production code. They are somewhat
adhoc pieces of code that just check that "things turn on" e.g. in a
new kernel release or a new hardware platform.

> We also seem to agree that the primary role of the driver is to
> service the needs of those of us that are building production level
> SGX runtime stacks.  In service of that premise, it would be helpful
> to know if you are internally testing the driver/VDSO against enclaves
> of production quality, with metadata, or just the two page selftest
> enclave.

I do agree that a more complete test suite would be an essential thing
to have. In that I'd just use the SDK and implement it outside the
kernel tree.

Unfortunately I do not have time to implement such.

/Jarkko