linux-kernel - Re: [PATCH v28 21/22] x86/vdso: Implement a vDSO for Intel SGX enclave call

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20d3cc40d559a854a7984543acdacb61a2d51b8d.camel@linux.intel.com>
Date:   Mon, 16 Mar 2020 23:27:03 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Nathaniel McCallum <npmccallum@...hat.com>,
        Jethro Beekman <jethro@...tanix.com>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        linux-sgx@...r.kernel.org, akpm@...ux-foundation.org,
        dave.hansen@...el.com,
        "Christopherson, Sean J" <sean.j.christopherson@...el.com>,
        Neil Horman <nhorman@...hat.com>,
        "Huang, Haitao" <haitao.huang@...el.com>,
        andriy.shevchenko@...ux.intel.com, tglx@...utronix.de,
        "Svahn, Kai" <kai.svahn@...el.com>, bp@...en8.de,
        Josh Triplett <josh@...htriplett.org>, luto@...nel.org,
        kai.huang@...el.com, David Rientjes <rientjes@...gle.com>,
        cedric.xing@...el.com, Patrick Uiterwijk <puiterwijk@...hat.com>,
        Andy Lutomirski <luto@...capital.net>,
        Connor Kuehl <ckuehl@...hat.com>,
        Harald Hoyer <harald@...hat.com>,
        Lily Sturmann <lsturman@...hat.com>
Subject: Re: [PATCH v28 21/22] x86/vdso: Implement a vDSO for Intel SGX
 enclave call

On Mon, 2020-03-16 at 09:57 -0400, Nathaniel McCallum wrote:
> For the vDSO, only marginally. I'm counting +4,-2 instructions in my
> suggestions. For the wrapper, things become significantly simpler.

Simpler is not a quality that has very high importance here except
when it comes to vDSO.

At least it is not enough to change to vDSO. What else?

Anyway, I think the documentation should fixed and streamlined 1st.

It is way too verbose prose in some places and in some it completely
lacks the information e.g.

"Debug Exceptions (#DB) and Breakpoints (#BP) are ever fixed up and are
always delivered via standard signals."

Never should state things like that without explaining the reasons.

On the other hand:

"Most exceptions reported on ENCLU, including those that occur within
the enclave, are fixed up and reported synchronously instead of being
delivered via a standard signal. Debug Exceptions (#DB) and Breakpoints
(#BP) are never fixed up and are always delivered via standard signals.
On synchrously reported exceptions, -EFAULT is returned and details
about the exception are recorded in @e, the optional
sgx_enclave_exception struct."

Duplicates information already elsewhere (e.g. return values) and is
just pain to read and comprehend in general.

/Jarkko