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From:   Andy Lutomirski <luto@kernel.org>
Date:   Mon, 25 Mar 2019 16:59:30 -0700
Message-ID: <CALCETrXqb3CHefN-RLudC61jwdbLFS8cXuS4V5OJ6HTuf_arYw@mail.gmail.com>
Subject: Re: [PATCH v19,RESEND 24/27] x86/vdso: Add __vdso_sgx_enter_enclave()
 to wrap SGX enclave transitions
To:     Sean Christopherson <sean.j.christopherson@intel.com>
Cc:     "Xing, Cedric" <cedric.xing@intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "x86@kernel.org" <x86@kernel.org>,
        "linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
        "Hansen, Dave" <dave.hansen@intel.com>,
        "nhorman@redhat.com" <nhorman@redhat.com>,
        "npmccallum@redhat.com" <npmccallum@redhat.com>,
        "Ayoun, Serge" <serge.ayoun@intel.com>,
        "Katz-zamir, Shay" <shay.katz-zamir@intel.com>,
        "Huang, Haitao" <haitao.huang@intel.com>,
        "andriy.shevchenko@linux.intel.com" 
        <andriy.shevchenko@linux.intel.com>,
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        Dave Hansen <dave.hansen@linux.intel.com>,
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        "Dr . Greg Wettstein" <greg@enjellic.com>
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On Mon, Mar 25, 2019 at 11:03 AM Sean Christopherson
<sean.j.christopherson@intel.com> wrote:
>
> On Sun, Mar 24, 2019 at 01:59:48AM -0700, Xing, Cedric wrote:
> > As said in my previous email, this vDSO API isn't even compliant to
> > x86_64 ABI and is absolutely NOT for average developers. Instead,
> > host/enclave communications are expected to be handled by SDKs and
> > those developers will be very aware of the limitations of their targeted
> > environments, and will need the freedom to deploy optimal solutions.

> I fully realize that the above approach saddles Cedric and the SDK team
> with the extra task of justifying the need for two vDSO interfaces, and
> likely reduces the probability of their proposal being accepted.  But, we
> don't *force* the SDK to be rewritten, and we gain a vDSO interface that
> many people want and is acceptable to the maintainers (unless I've
> horribly misread Andy's position).

I don't think you've horribly misread it.  I would like to keep the
stuff in the vDSO as minimal as possible.  If we need to add a fancier
interface down the line, then that's fine.