Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 19 Dec 2018 07:13:01 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To:     Sean Christopherson <sean.j.christopherson@intel.com>
Cc:     Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@intel.com>, X86 ML <x86@kernel.org>,
        Platform Driver <platform-driver-x86@vger.kernel.org>,
        linux-sgx@vger.kernel.org, nhorman@redhat.com,
        npmccallum@redhat.com, "Ayoun, Serge" <serge.ayoun@intel.com>,
        shay.katz-zamir@intel.com,
        Haitao Huang <haitao.huang@linux.intel.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        "Svahn, Kai" <kai.svahn@intel.com>, mark.shanahan@intel.com,
        Suresh Siddha <suresh.b.siddha@intel.com>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Darren Hart <dvhart@infradead.org>,
        Andy Shevchenko <andy@infradead.org>,
        "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" 
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v17 18/23] platform/x86: Intel SGX driver
Message-ID: <20181219051301.GA15175@linux.intel.com>
References: <20181217180102.GA12560@linux.intel.com>
 <20181217183613.GD12491@linux.intel.com>
 <20181217184333.GA26920@linux.intel.com>
 <ccfb67a0-fd8d-82c8-8018-fd68e901f287@intel.com>
 <CALCETrX0W4dhFJBHEbDbKed_QZxmw6ZNMajfsoVgqGqhMB0nDg@mail.gmail.com>
 <20181217222047.GG12491@linux.intel.com>
 <CALCETrX1HXZvMk8UM6wV5StTj+vvqehAvybJYk66At60t91QGQ@mail.gmail.com>
 <20181218154417.GC28326@linux.intel.com>
 <20181218185349.GC30082@linux.intel.com>
 <20181219050047.GC14295@linux.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20181219050047.GC14295@linux.intel.com>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Dec 19, 2018 at 07:00:47AM +0200, Jarkko Sakkinen wrote:
> On Tue, Dec 18, 2018 at 10:53:49AM -0800, Sean Christopherson wrote:
> > What if we re-organize the ioctls in such a way that we leave open the
> > possibility of allocating raw EPC for KVM via /dev/sgx?  I'm not 100%
> > positive this approach will work[1], but conceptually it fits well with
> > KVM's memory model, e.g. KVM is aware of the GPA<->HVA association but
> > generally speaking doesn't know what's physically backing each memory
> > region.
> 
> Why would you want to pass EPC through user space to KVM rather than
> KVM allocating it through kernel interfaces?
> 
> > Tangentially related, I think we should support allocating multiple
> > enclaves from a single /dev/sgx fd, i.e. a process shouldn't have to
> > open /dev/sgx every time it wants to create a new enclave.
> 
> I'm fine with this. It just requires to create anon inode. I'll just
> add a new field called 'enclave_fd' to struct sgx_enclave_create and
> that's all.
> 
> I think I have otherwise ingredients for v19 ready except where to swap.

If I follow your proposal here and allow to create multiple enclaves
(i.e. with anon inodes for each) with one descriptor, is that sufficient
API to later add what you want to KVM?

/Jarkko