From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC14EC43444 for ; Sun, 23 Dec 2018 12:52:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 930FE2075B for ; Sun, 23 Dec 2018 12:52:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728415AbeLWMwb (ORCPT ); Sun, 23 Dec 2018 07:52:31 -0500 Received: from mga04.intel.com ([192.55.52.120]:22583 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725868AbeLWMwb (ORCPT ); Sun, 23 Dec 2018 07:52:31 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Dec 2018 04:52:30 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,386,1539673200"; d="scan'208";a="112774162" Received: from dlu2-mobl4.ccr.corp.intel.com (HELO localhost) ([10.249.254.240]) by orsmga003.jf.intel.com with ESMTP; 23 Dec 2018 04:52:24 -0800 Date: Sun, 23 Dec 2018 14:52:22 +0200 From: Jarkko Sakkinen To: Andy Lutomirski , Sean Christopherson Cc: Jethro Beekman , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "x86@kernel.org" , Dave Hansen , Peter Zijlstra , "H. Peter Anvin" , "linux-kernel@vger.kernel.org" , "linux-sgx@vger.kernel.org" , Josh Triplett , Haitao Huang , "Dr . Greg Wettstein" Subject: Re: x86/sgx: uapi change proposal Message-ID: <20181223125114.GA7051@linux.intel.com> References: <20181214215729.4221-1-sean.j.christopherson@intel.com> <7706b2aa71312e1f0009958bcab24e1e9d8d1237.camel@linux.intel.com> <598cd050-f0b5-d18c-96a0-915f02525e3e@fortanix.com> <20181219091148.GA5121@linux.intel.com> <613c6814-4e71-38e5-444a-545f0e286df8@fortanix.com> <20181219144515.GA30909@linux.intel.com> <20181220103204.GB26410@linux.intel.com> <20181222081649.GB8895@linux.intel.com> <20181222082502.GA13275@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181222082502.GA13275@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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Dec 22, 2018 at 10:25:02AM +0200, Jarkko Sakkinen wrote: > On Sat, Dec 22, 2018 at 10:16:49AM +0200, Jarkko Sakkinen wrote: > > On Thu, Dec 20, 2018 at 12:32:04PM +0200, Jarkko Sakkinen wrote: > > > On Wed, Dec 19, 2018 at 06:58:48PM -0800, Andy Lutomirski wrote: > > > > Can one of you explain why SGX_ENCLAVE_CREATE is better than just > > > > opening a new instance of /dev/sgx for each encalve? > > > > > > I think that fits better to the SCM_RIGHTS scenario i.e. you could send > > > the enclav to a process that does not have necessarily have rights to > > > /dev/sgx. Gives more robust environment to configure SGX. > > > > Sean, is this why you wanted enclave fd and anon inode and not just use > > the address space of /dev/sgx? Just taking notes of all observations. > > I'm not sure what your rationale was (maybe it was somewhere). This was > > something I made up, and this one is wrong deduction. You can easily > > get the same benefit with /dev/sgx associated fd representing the > > enclave. > > > > This all means that for v19 I'm going without enclave fd involved with > > fd to /dev/sgx representing the enclave. No anon inodes will be > > involved. > > Based on these observations I updated the uapi. > > As far as I'm concerned there has to be a solution to do EPC mapping > with a sequence: > > 1. Ping /dev/kvm to do something. > 2. KVM asks SGX core to do something. > 3. SGX core does something. > > I don't care what the something is exactly is, but KVM is the only sane > place for KVM uapi. I would be surprised if KVM maintainers didn't agree > that they don't want to sprinkle KVM uapi to random places in other > subsystems. The one option to consider to do would be to have a device driver for KVM if you really want this e.g. something like /dev/vsgx. With the current knowledge I'm not yet sure why all could not be done just through /dev/kvm. /Jarkko