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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 6B93DC433E0 for ; Mon, 10 Aug 2020 23:48:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3CD58206E9 for ; Mon, 10 Aug 2020 23:48:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726913AbgHJXsk (ORCPT ); Mon, 10 Aug 2020 19:48:40 -0400 Received: from mga07.intel.com ([134.134.136.100]:48551 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726978AbgHJXsj (ORCPT ); Mon, 10 Aug 2020 19:48:39 -0400 IronPort-SDR: z3lwRyZA7YRybpY3dY4GFZepudjTzrEA+LvZ4/8Ai+p4JHKbGra4k4xXPGW2+NJ6b1G4Ighi/a KwanpFpEej8Q== X-IronPort-AV: E=McAfee;i="6000,8403,9709"; a="217973005" X-IronPort-AV: E=Sophos;i="5.75,458,1589266800"; d="scan'208";a="217973005" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Aug 2020 16:48:38 -0700 IronPort-SDR: 8cgDxUS+J1VzRgt8O8sKhAzt0TsHWt7cPUUWJzbs+R17gBvfWk4vrdWtk7/qVtMmZ20AMoPCUc sVpfB1qa4UMQ== X-IronPort-AV: E=Sophos;i="5.75,458,1589266800"; d="scan'208";a="290520811" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.160]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Aug 2020 16:48:38 -0700 Date: Mon, 10 Aug 2020 16:48:37 -0700 From: Sean Christopherson To: Andy Lutomirski Cc: Nathaniel McCallum , Jarkko Sakkinen , X86 ML , linux-sgx@vger.kernel.org, LKML , Jethro Beekman , Cedric Xing , Andrew Morton , Andy Shevchenko , asapek@google.com, Borislav Petkov , chenalexchen@google.com, Conrad Parker , cyhanish@google.com, Dave Hansen , "Huang, Haitao" , Josh Triplett , "Huang, Kai" , "Svahn, Kai" , Keith Moyer , Christian Ludloff , Neil Horman , Patrick Uiterwijk , David Rientjes , Thomas Gleixner , yaozhangx@google.com Subject: Re: [PATCH v36 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Message-ID: <20200810234837.GH14724@linux.intel.com> References: <20200716135303.276442-1-jarkko.sakkinen@linux.intel.com> <20200716135303.276442-22-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Mon, Aug 10, 2020 at 04:08:46PM -0700, Andy Lutomirski wrote: > What am I missing? I still don't really understand why we are > supporting this mechanism at all. Just the asm code to invoke the > callback seems to be about half of the entire function. Because the Intel SDK (and other SDKs?) wants to use the host stack to pass parameters out of the enclave.