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=-5.3 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 55A43C41604 for ; Tue, 6 Oct 2020 15:30:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 04873206DD for ; Tue, 6 Oct 2020 15:30:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726012AbgJFPax (ORCPT ); Tue, 6 Oct 2020 11:30:53 -0400 Received: from mga04.intel.com ([192.55.52.120]:49350 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725769AbgJFPax (ORCPT ); Tue, 6 Oct 2020 11:30:53 -0400 IronPort-SDR: ZNG5azsZl3wraXneFyZK0nUSgoNjDlrZfdWSec4iCUzWBKHdpFe9Mz+C0PqB+I6ElFslMJkJaX TOOYpm1PLUjQ== X-IronPort-AV: E=McAfee;i="6000,8403,9765"; a="161915881" X-IronPort-AV: E=Sophos;i="5.77,343,1596524400"; d="scan'208";a="161915881" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Oct 2020 08:15:35 -0700 IronPort-SDR: Ld8hUSmXzhhmCv51vSWvkEQIse22EktXhPt6YDefIVr2f33rzb4FsKm4nZeXZkdwOy+qoPioiy +Br3LSVF+cmQ== X-IronPort-AV: E=Sophos;i="5.77,343,1596524400"; d="scan'208";a="460838766" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.160]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Oct 2020 08:15:34 -0700 Date: Tue, 6 Oct 2020 08:15:32 -0700 From: Sean Christopherson To: Jethro Beekman Cc: Jarkko Sakkinen , x86@kernel.org, linux-sgx@vger.kernel.org, linux-kernel@vger.kernel.org, Andy Lutomirski , Cedric Xing , akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com, asapek@google.com, bp@alien8.de, chenalexchen@google.com, conradparker@google.com, cyhanish@google.com, dave.hansen@intel.com, haitao.huang@intel.com, kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com, ludloff@google.com, luto@kernel.org, nhorman@redhat.com, npmccallum@redhat.com, puiterwijk@redhat.com, rientjes@google.com, tglx@linutronix.de, yaozhangx@google.com, mikko.ylinen@intel.com Subject: Re: [PATCH v39 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Message-ID: <20201006151532.GA17610@linux.intel.com> References: <20201003045059.665934-1-jarkko.sakkinen@linux.intel.com> <20201003045059.665934-22-jarkko.sakkinen@linux.intel.com> <20201006025703.GG15803@linux.intel.com> <453c2d9b-0fd0-0d63-2bb9-096f255a6ff4@fortanix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <453c2d9b-0fd0-0d63-2bb9-096f255a6ff4@fortanix.com> User-Agent: Mutt/1.5.24 (2015-08-30) Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Tue, Oct 06, 2020 at 10:30:16AM +0200, Jethro Beekman wrote: > On 2020-10-06 04:57, Sean Christopherson wrote: > > On Sat, Oct 03, 2020 at 07:50:56AM +0300, Jarkko Sakkinen wrote: > >> +struct sgx_enclave_run { > >> + __u64 tcs; > >> + __u64 user_handler; > >> + __u64 user_data; > >> + __u32 leaf; > > > > I am still very strongly opposed to omitting exit_reason. It is not at all > > difficult to imagine scenarios where 'leaf' alone is insufficient for the > > caller or its handler to deduce why the CPU exited the enclave. E.g. see > > Jethro's request for intercepting interrupts. > > Not entirely sure what this has to do with my request, I just expect to see > leaf=ERESUME in this case, I think? E.g. as you would see in EAX when calling > ENCLU. But how would you differentiate from the case that an exception occured in the enclave? That will also transfer control with leaf=ERESUME. If there was a prior exception and userspace didn't zero out the struct, there would be "valid" data in the exception fields. An exit_reason also would allow retrofitting the exception fields into a union, i.e. the fields are valid if and only if exit_reason is exception.