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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 8570EC433DF for ; Fri, 15 May 2020 09:29:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F90D20709 for ; Fri, 15 May 2020 09:29:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728068AbgEOJ3L (ORCPT ); Fri, 15 May 2020 05:29:11 -0400 Received: from mga01.intel.com ([192.55.52.88]:12703 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727803AbgEOJ3L (ORCPT ); Fri, 15 May 2020 05:29:11 -0400 IronPort-SDR: d+jTClX5I0+L5e8W3uS9auM09vExF6e61j2kF0OVqMIdh6ax9ZfjrdtH5Y1L3Q/AGnn+3jNVUQ 5yEhufWYMwBg== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 May 2020 02:29:11 -0700 IronPort-SDR: zgcyaOJzmdHEPg9rE9q61hQ8kEuO3zkyxDgVzKRV6TU7FG25D9MqCP+h8YFquR2iICtuA4jfoJ hVVhQakx9Gqw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,394,1583222400"; d="scan'208";a="464664998" Received: from mgpinon-mobl.ger.corp.intel.com ([10.252.55.74]) by fmsmga005.fm.intel.com with ESMTP; 15 May 2020 02:29:03 -0700 Message-ID: <666f4c3865fcd92e7d5c8437e69399cb55fb88a9.camel@linux.intel.com> Subject: Re: [PATCH v29 00/20] Intel SGX foundations From: Jarkko Sakkinen To: Borislav Petkov , Sean Christopherson Cc: "Dr. Greg" , Thomas Gleixner , torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org, akpm@linux-foundation.org, dave.hansen@intel.com, nhorman@redhat.com, npmccallum@redhat.com, haitao.huang@intel.com, andriy.shevchenko@linux.intel.com, kai.svahn@intel.com, josh@joshtriplett.org, luto@kernel.org, kai.huang@intel.com, rientjes@google.com, cedric.xing@intel.com, puiterwijk@redhat.com In-Reply-To: <20200514162054.GE9266@zn.tnic> References: <20200421215316.56503-1-jarkko.sakkinen@linux.intel.com> <20200426165753.GA11046@wind.enjellic.com> <87d07gk24l.fsf@nanos.tec.linutronix.de> <20200508190226.GA31465@wind.enjellic.com> <20200508195635.GR27052@linux.intel.com> <20200514091637.GA25156@wind.enjellic.com> <20200514161559.GA15603@linux.intel.com> <20200514162054.GE9266@zn.tnic> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Date: Fri, 15 May 2020 12:28:54 +0300 User-Agent: Evolution 3.36.1-2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2020-05-14 at 18:20 +0200, Borislav Petkov wrote: > On Thu, May 14, 2020 at 09:15:59AM -0700, Sean Christopherson wrote: > > I'm not opposed to adding a kernel param to disable SGX. At one point > > there was a proposal to extend clearcpuid to allow disabling multiple > > feature bits, but it looks like that went the way of the dodo. > > > > Note, such a param would disable SGX entirely, e.g. clear the feature bit > > in /proc/cpuinfo and prevent any in-kernel SGX code from running. > > It is a usual practice for big features like SGX to add a > "nosgx" cmdline param to disable it in case something goes > south. We do this for all features - see all "no*" switches in > Documentation/admin-guide/kernel-parameters.txt Uh oh, should probably address this. Should I send v31 today with a "nosgx" patch added? Sorry for missing this one :-/ /Jarkko