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 3939BC433E1 for ; Thu, 23 Jul 2020 16:25:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E1AA206D8 for ; Thu, 23 Jul 2020 16:25:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728873AbgGWQZh (ORCPT ); Thu, 23 Jul 2020 12:25:37 -0400 Received: from mga05.intel.com ([192.55.52.43]:65237 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726632AbgGWQZh (ORCPT ); Thu, 23 Jul 2020 12:25:37 -0400 IronPort-SDR: 2AZZtCpMRl6rdpflwQT/go8rG8nf0ll4r3ufYmO3Wvfdw+L1LDo1pNskbbwXkv9BwgZGA6L3We SY7rTGw1WBvQ== X-IronPort-AV: E=McAfee;i="6000,8403,9691"; a="235441446" X-IronPort-AV: E=Sophos;i="5.75,387,1589266800"; d="scan'208";a="235441446" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jul 2020 09:25:36 -0700 IronPort-SDR: 7SNQbhgfLF8y+Ls0u3O0LezOL/4DKnkZUziPl6WdpxFftOFptAKIedxZcyo2AanJGfyBajYaF7 F/KSAtvgmIzA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,387,1589266800"; d="scan'208";a="488426080" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.152]) by fmsmga006.fm.intel.com with ESMTP; 23 Jul 2020 09:25:31 -0700 Date: Thu, 23 Jul 2020 09:25:31 -0700 From: Sean Christopherson To: Yu-cheng Yu Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang Subject: Re: [PATCH v10 00/26] Control-flow Enforcement: Shadow Stack Message-ID: <20200723162531.GF21891@linux.intel.com> References: <20200429220732.31602-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200429220732.31602-1-yu-cheng.yu@intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-api-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Wed, Apr 29, 2020 at 03:07:06PM -0700, Yu-cheng Yu wrote: > Control-flow Enforcement (CET) is a new Intel processor feature that blocks > return/jump-oriented programming attacks. Details can be found in "Intel > 64 and IA-32 Architectures Software Developer's Manual" [1]. > > This series depends on the XSAVES supervisor state series that was split > out and submitted earlier [2]. ... > Yu-cheng Yu (25): > x86/cpufeatures: Add CET CPU feature flags for Control-flow > Enforcement Technology (CET) > x86/fpu/xstate: Introduce CET MSR XSAVES supervisor states How would people feel about taking the above two patches (02 and 03 in the series) through the KVM tree to enable KVM virtualization of CET before the kernel itself gains CET support? I.e. add the MSR and feature bits, along with the XSAVES context switching. The feature definitons could use "" to suppress displaying them in /proc/cpuinfo to avoid falsely advertising CET to userspace. AIUI, there are ABI issues that need to be sorted out, and that is likely going to drag on for some time. Is this a "hell no" sort of idea, or something that would be feasible if we can show that there are no negative impacts to the kernel?