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,NICE_REPLY_A,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 859D5C4707A for ; Fri, 21 May 2021 18:32:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 58A4F613DB for ; Fri, 21 May 2021 18:32:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235382AbhEUSeF (ORCPT ); Fri, 21 May 2021 14:34:05 -0400 Received: from mga06.intel.com ([134.134.136.31]:33957 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232583AbhEUSeE (ORCPT ); Fri, 21 May 2021 14:34:04 -0400 IronPort-SDR: C4NGxBNoobTzXsEqsxAUfQD+OHDCK/05vPL4pAa3OzlrXzoZJPFzgvlUGjokr9CKyEc4T/meLH sSHlIf/xUwNg== X-IronPort-AV: E=McAfee;i="6200,9189,9991"; a="262764131" X-IronPort-AV: E=Sophos;i="5.82,319,1613462400"; d="scan'208";a="262764131" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 May 2021 11:32:40 -0700 IronPort-SDR: xuimTYhQfkQ8M5AjUfAoJr+h9etA8CXp8+j1k+A+K6QRs2+UeRZAgxsesoMUovRMvi40PDj7au KgjtoRfxxovA== X-IronPort-AV: E=Sophos;i="5.82,319,1613462400"; d="scan'208";a="441193981" Received: from orxpovpvmu02.amr.corp.intel.com (HELO skuppusw-mobl5.amr.corp.intel.com) ([10.213.181.51]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 May 2021 11:32:39 -0700 Subject: Re: [RFC v2-fix-v2 1/1] x86/boot: Avoid #VE during boot for TDX platforms To: Dave Hansen , Sean Christopherson Cc: Peter Zijlstra , Andy Lutomirski , Tony Luck , Andi Kleen , Kirill Shutemov , Kuppuswamy Sathyanarayanan , Dan Williams , Raj Ashok , linux-kernel@vger.kernel.org, Sean Christopherson References: <20210521143524.2527690-1-sathyanarayanan.kuppuswamy@linux.intel.com> <9a23d1c3-a443-6142-52b4-7594123030fb@intel.com> From: "Kuppuswamy, Sathyanarayanan" Message-ID: Date: Fri, 21 May 2021 11:32:36 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <9a23d1c3-a443-6142-52b4-7594123030fb@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/21/21 11:30 AM, Dave Hansen wrote: > That sounds sane to me. It would be nice to get this into the > changelog. Perhaps: > > This theoretically makes guest boot more fragile. If, for > instance, EER was set up incorrectly and a WRMSR was performed, > the resulting (unhandled) #VE would triple fault. However, this > is likely to trip up the guest BIOS long before control reaches > the kernel. In any case, these kinds of problems are unlikely > to occur in production environments, and developers have good > debug tools to fix them quickly. > > That would put my mind at ease a bit. I can add it to change log. -- Sathyanarayanan Kuppuswamy Linux Kernel Developer