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 1915DC48BCD for ; Wed, 9 Jun 2021 04:27:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2BA4601FC for ; Wed, 9 Jun 2021 04:27:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231476AbhFIE3o (ORCPT ); Wed, 9 Jun 2021 00:29:44 -0400 Received: from mga02.intel.com ([134.134.136.20]:3083 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229638AbhFIE3n (ORCPT ); Wed, 9 Jun 2021 00:29:43 -0400 IronPort-SDR: ggVz6ONT0wxMqoSJFz1LIHZ8Q42QZ2ShUwES1UFzNj5qn3Fp36QwpDLFxNxbgkqaZD/6LXHDH5 OO4Hw75oBe5Q== X-IronPort-AV: E=McAfee;i="6200,9189,10009"; a="192108947" X-IronPort-AV: E=Sophos;i="5.83,260,1616482800"; d="scan'208";a="192108947" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jun 2021 21:27:49 -0700 IronPort-SDR: HeCT/nqKrfuPjAXu1ylWArnlL11/p3d4W1Mpk4F9c7ii3IHEscWqrq749+a4ZB7i78+bc7B+g6 nsmkqNOmc+Bw== X-IronPort-AV: E=Sophos;i="5.83,260,1616482800"; d="scan'208";a="551854385" Received: from akleen-mobl1.amr.corp.intel.com (HELO [10.209.24.11]) ([10.209.24.11]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jun 2021 21:27:49 -0700 Subject: Re: [RFC v2-fix-v4 1/1] x86/tdx: Skip WBINVD instruction for TDX guest To: Dan Williams , "Kuppuswamy, Sathyanarayanan" Cc: Peter Zijlstra , Andy Lutomirski , Dave Hansen , Tony Luck , Kirill Shutemov , Kuppuswamy Sathyanarayanan , Raj Ashok , Sean Christopherson , Linux Kernel Mailing List References: <20210609011030.751451-1-sathyanarayanan.kuppuswamy@linux.intel.com> <682f0239-8da0-3702-0f14-99b6244af499@linux.intel.com> From: Andi Kleen Message-ID: Date: Tue, 8 Jun 2021 21:27:48 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org here is no resume path. > Host is free to go into S3 independent of any guest state. Actually my understanding is that none of the systems which support TDX support S3. S3 has been deprecated for a long time. > A hostile > host is free to do just enough cache management so that it can resume > from S3 while arranging for TDX guest dirty data to be lost. Does a > TDX guest go fatal if the cache loses power? That would be a machine check, and yes it would be fatal. -Andi