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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19073C433EF for ; Tue, 12 Oct 2021 21:00:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EFC6C60720 for ; Tue, 12 Oct 2021 21:00:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235069AbhJLVCG (ORCPT ); Tue, 12 Oct 2021 17:02:06 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:25180 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234787AbhJLVCD (ORCPT ); Tue, 12 Oct 2021 17:02:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1634072400; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Exp5E6dmY1PTSyKlOFa3gXPk4wQssFca5mHGxtbGag0=; b=igCTC4SM7jQR6qapOSFWL9jNvG9gX07POR3VmciQplPTVSGQ3ElgA0RNw0ZP49hiCd7Si5 xebfs9UCwTBAZMyKD6gHkCBYQ8Pz435UgOqpimFhX5oM7cXE+yZI0ZdDIWJk0ZFPvgbk65 FFKsvX22zCQrcTmUlfWAgPnpz1omz5Y= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-159-pR82M3jiPRW9Sex6G3JcWA-1; Tue, 12 Oct 2021 16:59:59 -0400 X-MC-Unique: pR82M3jiPRW9Sex6G3JcWA-1 Received: by mail-wr1-f71.google.com with SMTP id r25-20020adfab59000000b001609ddd5579so265701wrc.21 for ; Tue, 12 Oct 2021 13:59:59 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=Exp5E6dmY1PTSyKlOFa3gXPk4wQssFca5mHGxtbGag0=; b=FOtK9RI5Zm+e0PCf4Qf+e2/ZuTm0Las/VhmSiwmSiF9IDMI3IxQda2vnomPgnHEVAc pkBdGz5YBUMcfjTBNjkcvharinOwviHI3QufUwk8cNuxNLaIdAQwvPYXz9HmQlxBY/SM Bv0eqJjB3wOmo1ZQDHYKMHzn8p1GR4VXqWu9YdNrQnNMDCLheaKqvltNFL90knrDBAzx 9aiO/CROn3Pr8qhGVJx6+8be00uSEuADOR0/kAObohys4djRZgG1Rb0ValX2Z/0kFCB7 53yel42vfDdwA8uff0aVw+o9cKsgvxzpVEFcczCC8qldphpPNISuTUN4V9zSbGJEFMQd 0Adg== X-Gm-Message-State: AOAM533E1rqQMVpomvdZAbkqjHFLuBHky1Cykrq7y8z1z20ApnoiXOcu 1BCgx6fDpZTOVqJUcp9id0Ydvqrda5JeQGSN/GP8biwsyNU/goZvw0CgoQBtrCTjXGZZV8+3L+y CCF3imsusela9t35gxGqNVQ== X-Received: by 2002:a05:6000:1289:: with SMTP id f9mr10798867wrx.192.1634072398166; Tue, 12 Oct 2021 13:59:58 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwBCYQfAelhSD7s+gLgNmxS7cksGV+rHTpSwlJhhXjwMp934f0UVw7OkfCfZxHBrxbJpbKA6g== X-Received: by 2002:a05:6000:1289:: with SMTP id f9mr10798853wrx.192.1634072398013; Tue, 12 Oct 2021 13:59:58 -0700 (PDT) Received: from redhat.com ([2.55.159.57]) by smtp.gmail.com with ESMTPSA id 36sm11465676wrc.92.2021.10.12.13.59.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Oct 2021 13:59:57 -0700 (PDT) Date: Tue, 12 Oct 2021 16:59:51 -0400 From: "Michael S. Tsirkin" To: Andi Kleen Cc: Kuppuswamy Sathyanarayanan , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Peter Zijlstra , Andy Lutomirski , Bjorn Helgaas , Richard Henderson , Thomas Bogendoerfer , James E J Bottomley , Helge Deller , "David S . Miller" , Arnd Bergmann , Jonathan Corbet , Paolo Bonzini , David Hildenbrand , Andrea Arcangeli , Josh Poimboeuf , Peter H Anvin , Dave Hansen , Tony Luck , Dan Williams , Kirill Shutemov , Sean Christopherson , Kuppuswamy Sathyanarayanan , x86@kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-alpha@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH v5 16/16] x86/tdx: Add cmdline option to force use of ioremap_host_shared Message-ID: <20211012165705-mutt-send-email-mst@kernel.org> References: <20211009003711.1390019-1-sathyanarayanan.kuppuswamy@linux.intel.com> <20211009003711.1390019-17-sathyanarayanan.kuppuswamy@linux.intel.com> <20211009070132-mutt-send-email-mst@kernel.org> <8c906de6-5efa-b87a-c800-6f07b98339d0@linux.intel.com> <20211011075945-mutt-send-email-mst@kernel.org> <9d0ac556-6a06-0f2e-c4ff-0c3ce742a382@linux.intel.com> <20211011142330-mutt-send-email-mst@kernel.org> <4fe8d60a-2522-f111-995c-dcbefd0d5e31@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4fe8d60a-2522-f111-995c-dcbefd0d5e31@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Tue, Oct 12, 2021 at 10:55:20AM -0700, Andi Kleen wrote: > > > I mean ... it's already wide spread. > > > I meant wide spread usage with confidential guests. > > > If we support it with TDX > > it will be used with TDX. > > It has some security trade offs. The main reason to use TDX is security. > Also when people take the VT-d tradeoffs they might be ok with the BIOS > trade offs too. > > -Andi Interesting. VT-d tradeoffs ... what are they? Allowing hypervisor to write into BIOS looks like it will trivially lead to code execution, won't it? -- MST