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=-6.6 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 0EC8DC43216 for ; Tue, 24 Aug 2021 20:14:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E9F3861040 for ; Tue, 24 Aug 2021 20:14:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234927AbhHXUOw (ORCPT ); Tue, 24 Aug 2021 16:14:52 -0400 Received: from mga03.intel.com ([134.134.136.65]:27696 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232099AbhHXUOv (ORCPT ); Tue, 24 Aug 2021 16:14:51 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10086"; a="217426630" X-IronPort-AV: E=Sophos;i="5.84,348,1620716400"; d="scan'208";a="217426630" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2021 13:14:05 -0700 X-IronPort-AV: E=Sophos;i="5.84,348,1620716400"; d="scan'208";a="526813111" Received: from akleen-mobl1.amr.corp.intel.com (HELO [10.209.119.65]) ([10.209.119.65]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2021 13:14:03 -0700 Subject: Re: [PATCH v4 11/15] pci: Add pci_iomap_shared{,_range} To: Bjorn Helgaas Cc: "Michael S. Tsirkin" , Dan Williams , "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 , Peter H Anvin , Dave Hansen , Tony Luck , Kirill Shutemov , Sean Christopherson , Kuppuswamy Sathyanarayanan , X86 ML , Linux Kernel Mailing List , Linux PCI , linux-alpha@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch , Linux Doc Mailing List , virtualization@lists.linux-foundation.org, Rajat Jain References: <20210824185541.GA3485816@bjorn-Precision-5520> From: Andi Kleen Message-ID: Date: Tue, 24 Aug 2021 13:14:02 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20210824185541.GA3485816@bjorn-Precision-5520> 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-pci@vger.kernel.org On 8/24/2021 11:55 AM, Bjorn Helgaas wrote: > [+cc Rajat; I still don't know what "shared memory with a hypervisor > in a confidential guest" means, A confidential guest is a guest which uses memory encryption to isolate itself from the host. It doesn't trust the host. But it still needs to communicate with the host for IO, so it has some special memory areas that are explicitly marked shared. These are used to do IO with the host. All their usage needs to be carefully hardened to avoid any security attacks on the guest, that's why we want to limit this interaction only to a small set of hardened drivers. For MMIO, the set is currently only virtio and MSI-X. -Andi