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 EFC98C4320A for ; Tue, 24 Aug 2021 20:50:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D862F61183 for ; Tue, 24 Aug 2021 20:50:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234033AbhHXUut (ORCPT ); Tue, 24 Aug 2021 16:50:49 -0400 Received: from mga06.intel.com ([134.134.136.31]:34159 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232549AbhHXUus (ORCPT ); Tue, 24 Aug 2021 16:50:48 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10086"; a="278414150" X-IronPort-AV: E=Sophos;i="5.84,348,1620716400"; d="scan'208";a="278414150" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2021 13:50:03 -0700 X-IronPort-AV: E=Sophos;i="5.84,348,1620716400"; d="scan'208";a="526823403" 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 13:50:01 -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: <20210824203115.GA3492097@bjorn-Precision-5520> From: Andi Kleen Message-ID: Date: Tue, 24 Aug 2021 13:50:00 -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: <20210824203115.GA3492097@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: sparclinux@vger.kernel.org On 8/24/2021 1:31 PM, Bjorn Helgaas wrote: > On Tue, Aug 24, 2021 at 01:14:02PM -0700, Andi Kleen wrote: >> 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. > Good material for the commit log next time around. Thanks! This is all in the patch intro too, which should make it into the merge commits. I don't think we can reexplain the basic concepts for every individual patch in a large patch kit. -Andi