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=-18.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 B6756C43216 for ; Tue, 24 Aug 2021 21:57:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D22C613BD for ; Tue, 24 Aug 2021 21:57:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238629AbhHXV5s (ORCPT ); Tue, 24 Aug 2021 17:57:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40538 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238671AbhHXV5r (ORCPT ); Tue, 24 Aug 2021 17:57:47 -0400 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A4AAC0617A8 for ; Tue, 24 Aug 2021 14:57:02 -0700 (PDT) Received: by mail-pg1-x536.google.com with SMTP id r2so21103481pgl.10 for ; Tue, 24 Aug 2021 14:57:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=JA7HjuVr8UM0YrbUtH7xcK5mGIk2G9+Axy1XWOoFNYg=; b=WsBX54BBkcv11FQPj9OpoaF+eiQb8uX8aKiArIgUDrBIDwtG3b3K65ZX6ebBjitNbN w4lUM9y8oGz/tR3k3Zes2iqrAer9nCavy8Gef4NMWt8VTh8WP99eVbvwz7tkCjz4bHrq vAbZ8Ec6ssdwu8Vug8/ZEHTYcy8EBLuOfy6qwkqNjb6xNwc80u1Guda8rci8qOfunYZ0 tpvzRodESKY7xx/aQWat6XsESTC/QWfHfZ+7nW5YmDN2ExMsidGq069RxDz3mdPWGeXC OP3Af9IIu+FHi8O+HMr5M/iBE1ePbCqYmUUW9YDYLHWdc0H+pZXOSjb/GoYe4tnuXRJP 7sjw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=JA7HjuVr8UM0YrbUtH7xcK5mGIk2G9+Axy1XWOoFNYg=; b=j/PqnzMtylercxjwGQ7DqbQqGzj/0dDJz0o6hNyedUMmzBYAkBXmFKh5xht25HFFW4 c+ggr82ocZSyHpMBchqpIzUIl1RkhnHzcSYJRmp37A5eRYuUx3EqdqYnJYL7chkGaZxC hmAb67SqdPiyBAQeJ4VZwUWk8aR95mXXmSc4RolkV0Z1CTeOqEaB7/xZGnLx5kKRVOK5 SM26FBzWEOql+fBBTY51yq0ZX3/SyeACLgsvPSpiwCgbzEQjxDDUoZEiL0QpCl1ByI0F ZiLBUcQEsxwjB6nXdkKFkvNT5I88PjcrduPC3D5zirLY9S6rVlaT8178irim1sRn2IBj eQ5w== X-Gm-Message-State: AOAM531uSSZ8yJLkcPybQXsViG963ceE5hWdDuVpJqegE9yo4RGRWbNP 5NbkvIa6I6xqYeBiTwhz6mFeNK/qkUBM7sw8AXACEw== X-Google-Smtp-Source: ABdhPJyr0CTHqNS+oxGCjiahAYIwaeoO77gnKnjQxNHphuUI7On2QWYfyaYCmnakkxWh6GLExG3xdOXsxrdjbXSK1NY= X-Received: by 2002:a65:414a:: with SMTP id x10mr26273786pgp.403.1629842221742; Tue, 24 Aug 2021 14:57:01 -0700 (PDT) MIME-Version: 1.0 References: <20210805005218.2912076-1-sathyanarayanan.kuppuswamy@linux.intel.com> <20210805005218.2912076-12-sathyanarayanan.kuppuswamy@linux.intel.com> <20210823195409-mutt-send-email-mst@kernel.org> <26a3cce5-ddf7-cbe6-a41e-58a2aea48f78@linux.intel.com> In-Reply-To: From: Rajat Jain Date: Tue, 24 Aug 2021 14:56:25 -0700 Message-ID: Subject: Re: [PATCH v4 11/15] pci: Add pci_iomap_shared{,_range} To: Dan Williams Cc: "Kuppuswamy, Sathyanarayanan" , "Michael S. Tsirkin" , 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 , Andi Kleen , 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Mon, Aug 23, 2021 at 6:06 PM Dan Williams wrote: > > On Mon, Aug 23, 2021 at 5:31 PM Kuppuswamy, Sathyanarayanan > wrote: > > > > > > > > On 8/23/21 4:56 PM, Michael S. Tsirkin wrote: > > >> Add a new variant of pci_iomap for mapping all PCI resources > > >> of a devices as shared memory with a hypervisor in a confidential > > >> guest. > > >> > > >> Signed-off-by: Andi Kleen > > >> Signed-off-by: Kuppuswamy Sathyanarayanan > > > I'm a bit puzzled by this part. So why should the guest*not* map > > > pci memory as shared? And if the answer is never (as it seems to be) > > > then why not just make regular pci_iomap DTRT? > > > > It is in the context of confidential guest (where VMM is un-trusted). So > > we don't want to make all PCI resource as shared. It should be allowed > > only for hardened drivers/devices. > > That's confusing, isn't device authorization what keeps unaudited > drivers from loading against untrusted devices? I'm feeling like > Michael that this should be a detail that drivers need not care about > explicitly, in which case it does not need to be exported because the > detail can be buried in lower levels. > > Note, I specifically said "unaudited", not "hardened" because as Greg > mentioned the kernel must trust drivers, its devices that may not be > trusted. Can you please point me to the thread where this discussion with Greg is ongoing? Thanks, Rajat