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=-8.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 90C74C4338F for ; Tue, 24 Aug 2021 01:06:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A73F60E8B for ; Tue, 24 Aug 2021 01:06:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234973AbhHXBGm (ORCPT ); Mon, 23 Aug 2021 21:06:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234722AbhHXBGd (ORCPT ); Mon, 23 Aug 2021 21:06:33 -0400 Received: from mail-pg1-x52e.google.com (mail-pg1-x52e.google.com [IPv6:2607:f8b0:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8268CC061575 for ; Mon, 23 Aug 2021 18:04:11 -0700 (PDT) Received: by mail-pg1-x52e.google.com with SMTP id n18so18267554pgm.12 for ; Mon, 23 Aug 2021 18:04:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=+KWjXh2lT4oyxvT6TUUge6cE2M/3E1/QPatrdIWAbCk=; b=ssDUJbZQUoHOjzKeOoupouQflaDtoV/KGM0ZbImx65Id9YAIXzBr7xLGKgTJu5h7I2 HHPWAyYNY1bDMlXgvnD4vDkqa1dsykDsMeTtzg3vHCZHA743vpTJ8zJ4NdfqSdbmmqvy KiEWa7Khi9N0O/9RoziHtutYHO2/nwyh6DBm4tBUK7GNpef0LXqDL+0p5s3nrsgMW6K/ FFWm8o5SonyxAvLyA2+U5fUS7ZWjvbxn5iMEzqko5Bo0H+b6KX6dRPsNpkxsT+0zJzz9 wV+DeBmwuvYfrQWDLM0QASdRWxoXpFfTwLTHLiDMsXuWjkskMss7fMermWEKgv/FmCUr IxMA== 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=+KWjXh2lT4oyxvT6TUUge6cE2M/3E1/QPatrdIWAbCk=; b=a2GCqw+V/vZK5d+QXawlvE33gFivs1X08KG1VHrd62Q0jaAeleo4adsAacDz4OSgBN zRbS259f+WvF7jv3ilck/S8zQJgYhGfDcQ8DkA9aUoHZHxs07se3eB2veDbYpnm+D8jn arucpnZtUij9aRj6XkSE7tgiJ7vZ7JMuepR8/4cs7vyQRRNlbO3uczUeTptypI3NRSay Rt32VIHoJYQ/20Z15+vJjMwOB/vY+9O1B8uWad1eTvd8drXsaTvNAnbSe3+hUniC4Fuk gnLKg5/tg6XkHSJcpQECjC4HlIchrT8EmamlgwuJxBDv6lYCojmXW8ivIkaYAZ/G0qg7 mLWA== X-Gm-Message-State: AOAM533f5DVB/f0Nu2Exj1VDz95QUmJvXPgqzoK/HmB26hx4yxV3vhiX 8jbnInE6aTzBaFEOSJ3gRnSLDrMDVEuwEjhiNR9fag== X-Google-Smtp-Source: ABdhPJwr+d+03lWZE5hBC3RKJQrz+BrvZKJ9PwHrCLpkrlXplyqx0kAfavOgC5QFY0A8k9yCeP+k8gHn1t12t0fKZcY= X-Received: by 2002:a05:6a00:16c6:b029:32d:e190:9dd0 with SMTP id l6-20020a056a0016c6b029032de1909dd0mr36118105pfc.70.1629767051049; Mon, 23 Aug 2021 18:04:11 -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: <26a3cce5-ddf7-cbe6-a41e-58a2aea48f78@linux.intel.com> From: Dan Williams Date: Mon, 23 Aug 2021 18:04:00 -0700 Message-ID: Subject: Re: [PATCH v4 11/15] pci: Add pci_iomap_shared{,_range} To: "Kuppuswamy, Sathyanarayanan" Cc: "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 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.