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 039A1C4320A for ; Tue, 24 Aug 2021 01:06:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DCF2361212 for ; Tue, 24 Aug 2021 01:06:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234901AbhHXBGo (ORCPT ); Mon, 23 Aug 2021 21:06:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234724AbhHXBGd (ORCPT ); Mon, 23 Aug 2021 21:06:33 -0400 Received: from mail-pg1-x52b.google.com (mail-pg1-x52b.google.com [IPv6:2607:f8b0:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8324FC061757 for ; Mon, 23 Aug 2021 18:04:11 -0700 (PDT) Received: by mail-pg1-x52b.google.com with SMTP id s11so18263226pgr.11 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=pYGYrvX24n/E5V+adqb943SgaEeBxMJm41/rXH9jwZ81I0io0zY44DVWgFwZLCYWy1 KRuBe7mzNgSLDLJZrkVDfXYuScRAT3nGi2et+Ch6Mp4qv27CQZwvpAU2lKjJ6FRCohsz XwbLNCCzOBOxuszxhSgxJBuqg1Drly6/YIomXpKA7r05RWeNdhCYS3B4T9+vh467YgiU RZ5j8/ervdmnXauJqmCabJEMPQ59KEiFRRQzd+x7rFCoHY2G5FxQ2ZTXf20DEn1W199x 4pw8MqEoNMyw8boRrMRgHcA5gczx81Vt4cA5L58UXI4CuAVnXP5FVFhbQYzalQ3gMY7K ltug== X-Gm-Message-State: AOAM533OTpc4Zfzf3IvrI8Iq3GDtIgW908klQBNzrr+Fvek07JpbKDU7 6IzmJqAKMNjHM1kXAZqLNWU+N5bJD3P4mckvO2FwMg== 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-kernel@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.