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=-0.5 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 C90D1C3F2CD for ; Tue, 3 Mar 2020 03:24:01 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8A4D221D56 for ; Tue, 3 Mar 2020 03:24:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="E23py1SZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8A4D221D56 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:41454 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j8yA4-0000Lb-Nl for qemu-devel@archiver.kernel.org; Mon, 02 Mar 2020 22:24:00 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:60702) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j8y9T-0008CO-6P for qemu-devel@nongnu.org; Mon, 02 Mar 2020 22:23:24 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j8y9S-0002OZ-4Z for qemu-devel@nongnu.org; Mon, 02 Mar 2020 22:23:23 -0500 Received: from mail-io1-xd43.google.com ([2607:f8b0:4864:20::d43]:46842) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1j8y9R-0002OR-Uj; Mon, 02 Mar 2020 22:23:22 -0500 Received: by mail-io1-xd43.google.com with SMTP id x21so1892854iox.13; Mon, 02 Mar 2020 19:23:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=0ou9io8uf3VKDbGKlHf2x7eRKMOVTLIyuGgxw2ob+co=; b=E23py1SZEh9w5zXhNH8E8Awsbd5qwG6oheW3LQqnOEgVUE76VOeNhImNk6crl8ycW5 3eXRXgLNRlDwRSMaglEMzQa1Lkjqzzz0elubCIWL5ZkDbNHk2ZH10K5pjdyGQN4L09IY Ux2YetF7NL6R/eHa5EGPrUKeFhQeUL41aGPODZAQ1DMD4F1YDNY8+KNpA+PxMFIgJC07 6qA3W4KG8WlMAI92MEy/ru+Jh4wXKVTeptNEAB6cnNN2ANe9VBl267X43OFYHTJ1G8O3 O1ugo2Y0vC5UWSWrbeU6eSXZgUi8cM2JqVo4TEf6glKPibrrnUfj6xxWpYn/aZtJuCEE gYnw== 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:content-transfer-encoding; bh=0ou9io8uf3VKDbGKlHf2x7eRKMOVTLIyuGgxw2ob+co=; b=nQ4StbkQgMs7gGWi4ubXkWw0426IwIW7tJczJ4Zhi6l55bRjUpoCI1mqaU27PB/uJD oPUN+ytS5q29OmBCi/GRibfts2H33wl1YGi+ZTijj4sDR/yATp6ID60RjXhLrGFyqD7u jOSOmog1A4mGzoBysua88lsj41xKrVpnPme0ioWW8hw2v5+uboieMhRvaLEwG5StE8pe PouH7fieslik4OsIim4iUcX6lSUrklFbl6zrqcpFEqjXl/xOV8eMfIOPKXW9XT4HpNql H6Sl/Vf/6qMu4jiQD8NOAx8CouMh32cHALTNl01ojzMEoZTPbu/HCgWOrGJvsFgZVAwH YQcg== X-Gm-Message-State: ANhLgQ10mGQBsRQYZYUQXXEPu1DdIL8jtL0285UZJQFky5A+33UYyYd8 B45hCG1Yjm+tfGv9lqyHFqrtB0gedCLveebgQe4= X-Google-Smtp-Source: ADFU+vvqDUZ8NzvS7rgMQP3FDX4PFSBnMvSyD3tfYbwvc/9u+ToEgKA0dlyhS9S1GKqSwbTsBRx00T7asjCalrNhy/U= X-Received: by 2002:a5d:80d6:: with SMTP id h22mr2222820ior.129.1583205800885; Mon, 02 Mar 2020 19:23:20 -0800 (PST) MIME-Version: 1.0 References: <20200214132745.23392-1-eric.auger@redhat.com> <20200227111717.GG1645630@redhat.com> <431cb39d-833c-6d02-d7b3-02b3e90446e2@redhat.com> In-Reply-To: <431cb39d-833c-6d02-d7b3-02b3e90446e2@redhat.com> From: Zhangfei Gao Date: Tue, 3 Mar 2020 11:23:10 +0800 Message-ID: Subject: Re: [PATCH v16 00/10] VIRTIO-IOMMU device To: Auger Eric Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::d43 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , kevin.tian@intel.com, =?UTF-8?Q?Daniel_P=2E_Berrang=C3=A9?= , kenneth-lee-2012@foxmail.com, tnowicki@marvell.com, "Michael S. Tsirkin" , quintela@redhat.com, zhangfei.gao@foxmail.com, qemu-devel@nongnu.org, peterx@redhat.com, dgilbert@redhat.com, bharatb.linux@gmail.com, qemu-arm@nongnu.org, "Wangzhou \(B\)" , jean-philippe@linaro.org, eric.auger.pro@gmail.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi Eric On Thu, Feb 27, 2020 at 9:50 PM Auger Eric wrote: > > Hi Daniel, > > On 2/27/20 12:17 PM, Daniel P. Berrang=C3=A9 wrote: > > On Fri, Feb 14, 2020 at 02:27:35PM +0100, Eric Auger wrote: > >> This series implements the QEMU virtio-iommu device. > >> > >> This matches the v0.12 spec (voted) and the corresponding > >> virtio-iommu driver upstreamed in 5.3. All kernel dependencies > >> are resolved for DT integration. The virtio-iommu can be > >> instantiated in ARM virt using: > >> > >> "-device virtio-iommu-pci". > > > > Is there any more documentation besides this ? > > not yet in qemu. > > > > I'm wondering on the intended usage of this, and its relation > > or pros/cons vs other iommu devices > > Maybe if you want to catch up on the topic, looking at the very first > kernel RFC may be a good starting point. Motivation, pros & cons were > discussed in that thread (hey, April 2017!) > https://lists.linuxfoundation.org/pipermail/iommu/2017-April/021217.html > > on ARM we have SMMUv3 emulation. But the VFIO integration is not > possible because SMMU does not have any "caching mode" and my nested > paging kernel series is blocked. So the only solution to integrate with > VFIO is looming virtio-iommu. > > In general the pros that were put forward are: virtio-iommu is > architecture agnostic, removes the burden to accurately model complex > device states, driver can support virtualization specific optimizations > without being constrained by production driver maintenance. Cons is perf > and mem footprint if we do not consider any optimization. > > You can have a look at > > http://events17.linuxfoundation.org/sites/events/files/slides/viommu_arm.= pdf > Thanks for the patches. Could I ask one question? To support vSVA and pasid in guest, which direction you recommend, virtio-iommu or vSMMU (your nested paging) Do we still have any obstacles? Would you mind give some breakdown. Jean mentioned PASID still not supported in QEMU. Thanks