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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 E413EC07E95 for ; Wed, 7 Jul 2021 09:32:22 +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 88DF761C6C for ; Wed, 7 Jul 2021 09:32:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 88DF761C6C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:57894 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m13un-0008Rx-OB for qemu-devel@archiver.kernel.org; Wed, 07 Jul 2021 05:32:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39156) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m13sT-0004nb-SX for qemu-devel@nongnu.org; Wed, 07 Jul 2021 05:29:57 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:45732) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m13sQ-00033N-Cc for qemu-devel@nongnu.org; Wed, 07 Jul 2021 05:29:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625650192; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=o/bIJN5glXqepYvCWXhd5RxhIEtcIYzdGPJaBAh9hJM=; b=SAA8NscMB0mJ4XtbLNa4Q0x725jYOVUBr2hgZyRSt4ktF8SVvpWcFL0XED4V11XvGL3W/i npOMEYKbGkeZMWBcUu1qsQ+SNNiBqYVP8fQkpfjntftgANeWPZ+Ijn1KUN6+L814pkBAIM pJlLNzyrbA3r4pIYzn8MR99xmhrJp4o= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-144-waaPjcaXPr6aGsa1aRYYPA-1; Wed, 07 Jul 2021 05:29:50 -0400 X-MC-Unique: waaPjcaXPr6aGsa1aRYYPA-1 Received: by mail-wr1-f69.google.com with SMTP id u7-20020a5d46870000b029012786ba1bc9so545841wrq.21 for ; Wed, 07 Jul 2021 02:29:50 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=o/bIJN5glXqepYvCWXhd5RxhIEtcIYzdGPJaBAh9hJM=; b=CcDa1yIApQQhdxJNBdWAWVFVWl7UMy6yITX4pe1H+27Kwnu/PEqVusJ1ezoTpoO55a JLyXcuVDNGnmz+Buk9d7t/QhABhHSqOfyxB1V//ZkXpOhfXwUId9jN7qLwRfzX2Jp9ZV hw0oQOH6pIMI5aSVEUfWPlUsQqIUo669TLm/CYzgeNR9RpYRfRfBxY/DU2Isj/speqgU vW/DU+dG29ncV1Iu44Gp+k5XXCeB7rkgy2V1YVu4o7snKwwURDpasYcKF5KTY5VxO6Oo cVj5FY8qVforIvz8S3nGmp586MvtBXU6Imb8y4rPagBK1cPGnaVg5nFYFNuhfKimM0/k 9SSQ== X-Gm-Message-State: AOAM533qXVRY1FHN+4xH0jmztYHsLPo8rwzhfaPxyiASclfi//vYDOCU 5a5xjoaGm356FsJClaSlexrqzNMzeBgc9pX+0DiWUnUoGbq2zIH4obOZgVBbwafShkOqRbWmTdb lU+z5iKKxvuOxLYM= X-Received: by 2002:a05:6000:180b:: with SMTP id m11mr9124704wrh.6.1625650189312; Wed, 07 Jul 2021 02:29:49 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzQ7E3fKtYtjVyWmbzwOFYApPJSZqdHjqKiZEy33FWVnYWkt6WUxHWGz27U/K1ZYiEwGz5OiA== X-Received: by 2002:a05:6000:180b:: with SMTP id m11mr9124696wrh.6.1625650189160; Wed, 07 Jul 2021 02:29:49 -0700 (PDT) Received: from ?IPv6:2a01:e0a:59e:9d80:527b:9dff:feef:3874? ([2a01:e0a:59e:9d80:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id m5sm5260712wmq.2.2021.07.07.02.29.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 07 Jul 2021 02:29:48 -0700 (PDT) Subject: Re: [PATCH] docs: Add '-device intel-iommu' entry To: Peter Xu , qemu-devel@nongnu.org References: <20210611185500.343525-1-peterx@redhat.com> From: Eric Auger Message-ID: <6355528a-5d67-f178-90f9-53103d7540f1@redhat.com> Date: Wed, 7 Jul 2021 11:29:47 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210611185500.343525-1-peterx@redhat.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eauger@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=eauger@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.442, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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: "Michael S . Tsirkin" , Jason Wang , Alex Williamson , Lei Yang , Jing Zhao , Chao Yang Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi Peter, On 6/11/21 8:55 PM, Peter Xu wrote: > The parameters of intel-iommu device are non-trivial to understand. Add an > entry for it so that people can reference to it when using. > > There're actually a few more options there, but I hide them explicitly because > they shouldn't be used by normal QEMU users. > > Cc: Chao Yang > Cc: Lei Yang > Cc: Jing Zhao > Cc: Jason Wang > Cc: Michael S. Tsirkin > Cc: Alex Williamson > Signed-off-by: Peter Xu > --- > qemu-options.hx | 32 ++++++++++++++++++++++++++++++++ > 1 file changed, 32 insertions(+) > > diff --git a/qemu-options.hx b/qemu-options.hx > index 14258784b3a..4bb04243907 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -926,6 +926,38 @@ SRST > > ``-device pci-ipmi-bt,bmc=id`` > Like the KCS interface, but defines a BT interface on the PCI bus. > + > +``-device intel-iommu[,option=...]`` > + This is only supported by ``-machine q35``, which will enable Intel VT-d > + emulation within the guest. It supports below options: > + > + ``intremap=on|off`` (default: auto) > + This enables interrupt remapping feature in the guest. It's required > + to enable complete x2apic. Currently it only supports kvm > + kernel-irqchip modes ``off`` or ``split``. Full kernel-irqchip is not > + yet supported. maybe explain how the default is chosen (based on kernel-irqhcip mode?) > + > + ``caching-mode=on|off`` (default: off) > + This enables caching mode for the VT-d emulated device. When > + caching-mode is enabled, each guest DMA buffer mapping will generate an > + IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in > + a synchronous way. It is required for ``-device vfio-pci`` to work > + with the VT-d device, because host assigned devices requires to setup > + the DMA mapping on the host before guest DMA starts. > + > + ``device-iotlb=on|off`` (default: off) > + This enables device-iotlb capability for the emulated VT-d device. So > + far virtio/vhost should be the only real user for this parameter, I thought if was needed for vhost. What is the usage for virtio? > + paired with ats=on configured for the device. What is not obvious to me is whether there is a kind of diagnosis whether device-iotlb and caching mode settings are consistent with vfio/vhost usage. Does qemu exit if there is inconsistency? > + > + ``aw-bits=39|48`` (default: 39) > + This decides the address width of IOVA address space. The address > + space has 39 bits width for 3-level IOMMU page tables, and 48 bits for > + 4-level IOMMU page tables. > + > + Please also refer to the wiki page for general scenarios of VT-d > + emulation in QEMU: https://wiki.qemu.org/Features/VT-d. > + > ERST > > DEF("name", HAS_ARG, QEMU_OPTION_name, > Besides, it is quite useful. Thanks Eric