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=-5.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 85C39C433E6 for ; Tue, 9 Feb 2021 17:18:07 +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 AEBFE64EC0 for ; Tue, 9 Feb 2021 17:18:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AEBFE64EC0 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]:51590 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l9WeL-00083a-6f for qemu-devel@archiver.kernel.org; Tue, 09 Feb 2021 12:18:05 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:50330) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l9Wbo-0006Ed-LV for qemu-devel@nongnu.org; Tue, 09 Feb 2021 12:15:28 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:56951) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l9Wbm-0000rw-EK for qemu-devel@nongnu.org; Tue, 09 Feb 2021 12:15:28 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612890924; 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=yDINSqIp06Pa2Pej+CRkQzLBe2rvC74g4AVYWv3dcwI=; b=Qkh9RxFGcEFepI4b16h9lOo0sHio7nOzITDxQoFWNolIeYJGDfINwKhndVh0ZduGbdfGH2 7K+7Xplx6fFK1U6W7D2i2IhoXyiH5MWG1OCcR8njKesqPH57y/7GvAf5VuLXZuW6p6XrTF YHIPluYD5QCaEhKApYNKIG/c7E/Ik9o= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-595-DPFTTSCdN46NAzqYqrGjfA-1; Tue, 09 Feb 2021 12:15:22 -0500 X-MC-Unique: DPFTTSCdN46NAzqYqrGjfA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5A3861087D69; Tue, 9 Feb 2021 17:15:21 +0000 (UTC) Received: from [10.36.112.10] (ovpn-112-10.ams2.redhat.com [10.36.112.10]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 881C160C4D; Tue, 9 Feb 2021 17:15:13 +0000 (UTC) Subject: Re: [PATCH] vhost: Unbreak SMMU and virtio-iommu on dev-iotlb support To: Jason Wang , Peter Xu References: <20210204191228.187550-1-peterx@redhat.com> <2382a93d-41c1-24fd-144f-87ee18171bc9@redhat.com> <213acf9a-d1c0-3a1d-4846-877d90fadc03@redhat.com> <20210205153107.GX6468@xz-x1> <20210208183721.GB68242@xz-x1> From: Auger Eric Message-ID: <6ddf3db5-552a-4984-5f52-836178e5f486@redhat.com> Date: Tue, 9 Feb 2021 18:15:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eric.auger@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: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=eric.auger@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -35 X-Spam_score: -3.6 X-Spam_bar: --- X-Spam_report: (-3.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.57, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.265, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=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: Jean-Philippe Brucker , Eugenio Perez Martin , qemu-devel@nongnu.org, "Michael S . Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi, On 2/9/21 4:12 AM, Jason Wang wrote: > > On 2021/2/9 上午2:37, Peter Xu wrote: >> On Mon, Feb 08, 2021 at 11:21:23AM +0800, Jason Wang wrote: >> >> [...] >> >>>> I'm not sure I remember it right, but we seem to have similar >>>> discussion >>>> previously on "what if the user didn't specify ats=on" - I think at >>>> that time >>>> the conclusion was that we ignore the failure since that's not a valid >>>> configuration for qemu. >>> >>> Yes, but I think I was wrong at that time. >> I can't say you're wrong - I actually still agree with you that at least >> there's a priority of things we'd do, and this one is not extremely >> important >> if that's not a major use case (say, if you will 100% always suggest >> an user to >> use ats=on for a viommu enabled vhost). > > > Right, but it depends on e.g how libvirt use that. As far as I know, > they do enable ATS. But it would still an issue if libvirt want to > support vIOMMUs other than intel. > > >> >>>> The other issue I'm worried is (I think I mentioned it somewhere, >>>> but just to >>>> double confirm): I'd like to make sure SMMU and virtio-iommu are the >>>> only IOMMU >>>> platform that will use vhost. >>> >>> For upstream, it won't be easy :) >> Sorry I definitely didn't make myself clear... :) >> >> To be explicit, does ppc use vhost kernel too? > > > I think the answer is yes. > > >>   Since I know at least ppc has >> its own translation unit and its iommu notifier in qemu, so I'm unsure >> whether >> the same patch would break ppc too, because vhost could also ignore >> all UNMAP >> sent by the ppc vIOMMU. > > > If this is true, we probably need to fix that. > > >> >>> >>>>     Otherwise IIUC we need to fix those vIOMMUs too. >>> >>> Right, last time I check AMD IOMMU emulation, it simply trigger >>> device IOTLB >>> invalidation during IOTLB invalidation which looks wrong. >> I did quickly grep IOMMU_NOTIFIER_UNMAP in amd_iommu.c and saw >> nothing. It >> seems amd iommu is not ready for any kind of IOMMU notifiers yet. >> >> Thanks, > > > Right. > > Thanks > > >> > > I just noted that the vhost fix now breaks virtio-iommu/vfio integration because VFIO registers IOMMU_NOTIFIER_ALL which includes the DEV-IOTLB that is now rejected by virtio-iommu virtio_iommu_notify_flag_changed(). Is it safe to replace IOMMU_NOTIFIER_ALL by IOMMU_NOTIFIER_IOTLB_EVENTS in vfio_listener_region_add (hw/vfio/common.c) or shall we also do the 2-step registration? After your confirmation, I can send the patch. Thanks Eric