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 B4FB0C433DB for ; Tue, 9 Feb 2021 03:13:57 +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 1C41964E66 for ; Tue, 9 Feb 2021 03:13:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1C41964E66 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]:44862 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l9JTP-0002wM-VU for qemu-devel@archiver.kernel.org; Mon, 08 Feb 2021 22:13:55 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:34182) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l9JSj-0002TC-3E for qemu-devel@nongnu.org; Mon, 08 Feb 2021 22:13:13 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:43013) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l9JSf-0005W6-QZ for qemu-devel@nongnu.org; Mon, 08 Feb 2021 22:13:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612840388; 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=bY09RZMYcKrMEPQlY50zxs9xUAWyTS4OFsVEXUukDlQ=; b=cwwJLpHIla9iRGqStGl1NjVmQKUyPohcwztBn8O57BDOHrDPsVVIR5Sj30EIir4k0TJqYF ns6o1fILBalb1Pysnd9chtTVxRSe1EhvYTM2jtfBE6952iyEAI/RkoAv5J5Wd5KBxr93C3 Grh1vFpC1TEWmK28U/DxMhD4bwGb2sM= 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-14-BmKgnYkNORS9mE_5724PmA-1; Mon, 08 Feb 2021 22:13:06 -0500 X-MC-Unique: BmKgnYkNORS9mE_5724PmA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4C315107ACF5; Tue, 9 Feb 2021 03:13:05 +0000 (UTC) Received: from [10.72.13.32] (ovpn-13-32.pek2.redhat.com [10.72.13.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id 179BB5C626; Tue, 9 Feb 2021 03:12:53 +0000 (UTC) Subject: Re: [PATCH] vhost: Unbreak SMMU and virtio-iommu on dev-iotlb support To: 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: Jason Wang Message-ID: Date: Tue, 9 Feb 2021 11:12:52 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210208183721.GB68242@xz-x1> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Received-SPF: pass client-ip=170.10.133.124; envelope-from=jasowang@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, 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 , Auger Eric , "Michael S . Tsirkin" , qemu-devel@nongnu.org, Eugenio Perez Martin Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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 >