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=-17.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,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 68EF5C433DB for ; Wed, 27 Jan 2021 19:41:44 +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 B448164D9E for ; Wed, 27 Jan 2021 19:41:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B448164D9E 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]:42828 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l4qhC-0005gY-BW for qemu-devel@archiver.kernel.org; Wed, 27 Jan 2021 14:41:42 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:52912) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l4qg6-0005AN-Bs for qemu-devel@nongnu.org; Wed, 27 Jan 2021 14:40:34 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:35644) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l4qg4-0005d1-Im for qemu-devel@nongnu.org; Wed, 27 Jan 2021 14:40:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611776431; 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=7PjP3hCnpGd9zGIMphwG3n7XqFGbBrJ7+lmgJQTZ8TM=; b=XZuyYcF3/daUUHo6SpErbm75k7nIHgf9gNXTact9t5x0woy8QfoU0w4xqewJO8AOXJAGi5 d8YaCUw44Xg9m7iqFTEt2wNpZKcLMnf1cj9RuRxRCwcANRt5OxTj6aNBVObKj+uuSlLfa8 CLg9px6QpqsrC1RRV8H7UREPbMEKgUk= 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-401-1kraMN7SMKuzbLekq-mU1Q-1; Wed, 27 Jan 2021 14:40:29 -0500 X-MC-Unique: 1kraMN7SMKuzbLekq-mU1Q-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A86C3806674; Wed, 27 Jan 2021 19:40:28 +0000 (UTC) Received: from work-vm (ovpn-115-50.ams2.redhat.com [10.36.115.50]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9FA1817C5F; Wed, 27 Jan 2021 19:40:18 +0000 (UTC) Date: Wed, 27 Jan 2021 19:40:16 +0000 From: "Dr. David Alan Gilbert" To: Leonardo Augusto =?iso-8859-1?Q?Guimar=E3es?= Garcia Subject: Re: [PATCH] IOMMU and ATS not supported by vhost-user filesystem. Message-ID: <20210127194016.GP3052@work-vm> References: <20210127111938.GH299797@stefanha-x1.localdomain> <20210127163423.GI3052@work-vm> <3b31eb9a-1737-e681-73a1-e4a96313a819@br.ibm.com> MIME-Version: 1.0 In-Reply-To: <3b31eb9a-1737-e681-73a1-e4a96313a819@br.ibm.com> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.308, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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: maxime.coquelin@redhat.com, qemu-devel@nongnu.org, Stefan Hajnoczi , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Leonardo Augusto Guimarães Garcia (lagarcia@br.ibm.com) wrote: > On 1/27/21 1:34 PM, Dr. David Alan Gilbert wrote: > > * Leonardo Augusto Guimarães Garcia (lagarcia@linux.ibm.com) wrote: > > > On 1/27/21 8:19 AM, Stefan Hajnoczi wrote: > > > > On Tue, Jan 26, 2021 at 03:23:38PM -0300, lagarcia@linux.ibm.com wrote: > > > > > From: Leonardo Garcia > > > > > > > > > > Currently, as IOMMU and ATS are not supported, if a user mistakenly set > > > > > any of them and tries to mount the vhost-user filesystem inside the > > > > > guest, whenever the user tries to access the mount point, the system > > > > > will hang forever. > > > > > > > > > > Signed-off-by: Leonardo Garcia > > > > > --- > > > > > hw/virtio/vhost-user-fs-pci.c | 7 +++++++ > > > > > hw/virtio/vhost-user-fs.c | 5 +++++ > > > > > 2 files changed, 12 insertions(+) > > > > > > > > > > diff --git a/hw/virtio/vhost-user-fs-pci.c b/hw/virtio/vhost-user-fs-pci.c > > > > > index 2ed8492b3f..564d1fd108 100644 > > > > > --- a/hw/virtio/vhost-user-fs-pci.c > > > > > +++ b/hw/virtio/vhost-user-fs-pci.c > > > > > @@ -11,6 +11,8 @@ > > > > > * top-level directory. > > > > > */ > > > > > +#include "qemu/osdep.h" > > > > > +#include "qapi/error.h" > > > > > #include "qemu/osdep.h" > > > > > #include "hw/qdev-properties.h" > > > > > #include "hw/virtio/vhost-user-fs.h" > > > > > @@ -45,6 +47,11 @@ static void vhost_user_fs_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp) > > > > > vpci_dev->nvectors = dev->vdev.conf.num_request_queues + 2; > > > > > } > > > > > + if (vpci_dev->flags & VIRTIO_PCI_FLAG_ATS) { > > > > > + error_setg(errp, "ATS is currently not supported with vhost-user-fs-pci"); > > > > > + return; > > > > > + } > > > > Why is this check needed in addition to VIRTIO_F_IOMMU_PLATFORM? > > > > > > > > What needs to be added to support ATS? > > > > > > > > > + > > > > > qdev_realize(vdev, BUS(&vpci_dev->bus), errp); > > > > > } > > > > > diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c > > > > > index ac4fc34b36..914d68b3ee 100644 > > > > > --- a/hw/virtio/vhost-user-fs.c > > > > > +++ b/hw/virtio/vhost-user-fs.c > > > > > @@ -203,6 +203,11 @@ static void vuf_device_realize(DeviceState *dev, Error **errp) > > > > > return; > > > > > } > > > > > + if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) { > > > > > + error_setg(errp, "IOMMU is currently not supported with vhost-user-fs"); > > > > > + return; > > > > > + } > > > > > + > > > > > if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) { > > > > I thought IOMMU support depends on the vhost-user device backend (e.g. > > > > virtiofsd), so the vhost-user backend should participate in advertising > > > > this feature. > > > > > > > > Perhaps the check should be: > > > > > > > > ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user, > > > > VHOST_BACKEND_TYPE_USER, 0); > > > > if (ret < 0) { > > > > error_setg_errno(errp, -ret, "vhost_dev_init failed"); > > > > goto err_virtio; > > > > } > > > > + > > > > + if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM) && > > > > + !(fs->vhost_dev.hdev_features & (1ull << VIRTIO_F_IOMMU_PLATFORM))) { > > > > + error_setg(errp, "IOMMU is not supported by the vhost-user device backend"); > > > > + goto err_iommu_needed; > > > > + } > > > > > > > > Also, can this logic be made generic for all vhost-user devices? It's > > > > not really specific to vhost-user-fs. > > > Further analyzing this, on vhost-user.c, I see: > > > > > >         if (virtio_has_feature(features, VIRTIO_F_IOMMU_PLATFORM) && > > >                 !(virtio_has_feature(dev->protocol_features, > > >                     VHOST_USER_PROTOCOL_F_SLAVE_REQ) && > > >                  virtio_has_feature(dev->protocol_features, > > >                     VHOST_USER_PROTOCOL_F_REPLY_ACK))) { > > >             error_report("IOMMU support requires reply-ack and " > > >                          "slave-req protocol features."); > > >             return -1; > > >         } > > > > > > This code was included by commit 6dcdd06. It included support for > > > VIRTIO_F_IOMMU_PLATFORM with vhost_net devices. So, the restriction is not > > > generic for all vhost-user devices. > > That test is a slightly different test; that's checking that the > > vhost-user device has two underlying features that are needed to make > > iommu work; it's not a full test though; it doesn't actually check the > > vhost-user device also wants to do iommu. > > > Right... but Stefan was suggesting to move the check I proposed to avoid > VIRTIO_F_IOMMU_PLATFORM on vhost-user-fs up to vhost-user. What I understand > from the above code excerpt and the rest of commit 6dcdd06 is that IOMMU > support has been added into vhost-user already. However, it seems > vhost-user-fs (maybe all other devices on top of vhost-user) doesn't support > it yet. If I move the check up to vhost-user, does it make sense to still > have all the IOMMU code support there? Libvhost-user isn't just used by virtiofs; so it can have IOMMU code in (I'm not convinced it was complete though); it just needs to make sure that the device is also happy to do IOMMU, as Stefan's code did. Dave > Leo > > > > > > Dave > > > > > Cheers, > > > > > > Leo > > > > > > > Stefan > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK