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,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 AEE91C433E0 for ; Wed, 27 Jan 2021 19:56:49 +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 DD03664DA4 for ; Wed, 27 Jan 2021 19:56:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DD03664DA4 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]:52888 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l4qvn-0002Hk-So for qemu-devel@archiver.kernel.org; Wed, 27 Jan 2021 14:56:47 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:55154) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l4quZ-0001MQ-Fq for qemu-devel@nongnu.org; Wed, 27 Jan 2021 14:55:31 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:53166) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l4quW-0007FS-Ds for qemu-devel@nongnu.org; Wed, 27 Jan 2021 14:55:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611777325; 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: in-reply-to:in-reply-to:references:references; bh=3NyW/kZ+56VwfQeBLAaX4Edc8fmHHVBUMfIwCZ9PI8o=; b=OHR22XO8RvjT3B0jvDbV/BRbQvWhDHpvSw2se1w8ymjDZggdomUqblDKLO9PdFlHAlQ7F6 91uENnwduEbbm8AEQ7e9T9QgVar9o9qeNAZz9whDfk85fL/tdUDCkXB+JGGr4dXUlFYnOW RqczwOotzoTFkZs5K1HsCmQNDiFpxI0= 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-317-MhpGmoQFNOWD3P7QtnBzDg-1; Wed, 27 Jan 2021 14:55:21 -0500 X-MC-Unique: MhpGmoQFNOWD3P7QtnBzDg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BAB18101D612; Wed, 27 Jan 2021 19:55:03 +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 1373B6267C; Wed, 27 Jan 2021 19:54:28 +0000 (UTC) Date: Wed, 27 Jan 2021 19:54:25 +0000 From: "Dr. David Alan Gilbert" To: Laszlo Ersek Subject: Re: [PATCH] IOMMU and ATS not supported by vhost-user filesystem. Message-ID: <20210127195425.GQ3052@work-vm> References: <20210127111938.GH299797@stefanha-x1.localdomain> <6e8d0352-8418-ebb4-2562-13d3920093b5@redhat.com> MIME-Version: 1.0 In-Reply-To: <6e8d0352-8418-ebb4-2562-13d3920093b5@redhat.com> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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=us-ascii Content-Disposition: inline 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: Leonardo Garcia , lagarcia@linux.ibm.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" * Laszlo Ersek (lersek@redhat.com) wrote: > On 01/27/21 12:19, 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. > > ... I had the same thought when a few weeks earlier I tried to use > virtio-fs with an SEV guest (just OVMF), and virtiofsd crashed, > apparently :) > > (I didn't report it because, well, SEV wants to prevent sharing between > host and guest, and virtio-fs works precisely in the opposite direction; > so the use case may not have much merit.) Yeh I'm not expecting that to currently work; I can see some uses, but it's much more niche. Dave > Thanks > Laszlo > > > > > 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. > > > > Stefan > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK