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=-11.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 305D2C76186 for ; Wed, 17 Jul 2019 11:00:52 +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 054D221743 for ; Wed, 17 Jul 2019 11:00:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 054D221743 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]:55894 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hnhg1-0002MG-VQ for qemu-devel@archiver.kernel.org; Wed, 17 Jul 2019 07:00:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35649) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hnhfm-0001qg-Fr for qemu-devel@nongnu.org; Wed, 17 Jul 2019 07:00:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hnhfl-0006tV-6U for qemu-devel@nongnu.org; Wed, 17 Jul 2019 07:00:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55388) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hnhfl-0006mk-0O; Wed, 17 Jul 2019 07:00:33 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 179EB30BD1AD; Wed, 17 Jul 2019 11:00:30 +0000 (UTC) Received: from redhat.com (ovpn-120-247.rdu2.redhat.com [10.10.120.247]) by smtp.corp.redhat.com (Postfix) with SMTP id EAF5B183D7; Wed, 17 Jul 2019 11:00:26 +0000 (UTC) Date: Wed, 17 Jul 2019 07:00:25 -0400 From: "Michael S. Tsirkin" To: Tiwei Bie Message-ID: <20190717065951-mutt-send-email-mst@kernel.org> References: <20190611065137.16329-1-tiwei.bie@intel.com> <20190611085441-mutt-send-email-mst@kernel.org> <20190612021157.GA23850@___> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190612021157.GA23850@___> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Wed, 17 Jul 2019 11:00:30 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [RFC] vhost-user: don't ignore CTRL_VLAN feature 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: jasowang@redhat.com, qemu-devel@nongnu.org, qemu-stable@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Jun 12, 2019 at 10:11:57AM +0800, Tiwei Bie wrote: > On Tue, Jun 11, 2019 at 10:10:14AM -0400, Michael S. Tsirkin wrote: > > On Tue, Jun 11, 2019 at 02:51:37PM +0800, Tiwei Bie wrote: > > > The VIRTIO_NET_F_CTRL_VLAN feature requires the support of > > > vhost-user backend. But it will be advertised to guest driver > > > as long as it's enabled by users in QEMU, while it's not > > > supported by vhost-user backend. This patch fixes this issue. > > > > Fixes by making guest refuse to send vlan tags? > > Fixes by not advertising this feature bit to guest driver > when it's not supported, and guest won't expect the device > to do vlan filtering then. > > > I agree it seems cleaner, but which guests does this actually help? > > > > > Fixes: 72018d1e1917 ("vhost-user: ignore qemu-only features") > > > Cc: qemu-stable@nongnu.org > > > > > > Signed-off-by: Tiwei Bie > > > > A change like that will break migration compatibility, will it not? > > Yeah, that's a problem... > > > Maybe we need to tie it to a machine version somehow... > > > > > > > --- > > > It's not clear in the spec that, whether vlan filtering is > > > also best-effort: > > > https://github.com/oasis-tcs/virtio-spec/blob/37057052e7/content.tex#L3372 > > > > So what breaks if we declare it best effort for now? > > And does it really help if we report that vlan filtering > > is not supported to guests? > > If it's best effort, then it won't violate the spec to > advertise this feature when it's not supported in backends. > OK so it's up to you. Want to propose a spec patch? We already say mac filter is best effort ... > > > > > > > > > hw/net/vhost_net.c | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c > > > index a6b719035c..1444fc9230 100644 > > > --- a/hw/net/vhost_net.c > > > +++ b/hw/net/vhost_net.c > > > @@ -75,6 +75,8 @@ static const int user_feature_bits[] = { > > > VIRTIO_NET_F_MTU, > > > VIRTIO_F_IOMMU_PLATFORM, > > > > > > + VIRTIO_NET_F_CTRL_VLAN, > > > + > > > /* This bit implies RARP isn't sent by QEMU out of band */ > > > VIRTIO_NET_F_GUEST_ANNOUNCE, > > > > > > -- > > > 2.17.1