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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id F2B07C4332F for ; Mon, 14 Nov 2022 23:48:14 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ouikC-00050z-Em; Mon, 14 Nov 2022 18:20:05 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ouif4-00039s-Bz for qemu-devel@nongnu.org; Mon, 14 Nov 2022 18:14:42 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oubhL-0005On-G7 for qemu-devel@nongnu.org; Mon, 14 Nov 2022 10:48:36 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668440914; 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=6rRDAFMJJ2qbbt7Hgk5UIr5CQij1ViJUfogyqeC+sdY=; b=IwUcExuJCCyS0cLG1Kmzn3j1XyV61cA5/POWcEffwL0AmMULNEmPuzUYyfeTXisp707WZ7 lCelNUfhEjajIQTr2W9QNzqiItZtxF7nR0yJoXtsUDhUFzpqwoGp8W/1sTKh6XYc5Vo9QO t6ckBP+iwREaZh8K9fxrTx4DgfoStOw= Received: from mail-qt1-f200.google.com (mail-qt1-f200.google.com [209.85.160.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-126-EflcOPqCNh6aIYBTQAaxjg-1; Mon, 14 Nov 2022 10:48:32 -0500 X-MC-Unique: EflcOPqCNh6aIYBTQAaxjg-1 Received: by mail-qt1-f200.google.com with SMTP id ff5-20020a05622a4d8500b003a526107477so8209554qtb.9 for ; Mon, 14 Nov 2022 07:48:32 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=6rRDAFMJJ2qbbt7Hgk5UIr5CQij1ViJUfogyqeC+sdY=; b=ofxDI4wWpfRxzs9PpbNMSBc+zcOMB26hp7yksY7xNRntOmVtQ6e1HsS3S8Mb4wyF88 kcTTLBZHAHDOLfKCkd7tCgIVmbqtFr3qAoMRf79VRQd0cy1DJ8zeCTT9o8Z/+MtEOxyk aOLjAGrsnRf6L2XehmvfGzaBLAllgAx77OP6uE44LjGMTiQl6P0g+dfvIVYIokuTx8Hz H1T2j6C2SCFr9fmNjj3aA7Ro4r32z1lEv/lDYMupHbApmzA7FxGOrFec02guuXQ4QHrK nVql4JzF8VeJAj1thfLYnsZSAoj8HrOGHbro54U8DfjCKj7xOWLi51ZhS7+cgddXUrCS 0xxA== X-Gm-Message-State: ANoB5pnwPBtk0SktjhFLguAS+rVMBi7l9zFvT0Fk2nJ6HkWTNV8zYgfr oGUQ1ugclJmyuscbeDZlnxM3tn0ry8s5oLV5E0uos85ca35zxM1FuJVYVvrZulTffR9219vKz+p j/QP+8dLca2t+2cg= X-Received: by 2002:a05:622a:98e:b0:3a5:122:fbe4 with SMTP id bw14-20020a05622a098e00b003a50122fbe4mr12881462qtb.493.1668440911801; Mon, 14 Nov 2022 07:48:31 -0800 (PST) X-Google-Smtp-Source: AA0mqf5te+JHJLwH9KaIF/LyiS9a9m+kwlwG/8+j+4Ct78dwg8FyapmF0goSyGhi25GWxasgm5EN7A== X-Received: by 2002:a05:622a:98e:b0:3a5:122:fbe4 with SMTP id bw14-20020a05622a098e00b003a50122fbe4mr12881443qtb.493.1668440911487; Mon, 14 Nov 2022 07:48:31 -0800 (PST) Received: from redhat.com ([37.19.196.93]) by smtp.gmail.com with ESMTPSA id t8-20020a37ea08000000b006fa313bf185sm6739867qkj.8.2022.11.14.07.48.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Nov 2022 07:48:30 -0800 (PST) Date: Mon, 14 Nov 2022 10:48:26 -0500 From: "Michael S. Tsirkin" To: Hyman Cc: qemu-devel , Jason Wang , Stefano Garzarella , Raphael Norwitz , Guoyi Tu , =?iso-8859-1?Q?Marc-Andr=E9?= Lureau Subject: Re: [PATCH v3 2/2] vhost-net: Fix the virtio features negotiation flaw Message-ID: <20221114104008-mutt-send-email-mst@kernel.org> References: <2560bb4e8cabc550da07162c520aff3669a8f56f.1667136717.git.huangy81@chinatelecom.cn> <20221110141415-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Received-SPF: pass client-ip=170.10.133.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, Nov 14, 2022 at 11:35:30PM +0800, Hyman wrote: > > > 在 2022/11/11 3:17, Michael S. Tsirkin 写道: > > On Sun, Oct 30, 2022 at 09:52:39PM +0800, huangy81@chinatelecom.cn wrote: > > > From: Hyman Huang(黄勇) > > > > > > Save the acked_features once it be configured by guest > > > virtio driver so it can't miss any features. > > > > > > Note that this patch also change the features saving logic > > > in chr_closed_bh, which originally backup features no matter > > > whether the features are 0 or not, but now do it only if > > > features aren't 0. > > > > > > As to reset acked_features to 0 if needed, Qemu always > > > keeping the backup acked_features up-to-date, and save the > > > acked_features after virtio_net_set_features in advance, > > > including reset acked_features to 0, so the behavior is > > > also covered. > > > > > > Signed-off-by: Hyman Huang(黄勇) > > > Signed-off-by: Guoyi Tu > > > --- > > > hw/net/vhost_net.c | 9 +++++++++ > > > hw/net/virtio-net.c | 5 +++++ > > > include/net/vhost_net.h | 2 ++ > > > net/vhost-user.c | 6 +----- > > > 4 files changed, 17 insertions(+), 5 deletions(-) > > > > > > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c > > > index d28f8b9..2bffc27 100644 > > > --- a/hw/net/vhost_net.c > > > +++ b/hw/net/vhost_net.c > > > @@ -141,6 +141,15 @@ uint64_t vhost_net_get_acked_features(VHostNetState *net) > > > return net->dev.acked_features; > > > } > > > +void vhost_net_save_acked_features(NetClientState *nc) > > > +{ > > > + if (nc->info->type != NET_CLIENT_DRIVER_VHOST_USER) { > > > + return; > > > + } > > > + > > > + vhost_user_save_acked_features(nc, false); > > > +} > > > + > > > static int vhost_net_get_fd(NetClientState *backend) > > > { > > > switch (backend->info->type) { > > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > > > index e9f696b..5f8f788 100644 > > > --- a/hw/net/virtio-net.c > > > +++ b/hw/net/virtio-net.c > > > @@ -924,6 +924,11 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) > > > continue; > > > } > > > vhost_net_ack_features(get_vhost_net(nc->peer), features); > > > + /* > > > + * keep acked_features in NetVhostUserState up-to-date so it > > > + * can't miss any features configured by guest virtio driver. > > > + */ > > > + vhost_net_save_acked_features(nc->peer); > > > } > > > if (virtio_has_feature(features, VIRTIO_NET_F_CTRL_VLAN)) { > > > > So when do you want to ack features but *not* save them? > When openvswitch restart and reconnect and Qemu start the vhost_dev， > acked_features in vhost_dev Qemu need to be initialized and the initialized > value be fetched from acked_features int NetVhostUserState. > At this time, acked_features may not be up-to-date but we want it. > > > > Is the effect of this patch, fundamentally, that guest features > > from virtio are always copied to vhost-user? > > Do we even need an extra copy in vhost user then? > > > I'm trying to explain this from my view, please point out the mistake if i > failed. :) > > When socket used by vhost-user device disconnectted from openvswitch, > Qemu will stop the vhost-user and clean up the whole struct of > vhost_dev(include vm's memory region and acked_features), once socket is > reconnected from openvswitch, Qemu will collect vm's memory region > dynamically but as to acked_features, IMHO, Qemu can not fetch it from guest > features of virtio-net, because acked_features are kind of different from > guest features(bit 30 is different at least)，so Qemu need an extra copy. Well we already have a list of valid frontend features in user_feature_bits. > > > > all this came in with: > > > > commit a463215b087c41d7ca94e51aa347cde523831873 > > Author: Marc-André Lureau > > Date: Mon Jun 6 18:45:05 2016 +0200 > > > > vhost-net: save & restore vhost-user acked features > > > > Marc-André do you remember why we have a copy of features in vhost-user > > and not just reuse the features from virtio? > > > > > > > diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h > > > index 387e913..3a5579b 100644 > > > --- a/include/net/vhost_net.h > > > +++ b/include/net/vhost_net.h > > > @@ -46,6 +46,8 @@ int vhost_set_vring_enable(NetClientState * nc, int enable); > > > uint64_t vhost_net_get_acked_features(VHostNetState *net); > > > +void vhost_net_save_acked_features(NetClientState *nc); > > > + > > > int vhost_net_set_mtu(struct vhost_net *net, uint16_t mtu); > > > #endif > > > diff --git a/net/vhost-user.c b/net/vhost-user.c > > > index 74f349c..c512cc9 100644 > > > --- a/net/vhost-user.c > > > +++ b/net/vhost-user.c > > > @@ -258,11 +258,7 @@ static void chr_closed_bh(void *opaque) > > > s = DO_UPCAST(NetVhostUserState, nc, ncs[0]); > > > for (i = queues -1; i >= 0; i--) { > > > - s = DO_UPCAST(NetVhostUserState, nc, ncs[i]); > > > - > > > - if (s->vhost_net) { > > > - s->acked_features = vhost_net_get_acked_features(s->vhost_net); > > > - } > > > + vhost_user_save_acked_features(ncs[i], false); > > > } > > > qmp_set_link(name, false, &err); > > > -- > > > 1.8.3.1 > >