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 AEAABC77B73 for ; Mon, 8 May 2023 06:49:02 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pvufS-0002gn-Ps; Mon, 08 May 2023 02:48:18 -0400 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 1pvufM-0002gP-MR for qemu-devel@nongnu.org; Mon, 08 May 2023 02:48:13 -0400 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 1pvufK-0001mu-Sl for qemu-devel@nongnu.org; Mon, 08 May 2023 02:48:12 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1683528489; 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=8UIowGOW2libFK/uXTL9z04JfKoS9IvWj7U7vHTSq9M=; b=QwGGD/FML7SHUleeyKGLXYQvsBpYUGK2F8SnbFyozZHMJxCgCnWEt0FR9Peg+1BW6jQeTA cyZ4ODfFhuCEctYDJYdGBbkA6h67PSN0JQp+QFaYj5hfjA71sm2jD3ACBobMoT+m8nA/Ie JvXny9n8EtDM1SaDna5IXlMMrwD1kZU= Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-438-YHWfVVjcOEynOUZU62qT4Q-1; Mon, 08 May 2023 02:48:07 -0400 X-MC-Unique: YHWfVVjcOEynOUZU62qT4Q-1 Received: by mail-wm1-f72.google.com with SMTP id 5b1f17b1804b1-3f315735edeso103845535e9.1 for ; Sun, 07 May 2023 23:48:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683528486; x=1686120486; 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=8UIowGOW2libFK/uXTL9z04JfKoS9IvWj7U7vHTSq9M=; b=Z1Nq6aqOigDV+z7rG/tVdHcKn4GzQRHD8og6IR4rlr8XtOyQVqzGkGc2BkAItjkhCt WYahqH+JDVU2Wuon/pIADaA+knFvyMz+SeK+TirHUJQCCk7uh3KHULdzi3R0sYiGreDu zc+MEZ43hd4VccUr7S3louwv9KvDFtog5yXkZye/ITJpywOVGLHDABGHauw2n9Dsyd38 PN3QJZTtAXJZkrGPBpTsslJc0J/NZ81UU9Q1lGtDXedUVSha34V4x32pgNnMPNdNjj5j W/I/CBmaazLzQWtsMfy1bRvqnHMcU5IPECI4X1bKDSeXWY8ceM6bfE9RC0CHwuQWXsaG jGxQ== X-Gm-Message-State: AC+VfDyuT5segydEroRP+sdzbBFdLwLD7ShZOkGOz9kZ/ZGQs7uIFnfx ZQIVbsVo0Ue2A2T57PGaJh/ipb3fVV0aj/5Z1YMZEcnuTQW6dX8k8ZgdL6uviI86bJni5QGN1KI lz2jZlt4MGmakjtY= X-Received: by 2002:a5d:4085:0:b0:307:f75:f581 with SMTP id o5-20020a5d4085000000b003070f75f581mr7323017wrp.18.1683528486192; Sun, 07 May 2023 23:48:06 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ5cO96Jeb+XyAofM9NTIyNBndaQsLceVIb6UOxOFYkq1lTykB7ybXWIEaCvj5uq110fz9c7sg== X-Received: by 2002:a5d:4085:0:b0:307:f75:f581 with SMTP id o5-20020a5d4085000000b003070f75f581mr7323001wrp.18.1683528485858; Sun, 07 May 2023 23:48:05 -0700 (PDT) Received: from redhat.com ([31.187.78.15]) by smtp.gmail.com with ESMTPSA id e1-20020adfdbc1000000b0030795249ffasm2902413wrj.92.2023.05.07.23.48.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 07 May 2023 23:48:05 -0700 (PDT) Date: Mon, 8 May 2023 02:48:01 -0400 From: "Michael S. Tsirkin" To: Jason Wang Cc: Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= , Lei Yang , qemu-devel@nongnu.org Subject: Re: [PATCH] virtio-net: not enable vq reset feature unconditionally Message-ID: <20230508024746-mutt-send-email-mst@kernel.org> References: <20230504101447.389398-1-eperezma@redhat.com> <1683339216.3364966-2-xuanzhuo@linux.alibaba.com> <20230507020037-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, T_SCC_BODY_TEXT_LINE=-0.01 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, May 08, 2023 at 02:44:21PM +0800, Jason Wang wrote: > On Sun, May 7, 2023 at 2:01 PM Michael S. Tsirkin wrote: > > > > On Sat, May 06, 2023 at 10:13:36AM +0800, Xuan Zhuo wrote: > > > On Thu, 4 May 2023 12:14:47 +0200, =?utf-8?q?Eugenio_P=C3=A9rez?= wrote: > > > > The commit 93a97dc5200a ("virtio-net: enable vq reset feature") enables > > > > unconditionally vq reset feature as long as the device is emulated. > > > > This makes impossible to actually disable the feature, and it causes > > > > migration problems from qemu version previous than 7.2. > > > > > > > > The entire final commit is unneeded as device system already enable or > > > > disable the feature properly. > > > > > > > > This reverts commit 93a97dc5200a95e63b99cb625f20b7ae802ba413. > > > > Fixes: 93a97dc5200a ("virtio-net: enable vq reset feature") > > > > Signed-off-by: Eugenio Pérez > > > > > > > > --- > > > > Tested by checking feature bit at /sys/devices/pci.../virtio0/features > > > > enabling and disabling queue_reset virtio-net feature and vhost=on/off > > > > on net device backend. > > > > > > Do you mean that this feature cannot be closed? > > > > > > I tried to close in the guest, it was successful. > > > > > > In addition, in this case, could you try to repair the problem instead of > > > directly revert. > > > > > > Thanks. > > > > What does you patch accomplish though? If it's not needed > > let's not do it. > > It looks to me the unconditional set of this feature breaks the > migration of pre 7.2 machines. > > Also we probably need to make ring_reset as false by default, or > compat it for pre 7.2 machines. > > DEFINE_PROP_BIT64("queue_reset", _state, _field, \ > VIRTIO_F_RING_RESET, true) > > > Thanks Compat I am guessing. Eugenio? > > > > > > --- > > > > hw/net/virtio-net.c | 1 - > > > > 1 file changed, 1 deletion(-) > > > > > > > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > > > > index 53e1c32643..4ea33b6e2e 100644 > > > > --- a/hw/net/virtio-net.c > > > > +++ b/hw/net/virtio-net.c > > > > @@ -805,7 +805,6 @@ static uint64_t virtio_net_get_features(VirtIODevice *vdev, uint64_t features, > > > > } > > > > > > > > if (!get_vhost_net(nc->peer)) { > > > > - virtio_add_feature(&features, VIRTIO_F_RING_RESET); > > > > return features; > > > > } > > > > > > > > -- > > > > 2.31.1 > > > > > >