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 4E5F3C05027 for ; Sun, 29 Jan 2023 07:36:39 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pM2Eg-0006dO-9Q; Sun, 29 Jan 2023 02:36:22 -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 1pM2Eb-0006d8-OX for qemu-devel@nongnu.org; Sun, 29 Jan 2023 02:36:18 -0500 Received: from out30-57.freemail.mail.aliyun.com ([115.124.30.57]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pM2EX-0000Jw-VD for qemu-devel@nongnu.org; Sun, 29 Jan 2023 02:36:16 -0500 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R101e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=ay29a033018045170; MF=xuanzhuo@linux.alibaba.com; NM=1; PH=DS; RN=4; SR=0; TI=SMTPD_---0VaJivYM_1674977761; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0VaJivYM_1674977761) by smtp.aliyun-inc.com; Sun, 29 Jan 2023 15:36:02 +0800 Message-ID: <1674977308.9335406-2-xuanzhuo@linux.alibaba.com> Subject: Re: [PATCH v1 2/2] virtio-net: virtio_net_flush_tx() check for per-queue reset Date: Sun, 29 Jan 2023 15:28:28 +0800 From: Xuan Zhuo To: "Michael S. Tsirkin" Cc: qemu-devel@nongnu.org, Jason Wang , Alexander Bulekov References: <20230129025150.119972-1-xuanzhuo@linux.alibaba.com> <20230129025150.119972-3-xuanzhuo@linux.alibaba.com> <20230129021402-mutt-send-email-mst@kernel.org> In-Reply-To: <20230129021402-mutt-send-email-mst@kernel.org> Received-SPF: pass client-ip=115.124.30.57; envelope-from=xuanzhuo@linux.alibaba.com; helo=out30-57.freemail.mail.aliyun.com X-Spam_score_int: -98 X-Spam_score: -9.9 X-Spam_bar: --------- X-Spam_report: (-9.9 / 5.0 requ) BAYES_00=-1.9, ENV_AND_HDR_SPF_MATCH=-0.5, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, UNPARSEABLE_RELAY=0.001, USER_IN_DEF_SPF_WL=-7.5 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 Sun, 29 Jan 2023 02:25:43 -0500, "Michael S. Tsirkin" wrote: > On Sun, Jan 29, 2023 at 10:51:50AM +0800, Xuan Zhuo wrote: > > Check whether it is per-queue reset state in virtio_net_flush_tx(). > > > > Before per-queue reset, we need to recover async tx resources. At this > > time, virtio_net_flush_tx() is called, but we should not try to send > > new packets, so virtio_net_flush_tx() should check the current > > per-queue reset state. > > > What does "at this time" mean here? > Do you in fact mean it's called from flush_or_purge_queued_packets? Yes virtio_queue_reset k->queue_reset virtio_net_queue_reset flush_or_purge_queued_packets qemu_flush_or_purge_queued_packets ..... (callback) virtio_net_tx_complete virtio_net_flush_tx <-- here send new packet. We need stop it. Because it is inside the callback, I can't pass information through the stack. I originally thought it was a general situation, so I wanted to put it in struct VirtQueue. If it is not very suitable, it may be better to put it in VirtIONetQueue. Thanks. > What does the call stack look like? > > If yes introducing a vq state just so virtio_net_flush_tx > knows we are in the process of reset would be a bad idea. > We want something much more local, ideally on stack even ... > > > > > > Fixes: 7dc6be52 ("virtio-net: support queue reset") > > Fixes: https://gitlab.com/qemu-project/qemu/-/issues/1451 > > Reported-by: Alexander Bulekov > > Signed-off-by: Xuan Zhuo > > --- > > hw/net/virtio-net.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > > index 3ae909041a..fba6451a50 100644 > > --- a/hw/net/virtio-net.c > > +++ b/hw/net/virtio-net.c > > @@ -2627,7 +2627,8 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) > > VirtQueueElement *elem; > > int32_t num_packets = 0; > > int queue_index = vq2q(virtio_get_queue_index(q->tx_vq)); > > - if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) { > > + if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) || > > + virtio_queue_reset_state(q->tx_vq)) { > > return num_packets; > > } > > > > -- > > 2.32.0.3.g01195cf9f >