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 E21D7C05027 for ; Sun, 29 Jan 2023 08:13:22 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pM2nZ-0006Tx-2g; Sun, 29 Jan 2023 03:12:25 -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 1pM2nX-0006RV-Kx for qemu-devel@nongnu.org; Sun, 29 Jan 2023 03:12:23 -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 1pM2nU-0005U3-Re for qemu-devel@nongnu.org; Sun, 29 Jan 2023 03:12:23 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674979939; 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=qNE1745vkLKWjAM7tAwtFplyotVikMQs+7jqIb763KM=; b=QVdUqptF/6mAk3Y8OUeFUf0i9/bZX9q3ZH/aEL8kM39bbCsBaZ0JfroNwweq11GE9Ajz64 J9W22UTMCBCWnc698CKJcJt4XTotwgMglwbpI+gc6krNWUxgLoeTHr55bVfdag0Ymagkx0 3fFjM56XqxYz+yDT+a0970wevJoOTD4= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-414-tQf2WJOePbKK6ymGD8r55A-1; Sun, 29 Jan 2023 03:12:17 -0500 X-MC-Unique: tQf2WJOePbKK6ymGD8r55A-1 Received: by mail-wm1-f69.google.com with SMTP id l19-20020a7bc353000000b003dc554c8263so375421wmj.3 for ; Sun, 29 Jan 2023 00:12:16 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to: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=qNE1745vkLKWjAM7tAwtFplyotVikMQs+7jqIb763KM=; b=1ZVgS4Vog8mP/U47fcwEUBeMBSLgW9LcFWBaSYFPVfH/l5x/8nGYXBl/05oS2KBJQj pqHfR2dfrBv1us1lrnfvDlOEidYxghe2qROZEHvFuRkAl+rHdNlWm+elWM8Dh2K+Qzlg HmGk38nwbVOAfWskWtdZVSMrGA1VLTZjcL5a2Y4GzwoabcW8ghilteXFK5BKavco0jy0 a1Qqoq6rhfps7KK0u+qSg5gwfFTBdcbb6RV8/hdxlKiC6uQpqcVHoi6ctdF4vq1bZ0hD s+n3hkbO/1rGPKl9yV2TE2MH9Qys/2mcldOGxVlVsiJBjisQhu2mOHKV2M+8Xs32R1/6 MGJg== X-Gm-Message-State: AFqh2kqQbKdnbukwjJDWUF6bFT2TLqI+ooovuZVEmkBRrMUu8HK9i5Mc hI8QYRYzj/pOlYRAAe8A3J2hP4stDceri/Jh1LqnmwtxL+5/q8lPG2j+wRajR9KPysS7Gtl+b8H q6BVL0Swsvev4J5E= X-Received: by 2002:a05:600c:3ba5:b0:3cf:7925:7a3 with SMTP id n37-20020a05600c3ba500b003cf792507a3mr45587764wms.24.1674979936007; Sun, 29 Jan 2023 00:12:16 -0800 (PST) X-Google-Smtp-Source: AMrXdXtG8LPgFBvzzmiU37MuQl4Wvy5HYbRjqVJYvZClG7oqr4epz5u419d0/2+XUIPqaTcgoJneEQ== X-Received: by 2002:a05:600c:3ba5:b0:3cf:7925:7a3 with SMTP id n37-20020a05600c3ba500b003cf792507a3mr45587747wms.24.1674979935761; Sun, 29 Jan 2023 00:12:15 -0800 (PST) Received: from redhat.com ([2.52.20.248]) by smtp.gmail.com with ESMTPSA id l9-20020a05600c4f0900b003db32ccf4bfsm14368974wmq.41.2023.01.29.00.12.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 29 Jan 2023 00:12:15 -0800 (PST) Date: Sun, 29 Jan 2023 03:12:12 -0500 From: "Michael S. Tsirkin" To: Xuan Zhuo Cc: qemu-devel@nongnu.org, Jason Wang , Alexander Bulekov Subject: Re: [PATCH v1 2/2] virtio-net: virtio_net_flush_tx() check for per-queue reset Message-ID: <20230129025950-mutt-send-email-mst@kernel.org> References: <20230129025150.119972-1-xuanzhuo@linux.alibaba.com> <20230129025150.119972-3-xuanzhuo@linux.alibaba.com> <20230129021402-mutt-send-email-mst@kernel.org> <1674977308.9335406-2-xuanzhuo@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1674977308.9335406-2-xuanzhuo@linux.alibaba.com> 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 Sun, Jan 29, 2023 at 03:28:28PM +0800, Xuan Zhuo wrote: > 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. Hmm maybe. Another idea: isn't virtio_net_tx_complete called with length 0 here? Are there other cases where length is 0? > > 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)) { btw this sounds like you are asking it to reset some state. > > > return num_packets; and then ret = virtio_net_flush_tx(q); if (ret >= n->tx_burst) will reschedule automatically won't it? also why check in virtio_net_flush_tx and not virtio_net_tx_complete? > > > } > > > > > > -- > > > 2.32.0.3.g01195cf9f > >