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From: | Kangjie Xu |
Subject: | Re: [PATCH v3 13/15] virtio-net: support queue reset |
Date: | Tue, 6 Sep 2022 11:14:17 +0800 |
User-agent: | Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.13.0 |
在 2022/9/5 16:30, Jason Wang 写道:
在 2022/8/25 16:08, Kangjie Xu 写道:From: Xuan Zhuo <xuanzhuo@linux.alibaba.com> virtio-net and vhost-kernel implement queue reset. Queued packets in the corresponding queue pair are flushed or purged. Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com> --- hw/net/virtio-net.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 27b59c0ad6..d774a3e652 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c@@ -540,6 +540,23 @@ static RxFilterInfo *virtio_net_query_rxfilter(NetClientState *nc)return info; }+static void virtio_net_queue_reset(VirtIODevice *vdev, uint32_t queue_index)+{ + VirtIONet *n = VIRTIO_NET(vdev); + NetClientState *nc = qemu_get_subqueue(n->nic, vq2q(queue_index)); + + if (!nc->peer) { + return; + } + + if (get_vhost_net(nc->peer) && + nc->peer->info->type == NET_CLIENT_DRIVER_TAP) { + vhost_net_virtqueue_reset(vdev, nc, queue_index); + } + + flush_or_purge_queued_packets(nc);But the codes doesn't prevent the usersapce datapath from being used? (e.g vhost=off)
I think we do not need to prevent it for vhost=off, because the virtio-net device is in control of the tap device.
After we reset the vq, the virtio-net send and recv will not use the userspace datapath. (virtio_net_flush_tx() and virtio_net_receive() will early returns because vq->vring.avail == 0)
So even if we don't prevent it using net->nc->info->poll, virtio-net device will prevent it. And the logic here is similar to virtio_reset(), I think it will not cause problems.
Thanks.
E.g vhost_net_start_one() had: if (net->nc->info->poll) { net->nc->info->poll(net->nc, false); } And I will wonder if it's better to consider to:1) factor out the per virtqueue start/stop from vhost_net_start/stop_one()2) simply use the helper factored out via step 1) Thanks+} + static void virtio_net_reset(VirtIODevice *vdev) { VirtIONet *n = VIRTIO_NET(vdev);@@ -3784,6 +3801,7 @@ static void virtio_net_class_init(ObjectClass *klass, void *data)vdc->set_features = virtio_net_set_features; vdc->bad_features = virtio_net_bad_features; vdc->reset = virtio_net_reset; + vdc->queue_reset = virtio_net_queue_reset; vdc->set_status = virtio_net_set_status; vdc->guest_notifier_mask = virtio_net_guest_notifier_mask; vdc->guest_notifier_pending = virtio_net_guest_notifier_pending;
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