From 283e2c2adcb80148c7f67d71d52134af80d2fbae Mon Sep 17 00:00:00 2001 From: Yuri Benditovich Date: Tue, 13 Dec 2016 10:12:08 +0200 Subject: [PATCH] net: virtio-net discards TX data after link down https://bugzilla.redhat.com/show_bug.cgi?id=1295637 Upon set_link monitor command or upon netdev deletion virtio-net sends link down indication to the guest and stops vhost if one is used. Guest driver can still submit data for TX until it recognizes link loss. If these packets not returned by the host, the Windows guest will never be able to finish disable/removal/shutdown. Now each packet sent by guest after NIC indicated link down will be completed immediately. Signed-off-by: Yuri Benditovich Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/net/virtio-net.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 5009533cfa..6f98eab2ba 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -218,6 +218,14 @@ static void virtio_net_vnet_endian_status(VirtIONet *n, uint8_t status) } } +static void virtio_net_drop_tx_queue_data(VirtIODevice *vdev, VirtQueue *vq) +{ + unsigned int dropped = virtqueue_drop_all(vq); + if (dropped) { + virtio_notify(vdev, vq); + } +} + static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status) { VirtIONet *n = VIRTIO_NET(vdev); @@ -262,6 +270,14 @@ static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status) } else { qemu_bh_cancel(q->tx_bh); } + if ((n->status & VIRTIO_NET_S_LINK_UP) == 0 && + (queue_status & VIRTIO_CONFIG_S_DRIVER_OK)) { + /* if tx is waiting we are likely have some packets in tx queue + * and disabled notification */ + q->tx_waiting = 0; + virtio_queue_set_notification(q->tx_vq, 1); + virtio_net_drop_tx_queue_data(vdev, q->tx_vq); + } } } } @@ -1323,6 +1339,11 @@ static void virtio_net_handle_tx_timer(VirtIODevice *vdev, VirtQueue *vq) VirtIONet *n = VIRTIO_NET(vdev); VirtIONetQueue *q = &n->vqs[vq2q(virtio_get_queue_index(vq))]; + if (unlikely((n->status & VIRTIO_NET_S_LINK_UP) == 0)) { + virtio_net_drop_tx_queue_data(vdev, vq); + return; + } + /* This happens when device was stopped but VCPU wasn't. */ if (!vdev->vm_running) { q->tx_waiting = 1; @@ -1349,6 +1370,11 @@ static void virtio_net_handle_tx_bh(VirtIODevice *vdev, VirtQueue *vq) VirtIONet *n = VIRTIO_NET(vdev); VirtIONetQueue *q = &n->vqs[vq2q(virtio_get_queue_index(vq))]; + if (unlikely((n->status & VIRTIO_NET_S_LINK_UP) == 0)) { + virtio_net_drop_tx_queue_data(vdev, vq); + return; + } + if (unlikely(q->tx_waiting)) { return; } -- 2.11.0