+static bool virtio_net_started(VirtIONet *n, uint8_t status)
+{
+ return (status & VIRTIO_CONFIG_S_DRIVER_OK) &&
+ (n->status & VIRTIO_NET_S_LINK_UP) && n->vdev.vm_running;
+}
+
+static void virtio_net_vhost_status(VirtIONet *n, uint8_t status)
+{
+ if (!n->nic->nc.peer) {
+ return;
+ }
+ if (n->nic->nc.peer->info->type != NET_CLIENT_TYPE_TAP) {
+ return;
+ }
+
+ if (!tap_get_vhost_net(n->nic->nc.peer)) {
+ return;
+ }
+ if (!!n->vhost_started == virtio_net_started(n, status) &&
+ !n->nic->nc.peer->link_down) {
+ return;
+ }
+ if (!n->vhost_started) {
+ int r;
+ if (!vhost_net_query(tap_get_vhost_net(n->nic->nc.peer), &n->vdev)) {
+ return;
+ }
+ r = vhost_net_start(tap_get_vhost_net(n->nic->nc.peer), &n->vdev);
+ if (r < 0) {
+ error_report("unable to start vhost net: %d: "
+ "falling back on userspace virtio", -r);
+ } else {
+ n->vhost_started = 1;
+ }
+ } else {
+ vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), &n->vdev);
+ n->vhost_started = 0;
+ }
+}
+
+static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status)
+{
+ VirtIONet *n = to_virtio_net(vdev);
+
+ virtio_net_vhost_status(n, status);
+
+ if (!n->tx_waiting) {
+ return;
+ }
+
+ if (virtio_net_started(n, status) && !n->vhost_started) {
+ if (n->tx_timer) {
+ qemu_mod_timer(n->tx_timer,
+ qemu_get_clock_ns(vm_clock) + n->tx_timeout);
+ } else {
+ qemu_bh_schedule(n->tx_bh);
+ }
+ } else {
+ if (n->tx_timer) {
+ qemu_del_timer(n->tx_timer);
+ } else {
+ qemu_bh_cancel(n->tx_bh);
+ }
+ }
+}
+