We used to busy waiting on the cvq command this tends to be problematic since:
1) CPU could wait for ever on a buggy/malicous device 2) There's no wait to terminate the process that triggers the cvq command So this patch switch to use virtqueue_wait_for_used() to sleep with a timeout (1s) instead of busy polling for the cvq command forever. This gives the scheduler a breath and can let the process can respond to asignal. If the device doesn't respond in the timeout, break the device. Signed-off-by: Jason Wang <[email protected]> --- Changes since V1: - break the device when timeout - get buffer manually since the virtio core check more_used() instead --- drivers/net/virtio_net.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index efd9dd55828b..6a2ea64cfcb5 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -405,6 +405,7 @@ static void disable_rx_mode_work(struct virtnet_info *vi) vi->rx_mode_work_enabled = false; spin_unlock_bh(&vi->rx_mode_lock); + virtqueue_wake_up(vi->cvq); flush_work(&vi->rx_mode_work); } @@ -1497,6 +1498,11 @@ static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq, return !oom; } +static void virtnet_cvq_done(struct virtqueue *cvq) +{ + virtqueue_wake_up(cvq); +} + static void skb_recv_done(struct virtqueue *rvq) { struct virtnet_info *vi = rvq->vdev->priv; @@ -1984,6 +1990,8 @@ static int virtnet_tx_resize(struct virtnet_info *vi, return err; } +static int virtnet_close(struct net_device *dev); + /* * Send command via the control virtqueue and check status. Commands * supported by the hypervisor, as indicated by feature bits, should @@ -2026,14 +2034,14 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd, if (unlikely(!virtqueue_kick(vi->cvq))) return vi->ctrl->status == VIRTIO_NET_OK; - /* Spin for a response, the kick causes an ioport write, trapping - * into the hypervisor, so the request should be handled immediately. - */ - while (!virtqueue_get_buf(vi->cvq, &tmp) && - !virtqueue_is_broken(vi->cvq)) - cpu_relax(); + if (virtqueue_wait_for_used(vi->cvq)) { + virtqueue_get_buf(vi->cvq, &tmp); + return vi->ctrl->status == VIRTIO_NET_OK; + } - return vi->ctrl->status == VIRTIO_NET_OK; + netdev_err(vi->dev, "CVQ command timeout, break the virtio device."); + virtio_break_device(vi->vdev); + return VIRTIO_NET_ERR; } static int virtnet_set_mac_address(struct net_device *dev, void *p) @@ -3526,7 +3534,7 @@ static int virtnet_find_vqs(struct virtnet_info *vi) /* Parameters for control virtqueue, if any */ if (vi->has_cvq) { - callbacks[total_vqs - 1] = NULL; + callbacks[total_vqs - 1] = virtnet_cvq_done; names[total_vqs - 1] = "control"; } -- 2.25.1 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
