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 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 a signal. Signed-off-by: Jason Wang <[email protected]> --- drivers/net/virtio_net.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 8225496ccb1e..69173049371f 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; @@ -2024,12 +2030,7 @@ 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(); + virtqueue_wait_for_used(vi->cvq, &tmp); return vi->ctrl->status == VIRTIO_NET_OK; } @@ -3524,7 +3525,7 @@ 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
