2016-08-08 4:19 GMT-07:00 Ilya Maximets <[email protected]>:
> Binding/unbinding of virtio driver inside VM leads to reconfiguration
> of PMD threads. This behaviour may be abused by executing bind/unbind
> in an infinite loop to break normal networking on all ports attached
> to the same instance of Open vSwitch.
>
> Fix that by avoiding reconfiguration if it's not necessary.
> Number of queues will not be decreased to 1 on device disconnection but
> it's not very important in comparison with possible DOS attack from the
> inside of guest OS.
>
>
Makes sense to me
Applied to master, thanks
> Fixes: 81acebdaaf27 ("netdev-dpdk: Obtain number of queues for vhost
> ports from attached virtio.")
> Reported-by: Ciara Loftus <[email protected]>
> Signed-off-by: Ilya Maximets <[email protected]>
> ---
>
> Version 2:
> * Set 'vhost_reconfigured' flag if reconfiguration not
> required.
> * Rebased on current master.
>
> lib/netdev-dpdk.c | 19 +++++++++++--------
> 1 file changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index b671601..ea0e16e 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -2299,10 +2299,17 @@ new_device(int vid)
> newnode = dev->socket_id;
> }
>
> - dev->requested_socket_id = newnode;
> - dev->requested_n_rxq = qp_num;
> - dev->requested_n_txq = qp_num;
> - netdev_request_reconfigure(&dev->up);
> + if (dev->requested_n_txq != qp_num
> + || dev->requested_n_rxq != qp_num
> + || dev->requested_socket_id != newnode) {
> + dev->requested_socket_id = newnode;
> + dev->requested_n_rxq = qp_num;
> + dev->requested_n_txq = qp_num;
> + netdev_request_reconfigure(&dev->up);
> + } else {
> + /* Reconfiguration not required. */
> + dev->vhost_reconfigured = true;
> + }
>
> ovsrcu_index_set(&dev->vid, vid);
> exists = true;
> @@ -2362,11 +2369,7 @@ destroy_device(int vid)
> ovs_mutex_lock(&dev->mutex);
> dev->vhost_reconfigured = false;
> ovsrcu_index_set(&dev->vid, -1);
> - /* Clear tx/rx queue settings. */
> netdev_dpdk_txq_map_clear(dev);
> - dev->requested_n_rxq = NR_QUEUE;
> - dev->requested_n_txq = NR_QUEUE;
> - netdev_request_reconfigure(&dev->up);
>
> netdev_change_seq_changed(&dev->up);
> ovs_mutex_unlock(&dev->mutex);
> --
> 2.7.4
>
> _______________________________________________
> dev mailing list
> [email protected]
> http://openvswitch.org/mailman/listinfo/dev
>
_______________________________________________
dev mailing list
[email protected]
http://openvswitch.org/mailman/listinfo/dev
