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.
Fixes: 81acebdaaf27 ("netdev-dpdk: Obtain number of queues for vhost
ports from attached virtio.")
Reported-by: Ciara Loftus <ciara.lof...@intel.com>
Signed-off-by: Ilya Maximets <i.maxim...@samsung.com>
---
lib/netdev-dpdk.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index a0d541a..98369f1 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -2273,11 +2273,14 @@ new_device(struct virtio_net *virtio_dev)
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);
+ }
ovsrcu_set(&dev->virtio_dev, virtio_dev);
exists = true;
@@ -2333,11 +2336,7 @@ destroy_device(volatile struct virtio_net *virtio_dev)
ovs_mutex_lock(&dev->mutex);
virtio_dev->flags &= ~VIRTIO_DEV_RUNNING;
ovsrcu_set(&dev->virtio_dev, NULL);
- /* 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
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