On Fri, Nov 08, 2019 at 03:44:07PM -0800, Stephen Hemminger wrote: > When I create a virtio-user device with rte_hotplug it creates a kernel > device (ie vtap0). > This is normal an the device has ifindex N. > > But later when device is configured an started the original vtap0 device is > deleted > and a new one is created (with ifindex N+1). This seems like a bug, if > nothing > else it unnecessary overhead and link flapping for routing daemons. > > Noticed only while tracking down a bug where after vtap was created the > address was being set, but then disappearing. > > Is this intentional? Is it documented?
Thanks for catching this. I think it's caused by the fact that tapfds will be closed each time when the queue pairs are disabled [1]. We may need a way to keep tapfds open to fix it. [1] https://github.com/DPDK/dpdk/blob/6bbc5a923625/drivers/net/virtio/virtio_user/vhost_kernel.c#L333-L338 Thanks, Tiwei
