bonding (IEEE 802.3ad) not working with qemu/virtio

As subject says, 802.3ad bonding is not working with virtio network model.

The only errors I see is:

No 802.3ad response from the link partner for any adapters in the bond.

Dumping the network traffic shows that no LACP packets are sent from the
host running with virtio driver, changing to for example e1000 solves
this problem
with no configuration changes.

Is this a known problem?

-- 
Bj(/)rnar