Comment 21 for bug 633392

Tais -- we had similar problems to what you describe when trying to share a bonded channel between a host and 1+ guests. Random delays, lost packets, nasty low-level things like MAC addresses appearing for the wrong machine in other hosts' ARP tables.

In the end, we only made it work properly by un-bonding the host adapters (eth0->eth3) and creating a bridge for each of them (br0->br3), and then assigning VMs to bridges explicitly in virt-manager. This seems fine so far, everything is smooth and fast.

Admittedly this is on CentOS 5.4 (KVM 83-164) but I would recommend trying this on any host OS if you're having trouble with a bonded channel.