Fedora 11 guest, using virtio_pci and virtio_net (disk and network). All is working great with guest kernel 2.6.29.4-167.fc11.x86_64. When the 2.6.30.5-43 kernel got pushed, the network stopped working in the guest. I can see it sending out packets, but the guest never receives the responses. I can tell by looking at the dhcpd logs. The packets counts on the host vnetX device AND the counts in the guest are going up on both tx/rx.
*** This bug has been marked as a duplicate of bug 522994 ***