Virtio_pci Problems

[Steve N]

Dear Experts, 
I set up virtualized environment using Free BSD 9.2 as a guest OS on Linux Hypervisor as a host and attempted to communicate using virtio_pci. 
I have a couple of questions on this environment.
1) I'd like to know the degree of completion of virtio_pci driver. Are any products already offered in markets? If you know an example of some products in the marketplace using virtio_pci working on virtualized Free BSD with Linux hypervisor. 
 2) When I measured a transmission speed under the environment above, I got the results of 904 Mbps for TCP and 327 Mbps for UDP. I'd like to isolate the cause of this issue. I mean this is caused either by my environment or by driver's well-known problem. Have you ever experienced such a case that the performance of UDP is much worse than that of TCP? 
Thank you in advance for your support.