gentoo guest using virtio

kernel config

CONFIG_NET_9P_VIRTIO=m
CONFIG_VIRTIO_BLK=m
CONFIG_VIRTIO_NET=m
CONFIG_VIRTIO_CONSOLE=y
CONFIG_HW_RANDOM_VIRTIO=m
CONFIG_VIRTIO=y
CONFIG_VIRTIO_RING=y
CONFIG_VIRTIO_PCI=y
CONFIG_VIRTIO_BALLOON=m

Virtualization —> 
  Host kernel accelerator for virtio net (EXPERIMENTAL)
<*>   PCI driver for virtio devices (EXPERIMENTAL)
  Virtio balloon driver (EXPERIMENTAL)
Networking Support —>   Plan 9 Resource Sharing Support (9P2000)  —> 
  9P Virtio Transport
Device Drivers  —>  [*] Block devices  —> 
  Virtio block driver (EXPERIMENTAL)
Device Drivers  —>  [*] Network device support  —>
  Virtio network driver (EXPERIMENTAL)
Device Drivers  —>  Character devices  —>
<*> Virtio console
  VirtIO Random Number Generator support

Fedora 16 Virtualizaton setup

yum -y install qemu-kvm libvirt python-virtinst bridge-utils
cat /etc/sysconfig/network-scripts/ifcfg-br0

DEVICE=br0
ONBOOT=yes
TYPE=Bridge
BOOTPROTO=dhcp
STP=on
DELAY=0
NM_CONTROLLED=no

cat /etc/sysconfig/network-scripts/ifcfg-em1
DEVICE=em1
HWADDR=XX:XX:XX:XX:XX:XX
ONBOOT=yes
BRIDGE=br0
TYPE=Ethernet
NM_CONTROLLED=no

systemctl stop NetworkManager.service
systemctl disable NetworkManager.service

chkconfig network on
service network start

reboot