Enable para-virtualized driver for network/disk in KVM

Here is a manual way to configure para-virtulized driver for network in KVM.

Missing virtio option.

<interface type='bridge'>       <mac address='54:52:00:55:55:37'/>       <source bridge='br0'/>       <target dev='vnet0'/>     </interface>

># virsh shutdown green15
># virsh dumpxml green15 > green15.xml
Edit the green15.xml and add the following line

<interface type='bridge'>       <mac address='54:52:00:55:55:37'/>       <source bridge='br0'/>       <target dev='vnet0'/>       <model type='virtio'/>     </interface>

># virsh define green15.xml
># virsh start green15

Testing
green15># netserver

remote># netperf -H green15 -l 20 -f K


References
1.  KVM, Virt-manager and virtio, http://www.linux-archive.org/fedora-linux-management-tools/192301-kvm-virt-manager-virtio.html
2. Using KVM para-virtualized drivers for existing devices, http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization/form-Virtualization-Installing_the_KVM_Windows_para_virtualized_drivers-Using_KVM_para_virtualized_drivers_for_existing_devices.html
3.