Description of problem:

Libvirt  doesn't allow you to dynamically attach network interfaces on the RHEL6.0 supplied version of qemu-kvm


Version-Release number of selected component (if applicable):
libvirt  - tested on 0.8.8, code has not changed in 0.9.1 version.
qemu-kvm (0.12.1(qemu-kvm-0.12.1.2)) - version 2:0.12.1.2-2.113.el6_0.8


How reproducible:


Steps to Reproduce:
1. Launch server ('virsh create')
2. Create a bridge network with 'virsh net-create'
3. Attempt to associate bridge with server 
'virsh attach-interface srv-vvh2o network vir0001'


  
Actual results:
error: Failed to attach interface
error: internal error unable to add host net: unknown command: 'host_net_add'

Expected results:

Network should have been hotplugged into virtual server.


Additional info:

Checking the monitor command it looks like the version of qemu on RHEL6 has the 'netdev_add' command not the 'host_net_add' command.

The versioning in the qemu capabilities section of libvirt only activates this feature on qemu versions >= 13. 

RHEL6 qemu-kvm is showing '0.12.1(qemu-kvm-0.12.1.2)'