[snip]
The security group is configured per VM, the rules are configured by the
system on the node the VM is running on.
>From the user perspective you need to configure a security group policy
and then associate the VM with the relevant policy, there is also a
default policy to which all VMs are associated by default.
To use this feature you need to use the oVirt-Neutron integration -
http://www.ovirt.org/Features/Detailed_OSN_Integration#Security_groups