Just a doubt... is this on a physical infra or is it nested virtualization?
Because in the past I had similar problems I was not able to solve with oVirt hypervisors that were VM in vSphere and had the same problems...
See
http://lists.ovirt.org/pipermail/users/2013-October/016752.html

in my case this happened only using spice as console, while with vnc I was able to access