Since I recently saw cloudstack have add this( https://cwiki.apache.org/confluence/display/CLOUDSTACK/GPU+and+vGPU+support+for+CloudStack+Guest+VMs ).
And iGVT( https://01.org/zh/xen/blogs/wangbo85/2014/intel-gvt-gxengt-pubic-release?langredirect=1) is released.
If ovirt add this, it'll be very competitive for ovirt in VDI platforms.