Brendan Gregg's blog describes the Xen virtualiization modes quite well.
http://www.brendangregg.com/blog/2014-05-07/what-color-is-your-xen.html
I've just updated to OVS 3.4.1 and it looks to me like it is Xen 4.4 based.
So if I install an OL7 VM with UEK R4 (Linux kernel mainline version 4.1.12) and convert it to boot as PVM guest am I now running with all 4 virtualization features green?