I am not sure how to test DXVA but HDCP was an issue because I wasn't able to get the qemu emulated device to go away without crashing/hanging my VM. Xen 4.2 has lots of patches that may make it work better but this is still the unstable version and no pre-built packages exist.
To get WMC to pass my system for Digital Cable Advisor I found a .cmd file online that tricked it.
I wasn't able to test video playback on this VM with WMC because this computer has no audio card. If you look at my motherboard, it is a straight server board, my intention was alway to get a headless HTPC setup that can stream to my extenders.
My RAID is handled by my Areca hardware RAID controller, the way it works is in it's BIOS I define volume sets that are exposed to the computers BIOS as physical disks. The OS just needs a driver which Linux has. The guest OS has some paravirtualized drivers for accessing the space I provision for it.
