Xenapp and Xendeskop Cloud Service Grid licenses

If we have an m10 and plan on passing the 4 physical GPU’s through to 4 XenDesktop VM’s. What licenses would we need?

Depends on the OS. For XenApp (Server OS) you would need to have vApps licenses for every user running on RDSH and for XenDesktop (client OS) you would need QvDWS licenses as you want to run Passthrough.