You will need either LIC-PEFV or LIC-VIA licenses for VIA.
PEFV (not to be confused with PEF) and is to apply role-based firewalling on VPN traffic. It is a per controller license and then allows VIA to be used up to the controller maximum capacity.
With ArubaOS 8 you can use the LIC-VIA license which is a per concurrent connection license.
All available product codes can be found in the VIA Datasheet that is available here.