Presently platform base addresses used in the Hafnium code are statically defined and provided by the build flow: https://git.trustedfirmware.org/hafnium/project/reference.git/tree/BUILD.gn#n73
There is an ask to mvoe the platform information to the Hypervisor manifest passed by the bootloader for more flexibility:
https://review.trustedfirmware.org/c/hafnium/hafnium/+/8243/comment/0c34f793_fc7d334f/
https://review.trustedfirmware.org/c/hafnium/hafnium/+/9346
The Hypervisor image remains the same but can be reconfigured by adjusting the manifest depending on the platform.