Nothing new - just highly optimised.
>>>Firecracker is designed to be processor agnostic, though at present it runs only on Intel hardware<<<
That'll be abstraction dependancies then, and will require updates to continue working with newer hardware designs like NT did decades ago but being open source should mean the plug won't be suddenly pulled on any hardware type during a major version update.
Getting VM performance near to that of the bare metal has been the target since the 1970s mainframe VM systems first appeared. If it can keep at 95% with different hardware underpinnings that'll be impressive.