Keystone has been demonstrated to run on Rocket Chip on FPGAs using FireSim (https://fires.im). There are docs on how to do so here: http://docs.keystone-enclave.org/en/latest/Getting-Started/R...

There's also a branch of BOOM (https://github.com/riscv-boom/riscv-boom/tree/secureboom) that supports Keystone, we're just waiting for it to be merged into master.