The RISC-V Server Platform specification defines a standardized set of hardware and sofware capabilities, that portable system software, such as operating systems and hypervisors, can rely on being present in a RISC-V server platform.
Server SoC spec will have items that are consistent with the platform security spec, so whatever added to server platform should look to server soc as the base.
See discussion in https://github.com/riscv-non-isa/riscv-brs/issues/135.