diodesign / riscv-sbi-doc

Documentation for the RISC-V Supervisor Binary Interface

RISC-V SBI specification

SBI (Supervisor Binary Interface) is an interface between the Supervisor Execution Environment (SEE) and the supervisor. It allows the supervisor to execute some privileged operations by using the ecall instruction. Examples of SEE and supervisor are: M-Mode and S-Mode on Unix-class platforms, where SBI is the only interface between them, as well as the Hypervisor extended-Supervisor (HS) and Virtualized Supervisor (VS).

Discussion of SBI occurs on the RISC-V Unix Platform Mailing list. It is publicly readable but posting requires being a member of the RISC-V Foundation. Any new SBI extension needs to be discussed and approved there before being merged.

OpenSBI is the reference implementation, but other implementations exist; see section "SBI Implementation IDs".