func: target_ulong spapr_rtas_call(sPAPREnvironment *spapr,
                               uint32_t token, uint32_t nargs, target_ulong args,
                               uint32_t nret, target_ulong rets)
  {
      if ((token >= TOKEN_BASE)
          && ((token - TOKEN_BASE) < TOKEN_MAX)) {
          struct rtas_call *call = rtas_table + (token - TOKEN_BASE);
          if (call->fn) {
              call->fn(spapr, token, nargs, args, nret, rets);
      hcall_dprintf("Unknown RTAS token 0x%x\n", token);
      rtas_st(rets, 0, -3);
      return H_PARAMETER;