> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c > index 0bbfd7f4574..bc29e118c6d 100644 > --- a/target/riscv/cpu.c > +++ b/target/riscv/cpu.c > @@ -438,6 +438,9 @@ static void riscv_cpu_realize(DeviceState *dev, Error > **errp) > if (cpu->cfg.ext_h) { > target_misa |= RVH; > } > + if (cpu->cfg.ext_b) { > + target_misa |= RVB; > + } > if (cpu->cfg.ext_v) { > target_misa |= RVV; > if (!is_power_of_2(cpu->cfg.vlen)) { > @@ -515,6 +518,7 @@ static Property riscv_cpu_properties[] = { > DEFINE_PROP_BOOL("s", RISCVCPU, cfg.ext_s, true), > DEFINE_PROP_BOOL("u", RISCVCPU, cfg.ext_u, true), > /* This is experimental so mark with 'x-' */ > + DEFINE_PROP_BOOL("x-b", RISCVCPU, cfg.ext_b, true),
I think the default value should be false? > DEFINE_PROP_BOOL("x-h", RISCVCPU, cfg.ext_h, false), > DEFINE_PROP_BOOL("x-v", RISCVCPU, cfg.ext_v, false), > DEFINE_PROP_BOOL("Counters", RISCVCPU, cfg.ext_counters, true),