Re: [PATCH 2/3] target/riscv: Add step to validate 'B' extension

[Andrew Jones]

On Tue, Jan 09, 2024 at 05:07:36PM +0000, Rob Bradford wrote:
> If the B extension is enabled warn if the user has disabled any of the
> required extensions that are part of the 'B' extension. Conversely
> enable the extensions that make up the 'B' extension if it is enabled.
> 
> Signed-off-by: Rob Bradford <rbradford@rivosinc.com>
> ---
>  target/riscv/tcg/tcg-cpu.c | 33 +++++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
> 
> diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
> index fda54671d5..f10871d352 100644
> --- a/target/riscv/tcg/tcg-cpu.c
> +++ b/target/riscv/tcg/tcg-cpu.c
> @@ -273,6 +273,35 @@ static void 
> riscv_cpu_disable_priv_spec_isa_exts(RISCVCPU *cpu)
>      }
>  }
>  
> +static void riscv_cpu_validate_b(RISCVCPU *cpu)
> +{
> +    const char *warn_msg = "RVB mandates disabled extension %s";
> +
> +    if (!cpu->cfg.ext_zba) {
> +        if (!cpu_cfg_ext_is_user_set(CPU_CFG_OFFSET(ext_zba))) {
> +            cpu->cfg.ext_zba = true;
> +        } else {
> +            warn_report(warn_msg, "zba");
> +        }
> +    }
> +
> +    if (!cpu->cfg.ext_zbb) {
> +        if (!cpu_cfg_ext_is_user_set(CPU_CFG_OFFSET(ext_zbb))) {
> +            cpu->cfg.ext_zbb = true;
> +        } else {
> +            warn_report(warn_msg, "zbb");
> +        }
> +    }
> +
> +    if (!cpu->cfg.ext_zbs) {
> +        if (!cpu_cfg_ext_is_user_set(CPU_CFG_OFFSET(ext_zbs))) {
> +            cpu->cfg.ext_zbs = true;
> +        } else {
> +            warn_report(warn_msg, "zbs");
> +        }
> +    }
> +}
> +
>  /*
>   * Check consistency between chosen extensions while setting
>   * cpu->cfg accordingly.
> @@ -309,6 +338,10 @@ void riscv_cpu_validate_set_extensions(RISCVCPU *cpu, 
> Error **errp)
>          env->misa_ext_mask |= RVI | RVM | RVA | RVF | RVD;
>      }
>  
> +    if (riscv_has_ext(env, RVB)) {
> +        riscv_cpu_validate_b(cpu);
> +    }
> +
>      if (riscv_has_ext(env, RVI) && riscv_has_ext(env, RVE)) {
>          error_setg(errp,
>                     "I and E extensions are incompatible");
> -- 
> 2.43.0
> 
>

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>