Re: [PATCH v2 2/2] target/riscv: Add step to validate 'B' extension

[Alistair Francis]

On Fri, Jan 12, 2024 at 2:17 AM Rob Bradford <rbradford@rivosinc.com> 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>
> Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  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 5396c6c3eb..b5ba78240e 100644
> --- a/target/riscv/tcg/tcg-cpu.c
> +++ b/target/riscv/tcg/tcg-cpu.c
> @@ -442,6 +442,35 @@ static void riscv_cpu_validate_g(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.
> @@ -455,6 +484,10 @@ void riscv_cpu_validate_set_extensions(RISCVCPU *cpu, 
> Error **errp)
>          riscv_cpu_validate_g(cpu);
>      }
>
> +    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
>
>