Re: [PATCH v13 3/7] target/riscv: Add helper functions to calculate current number of masked bits for pointer masking

[Alistair Francis]

On Mon, Dec 16, 2024 at 10:19 PM <baturo.alexey@gmail.com> wrote:
>
> From: Alexey Baturo <baturo.alexey@gmail.com>
>
> Signed-off-by: Alexey Baturo <baturo.alexey@gmail.com>
> ---
>  target/riscv/cpu.h        |  5 +++
>  target/riscv/cpu_helper.c | 73 +++++++++++++++++++++++++++++++++++++++
>  2 files changed, 78 insertions(+)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 417ff45544..e7f346ff6b 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -768,8 +768,13 @@ void cpu_get_tb_cpu_state(CPURISCVState *env, vaddr *pc,
>
>  bool riscv_cpu_is_32bit(RISCVCPU *cpu);
>
> +bool riscv_cpu_virt_mem_enabled(CPURISCVState *env);
> +RISCVPmPmm riscv_pm_get_pmm(CPURISCVState *env);
> +uint32_t riscv_pm_get_pmlen(RISCVPmPmm pmm);
> +
>  RISCVException riscv_csrr(CPURISCVState *env, int csrno,
>                            target_ulong *ret_value);
> +
>  RISCVException riscv_csrrw(CPURISCVState *env, int csrno,
>                             target_ulong *ret_value,
>                             target_ulong new_value, target_ulong write_mask);
> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> index dba04851d5..ed0d275e84 100644
> --- a/target/riscv/cpu_helper.c
> +++ b/target/riscv/cpu_helper.c
> @@ -214,6 +214,79 @@ void cpu_get_tb_cpu_state(CPURISCVState *env, vaddr *pc,
>      *pflags = flags;
>  }
>
> +RISCVPmPmm riscv_pm_get_pmm(CPURISCVState *env)
> +{
> +    RISCVPmPmm pmm = PMM_FIELD_DISABLED;
> +#ifndef CONFIG_USER_ONLY
> +    if (get_field(env->mstatus, MSTATUS_MPRV) &&
> +        get_field(env->mstatus, MSTATUS_MXR)) {
> +        return pmm;
> +    }
> +    int priv_mode = cpu_address_mode(env);

QEMU style is to not mix code and declarations.

I think a clearer way would be

#ifndef CONFIG_USER_ONLY
    RISCVPmPmm pmm = PMM_FIELD_DISABLED;
    int priv_mode = cpu_address_mode(env);

    if (get_field(env->mstatus, MSTATUS_MPRV) &&
        get_field(env->mstatus, MSTATUS_MXR)) {
        return pmm;
    }

    /* Get current PMM field */
...
    return pmm;
#else
    return PMM_FIELD_DISABLED;
#endif


> +    /* Get current PMM field */
> +    switch (priv_mode) {
> +    case PRV_M:
> +        if (riscv_cpu_cfg(env)->ext_smmpm) {
> +            pmm = get_field(env->mseccfg, MSECCFG_PMM);
> +        }
> +        break;
> +    case PRV_S:
> +        if (riscv_cpu_cfg(env)->ext_smnpm) {
> +            if (get_field(env->mstatus, MSTATUS_MPV)) {
> +                pmm = get_field(env->henvcfg, HENVCFG_PMM);
> +            } else {
> +                pmm = get_field(env->menvcfg, MENVCFG_PMM);
> +            }
> +        }
> +        break;
> +    case PRV_U:
> +        if (riscv_has_ext(env, RVS)) {
> +            if (riscv_cpu_cfg(env)->ext_ssnpm) {
> +                pmm = get_field(env->senvcfg, SENVCFG_PMM);
> +            }
> +        } else {
> +            if (riscv_cpu_cfg(env)->ext_smnpm) {
> +                pmm = get_field(env->menvcfg, MENVCFG_PMM);
> +            }
> +        }
> +        break;
> +    default:
> +        g_assert_not_reached();
> +    }
> +#endif
> +    return pmm;
> +}
> +
> +bool riscv_cpu_virt_mem_enabled(CPURISCVState *env)
> +{
> +    bool virt_mem_en = false;
> +#ifndef CONFIG_USER_ONLY
> +    int satp_mode = 0;
> +    int priv_mode = cpu_address_mode(env);

New line please :)

> +    if (riscv_cpu_mxl(env) == MXL_RV32) {
> +        satp_mode = get_field(env->satp, SATP32_MODE);
> +    } else {
> +        satp_mode = get_field(env->satp, SATP64_MODE);
> +    }
> +    virt_mem_en = ((satp_mode != VM_1_10_MBARE) && (priv_mode != PRV_M));
> +#endif
> +    return virt_mem_en;

I think an #else is probably easier to read

Otherwise:

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

Alistair

> +}
> +
> +uint32_t riscv_pm_get_pmlen(RISCVPmPmm pmm)
> +{
> +    switch (pmm) {
> +    case PMM_FIELD_DISABLED:
> +        return 0;
> +    case PMM_FIELD_PMLEN7:
> +        return 7;
> +    case PMM_FIELD_PMLEN16:
> +        return 16;
> +    default:
> +        g_assert_not_reached();
> +    }
> +}
> +
>  #ifndef CONFIG_USER_ONLY
>
>  /*
> --
> 2.39.5
>