[v13,16/26] target/riscv/tcg: validate profiles during finalize

Enabling a profile and then disabling some of its mandatory extensions
is a valid use. It can be useful for debugging and testing. But the
common expected use of enabling a profile is to enable all its mandatory
extensions.

Add an user warning when mandatory extensions from an enabled profile
are disabled in the command line. We're also going to disable the
profile flag in this case since the profile must include all the
mandatory extensions. This flag can be exposed by QMP to indicate the
actual profile state after the CPU is realized.

After this patch, this will throw warnings:

-cpu rv64,rva22u64=true,zihintpause=false,zicbom=false,zicboz=false

qemu-system-riscv64: warning: Profile rva22u64 mandates disabled extension zihintpause
qemu-system-riscv64: warning: Profile rva22u64 mandates disabled extension zicbom
qemu-system-riscv64: warning: Profile rva22u64 mandates disabled extension zicboz

Note that the following will NOT throw warnings because the profile is
being enabled last, hence all its mandatory extensions will be enabled:

-cpu rv64,zihintpause=false,zicbom=false,zicboz=false,rva22u64=true

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
---
 target/riscv/tcg/tcg-cpu.c | 69 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

On Mon, Dec 18, 2023 at 10:57 PM Daniel Henrique Barboza
<dbarboza@ventanamicro.com> wrote:
>
> Enabling a profile and then disabling some of its mandatory extensions
> is a valid use. It can be useful for debugging and testing. But the
> common expected use of enabling a profile is to enable all its mandatory
> extensions.
>
> Add an user warning when mandatory extensions from an enabled profile
> are disabled in the command line. We're also going to disable the
> profile flag in this case since the profile must include all the
> mandatory extensions. This flag can be exposed by QMP to indicate the
> actual profile state after the CPU is realized.
>
> After this patch, this will throw warnings:
>
> -cpu rv64,rva22u64=true,zihintpause=false,zicbom=false,zicboz=false
>
> qemu-system-riscv64: warning: Profile rva22u64 mandates disabled extension zihintpause
> qemu-system-riscv64: warning: Profile rva22u64 mandates disabled extension zicbom
> qemu-system-riscv64: warning: Profile rva22u64 mandates disabled extension zicboz
>
> Note that the following will NOT throw warnings because the profile is
> being enabled last, hence all its mandatory extensions will be enabled:
>
> -cpu rv64,zihintpause=false,zicbom=false,zicboz=false,rva22u64=true
>
> Signed-off-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 | 69 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 69 insertions(+)
>
> diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
> index c9df783c51..005d8be26b 100644
> --- a/target/riscv/tcg/tcg-cpu.c
> +++ b/target/riscv/tcg/tcg-cpu.c
> @@ -147,6 +147,26 @@ static int cpu_cfg_ext_get_min_version(uint32_t ext_offset)
>      g_assert_not_reached();
>  }
>
> +static const char *cpu_cfg_ext_get_name(uint32_t ext_offset)
> +{
> +    const RISCVCPUMultiExtConfig *feat;
> +    const RISCVIsaExtData *edata;
> +
> +    for (edata = isa_edata_arr; edata->name != NULL; edata++) {
> +        if (edata->ext_enable_offset == ext_offset) {
> +            return edata->name;
> +        }
> +    }
> +
> +    for (feat = riscv_cpu_named_features; feat->name != NULL; feat++) {
> +        if (feat->offset == ext_offset) {
> +            return feat->name;
> +        }
> +    }
> +
> +    g_assert_not_reached();
> +}
> +
>  static bool cpu_cfg_offset_is_named_feat(uint32_t ext_offset)
>  {
>      const RISCVCPUMultiExtConfig *feat;
> @@ -727,6 +747,54 @@ void riscv_cpu_validate_set_extensions(RISCVCPU *cpu, Error **errp)
>      riscv_cpu_disable_priv_spec_isa_exts(cpu);
>  }
>
> +static void riscv_cpu_validate_profile(RISCVCPU *cpu,
> +                                       RISCVCPUProfile *profile)
> +{
> +    const char *warn_msg = "Profile %s mandates disabled extension %s";
> +    bool send_warn = profile->user_set && profile->enabled;
> +    bool profile_impl = true;
> +    int i;
> +
> +    for (i = 0; misa_bits[i] != 0; i++) {
> +        uint32_t bit = misa_bits[i];
> +
> +        if (!(profile->misa_ext & bit)) {
> +            continue;
> +        }
> +
> +        if (!riscv_has_ext(&cpu->env, bit)) {
> +            profile_impl = false;
> +
> +            if (send_warn) {
> +                warn_report(warn_msg, profile->name,
> +                            riscv_get_misa_ext_name(bit));
> +            }
> +        }
> +    }
> +
> +    for (i = 0; profile->ext_offsets[i] != RISCV_PROFILE_EXT_LIST_END; i++) {
> +        int ext_offset = profile->ext_offsets[i];
> +
> +        if (!isa_ext_is_enabled(cpu, ext_offset)) {
> +            profile_impl = false;
> +
> +            if (send_warn) {
> +                warn_report(warn_msg, profile->name,
> +                            cpu_cfg_ext_get_name(ext_offset));
> +            }
> +        }
> +    }
> +
> +    profile->enabled = profile_impl;
> +}
> +
> +static void riscv_cpu_validate_profiles(RISCVCPU *cpu)
> +{
> +    for (int i = 0; riscv_profiles[i] != NULL; i++) {
> +        riscv_cpu_validate_profile(cpu, riscv_profiles[i]);
> +    }
> +}
> +
>  void riscv_tcg_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
>  {
>      CPURISCVState *env = &cpu->env;
> @@ -745,6 +813,7 @@ void riscv_tcg_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
>      }
>
>      riscv_cpu_update_named_features(cpu);
> +    riscv_cpu_validate_profiles(cpu);
>
>      if (cpu->cfg.ext_smepmp && !cpu->cfg.pmp) {
>          /*
> --
> 2.43.0
>
>