Re: [PATCH v11 5/6] target/riscv: Add Smrnmi cpu extension

[Frank Chang]

On Mon, Jan 6, 2025 at 12:15 PM Alistair Francis <alistair23@gmail.com> wrote:

On Tue, Dec 31, 2024 at 1:28 PM <frank.chang@sifive.com> wrote:
>
> From: Tommy Wu <tommy.wu@sifive.com>
>
> This adds the properties for ISA extension Smrnmi.
>
> Also, when Smrnmi is present, the firmware (e.g., OpenSBI) must set
> mnstatus.NMIE to 1 before enabling any interrupts. Otherwise, all
> interrupts will be disabled. Since our current OpenSBI does not
> support Smrnmi yet, let's disable Smrnmi for the 'max' type CPU for
> now. We can re-enable it once OpenSBI includes proper support for it.
>
> Signed-off-by: Frank Chang <frank.chang@sifive.com>
> Signed-off-by: Tommy Wu <tommy.wu@sifive.com>
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> ---
>  target/riscv/cpu.c         | 2 ++
>  target/riscv/tcg/tcg-cpu.c | 6 ++++++
>  2 files changed, 8 insertions(+)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 6c46a2f076..b0d9e93170 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -186,6 +186,7 @@ const RISCVIsaExtData isa_edata_arr[] = {
>      ISA_EXT_DATA_ENTRY(smaia, PRIV_VERSION_1_12_0, ext_smaia),
>      ISA_EXT_DATA_ENTRY(smcntrpmf, PRIV_VERSION_1_12_0, ext_smcntrpmf),
>      ISA_EXT_DATA_ENTRY(smepmp, PRIV_VERSION_1_12_0, ext_smepmp),
> +    ISA_EXT_DATA_ENTRY(smrnmi, PRIV_VERSION_1_12_0, ext_smrnmi),
>      ISA_EXT_DATA_ENTRY(smstateen, PRIV_VERSION_1_12_0, ext_smstateen),
>      ISA_EXT_DATA_ENTRY(ssaia, PRIV_VERSION_1_12_0, ext_ssaia),
>      ISA_EXT_DATA_ENTRY(ssccptr, PRIV_VERSION_1_11_0, has_priv_1_11),
> @@ -1614,6 +1615,7 @@ const RISCVCPUMultiExtConfig riscv_cpu_extensions[] = {
>
>      MULTI_EXT_CFG_BOOL("smaia", ext_smaia, false),
>      MULTI_EXT_CFG_BOOL("smepmp", ext_smepmp, false),
> +    MULTI_EXT_CFG_BOOL("smrnmi", ext_smrnmi, false),
>      MULTI_EXT_CFG_BOOL("smstateen", ext_smstateen, false),
>      MULTI_EXT_CFG_BOOL("ssaia", ext_ssaia, false),
>      MULTI_EXT_CFG_BOOL("svade", ext_svade, false),
> diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
> index cbf2cf1963..c4070c948e 100644
> --- a/target/riscv/tcg/tcg-cpu.c
> +++ b/target/riscv/tcg/tcg-cpu.c
> @@ -1421,6 +1421,12 @@ static void riscv_init_max_cpu_extensions(Object *obj)
>      if (env->misa_mxl != MXL_RV32) {
>          isa_ext_update_enabled(cpu, CPU_CFG_OFFSET(ext_zcf), false);
>      }
> +
> +    /*
> +     * ext_smrnmi requires OpenSBI changes that our current
> +     * image does not have. Disable it for now.
> +     */
> +    isa_ext_update_enabled(cpu, CPU_CFG_OFFSET(ext_smrnmi), false);

Should we log this to users so they know?

Alistair

Sure, I've added it in the v12 patchset.

Regards,

Frank Chang

 

>  }
>
>  static bool riscv_cpu_has_max_extensions(Object *cpu_obj)
> --
> 2.34.1
>
>