Re: [PATCH v9 2/5] target/riscv: add riscv-server-ref CPU

[Chao Liu <chao.liu@processmission.com>]

On Thu, Sep 03, 2026 at 03:31:22PM +0800, Daniel Henrique Barboza wrote:
> The harts requirements of RISC-V server platform [1] require RVA23 ISA
> profile support and others.
> 
> We're going for a profile-based implementation, instead of a regular CPU
> that can inherit RVA23, to allow future CPUs to use it internally as a
> starting base for their own extension sets.  There's also a new
> 'rvserver-ref-1.0' flag that can be used to set the extensions in the
> command line for other CPUs, which can be used for testing/debugging
> purposes.
> 
> Note that for all intents and purposes "riscv-server-ref" is a regular
> CPU and no, we're not trying to set a precedent of calling the riscv
> server platform spec a profile.
> 
> [1] defines in rule SEE_020 that we must support at least 11 debug
> triggers (4 for insn address, 4 for insn load/store, 1 for icount,
> one for int, one for excp).  We're going for the minimum.  If more
> triggers are needed users can set any trigger amount with:
> 
> -cpu riscv-server-ref,trigger-count=N
> 
> Note that N must be <= 128.
> 
> [1] https://github.com/riscv-non-isa/riscv-server-platform/blob/main/server_platform_requirements.adoc
> 
> Suggested-by: Icenowy Zheng <uwu@icenowy.me>
> Signed-off-by: Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com>
> Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
> Reviewed-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
Reviewed-by: Chao Liu <chao.liu@processmission.com>

Thanks,
Chao

> ---
>  target/riscv/cpu-qom.h |  1 +
>  target/riscv/cpu.c     | 31 +++++++++++++++++++++++++++++++
>  2 files changed, 32 insertions(+)
> 
> diff --git a/target/riscv/cpu-qom.h b/target/riscv/cpu-qom.h
> index 1a28f1369c..61234842e3 100644
> --- a/target/riscv/cpu-qom.h
> +++ b/target/riscv/cpu-qom.h
> @@ -42,6 +42,7 @@
>  #define TYPE_RISCV_CPU_RVA22S64         RISCV_CPU_TYPE_NAME("rva22s64")
>  #define TYPE_RISCV_CPU_RVA23U64         RISCV_CPU_TYPE_NAME("rva23u64")
>  #define TYPE_RISCV_CPU_RVA23S64         RISCV_CPU_TYPE_NAME("rva23s64")
> +#define TYPE_RISCV_CPU_RVSERVER_REF     RISCV_CPU_TYPE_NAME("riscv-server-ref")
>  #define TYPE_RISCV_CPU_IBEX             RISCV_CPU_TYPE_NAME("lowrisc-ibex")
>  #define TYPE_RISCV_CPU_SHAKTI_C         RISCV_CPU_TYPE_NAME("shakti-c")
>  #define TYPE_RISCV_CPU_SIFIVE_E         RISCV_CPU_TYPE_NAME("sifive-e")
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 4cc73de793..086bc945ba 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -2417,11 +2417,35 @@ static RISCVCPUProfile RVA23S64 = {
>      }
>  };
>  
> +/*
> + * The riscv-server-ref spec isn't a profile per se but its
> + * CPU definition can be modelled as a profile that extends
> + * RVA23, with additional things on top of it, and allowing
> + * future CPUs to derive from it via
> + * ".profile = &RVServerRef1_0;".
> + */
> +static RISCVCPUProfile RVServerRef1_0 = {
> +    .s_parent = &RVA23S64,
> +    .name = "rvserver-ref-1.0",
> +    .satp_mode = VM_1_10_SV48,
> +    .ext_offsets = {
> +        CPU_CFG_OFFSET(ext_zkr),
> +        CPU_CFG_OFFSET(ext_sdtrig),
> +        CPU_CFG_OFFSET(ext_ssaia),
> +        CPU_CFG_OFFSET(ext_ssccfg),
> +        /* ssstrict is always enabled for PRIV_VER_1_12 */
> +
> +        RISCV_PROFILE_EXT_LIST_END
> +    }
> +};
> +
> +
>  RISCVCPUProfile *riscv_profiles[] = {
>      &RVA22U64,
>      &RVA22S64,
>      &RVA23U64,
>      &RVA23S64,
> +    &RVServerRef1_0,
>      NULL,
>  };
>  
> @@ -3757,6 +3781,13 @@ static const TypeInfo riscv_cpu_type_infos[] = {
>  #endif
>      ),
>  
> +    DEFINE_RISCV_CPU(TYPE_RISCV_CPU_RVSERVER_REF, TYPE_RISCV_BARE_CPU,
> +        .profile = &RVServerRef1_0,
> +        .misa_mxl_max = MXL_RV64,
> +        .cfg.max_satp_mode = VM_1_10_SV57,
> +        .num_triggers = 11,
> +    ),
> +
>  #if defined(CONFIG_TCG) && !defined(CONFIG_USER_ONLY)
>      DEFINE_RISCV_CPU(TYPE_RISCV_CPU_BASE128, TYPE_RISCV_DYNAMIC_CPU,
>          .cfg.max_satp_mode = VM_1_10_SV57,
> -- 
> 2.43.0
>