Re: [PATCH v4 1/6] target/riscv: Add cfg property for SiFive int8 matmul extensions

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

On Sun, Sep 27, 2026 at 04:25:29PM +0800, Max Chou wrote:
> Add the CPU config properties for SiFive's custom int8 matrix
> multiply vector extensions:
> 
> - Xsfvqmaccdod: 2x8x2 int8 matrix-multiply-accumulate operations
> - Xsfvqmaccqoq: 4x8x4 int8 matrix-multiply-accumulate operations
> 
> All instructions of these extensions require the Zve32x extension
> to be present whenever either extension is enabled. Validate this
> in riscv_cpu_validate_vendor_ext() alongside the existing vector
> extension validation in riscv_cpu_validate_set_extensions().
> 
> Reviewed-by: Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com>
> Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
> Signed-off-by: Max Chou <max.chou@sifive.com>
Reviewed-by: Chao Liu <chao.liu@processmission.com>

Thanks,
Chao

> ---
>  target/riscv/cpu.c                |  2 ++
>  target/riscv/cpu_cfg_fields.h.inc |  2 ++
>  target/riscv/tcg/tcg-cpu.c        | 16 ++++++++++++++++
>  3 files changed, 20 insertions(+)
> 
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index da4c1a090b9..55833896bef 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -299,6 +299,8 @@ const RISCVIsaExtData isa_edata_arr[] = {
>      ISA_EXT_DATA_ENTRY(xmipscbop, PRIV_VERSION_1_12_0, ext_xmipscbop),
>      ISA_EXT_DATA_ENTRY(xmipscmov, PRIV_VERSION_1_12_0, ext_xmipscmov),
>      ISA_EXT_DATA_ENTRY(xmipslsp, PRIV_VERSION_1_12_0, ext_xmipslsp),
> +    ISA_EXT_DATA_ENTRY(xsfvqmaccdod, PRIV_VERSION_1_13_0, ext_xsfvqmaccdod),
> +    ISA_EXT_DATA_ENTRY(xsfvqmaccqoq, PRIV_VERSION_1_13_0, ext_xsfvqmaccqoq),
>      ISA_EXT_DATA_ENTRY(xtheadba, PRIV_VERSION_1_11_0, ext_xtheadba),
>      ISA_EXT_DATA_ENTRY(xtheadbb, PRIV_VERSION_1_11_0, ext_xtheadbb),
>      ISA_EXT_DATA_ENTRY(xtheadbs, PRIV_VERSION_1_11_0, ext_xtheadbs),
> diff --git a/target/riscv/cpu_cfg_fields.h.inc b/target/riscv/cpu_cfg_fields.h.inc
> index f91c780299c..0f3bda1331c 100644
> --- a/target/riscv/cpu_cfg_fields.h.inc
> +++ b/target/riscv/cpu_cfg_fields.h.inc
> @@ -159,6 +159,8 @@ BOOL_FIELD(ext_xmipscbop)
>  BOOL_FIELD(ext_xmipscmov)
>  BOOL_FIELD(ext_xmipslsp)
>  BOOL_FIELD(ext_xlrbr)
> +BOOL_FIELD(ext_xsfvqmaccdod)
> +BOOL_FIELD(ext_xsfvqmaccqoq)
>  
>  BOOL_FIELD(big_endian)
>  BOOL_FIELD(mmu)
> diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
> index b68160af830..4f132488b9e 100644
> --- a/target/riscv/tcg/tcg-cpu.c
> +++ b/target/riscv/tcg/tcg-cpu.c
> @@ -416,6 +416,16 @@ static void riscv_cpu_validate_v(CPURISCVState *env, RISCVCPUConfig *cfg,
>      }
>  }
>  
> +static void riscv_cpu_validate_vendor_ext(RISCVCPU *cpu, Error **errp)
> +{
> +    if ((cpu->cfg.ext_xsfvqmaccdod || cpu->cfg.ext_xsfvqmaccqoq) &&
> +        !cpu->cfg.ext_zve32x) {
> +        error_setg(errp, "Xsfvqmaccdod/Xsfvqmaccqoq extensions require "
> +                         "Zve32x extension");
> +        return;
> +    }
> +}
> +
>  static void riscv_cpu_disable_priv_spec_isa_exts(RISCVCPU *cpu)
>  {
>      CPURISCVState *env = &cpu->env;
> @@ -793,6 +803,12 @@ void riscv_cpu_validate_set_extensions(RISCVCPU *cpu, Error **errp)
>          return;
>      }
>  
> +    riscv_cpu_validate_vendor_ext(cpu, &local_err);
> +    if (local_err != NULL) {
> +        error_propagate(errp, local_err);
> +        return;
> +    }
> +
>      if (mcc->def->misa_mxl_max == MXL_RV32 && cpu->cfg.ext_svukte) {
>          error_setg(errp, "svukte is not supported for RV32");
>          return;
> -- 
> 2.43.0
>