Re: [PATCH 3/5] RISC-V: KVM: Allow bfloat16 extension for Guest/VM

[Nutty Liu]

On 6/17/2025 9:10 PM, zhouquan@xxxxxxxxxxx wrote:
> From: Quan Zhou <zhouquan@xxxxxxxxxxx>
>
> Extend the KVM ISA extension ONE_REG interface to allow KVM user space
> to detect and enable Zfbmin/Zvfbfmin/Zvfbfwma extension for Guest/VM.
>
> Signed-off-by: Quan Zhou <zhouquan@xxxxxxxxxxx>
> ---
>   arch/riscv/include/uapi/asm/kvm.h | 3 +++
>   arch/riscv/kvm/vcpu_onereg.c      | 6 ++++++
>   2 files changed, 9 insertions(+)
>
> diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> index 56959d277e86..79a5ac86597c 100644
> --- a/arch/riscv/include/uapi/asm/kvm.h
> +++ b/arch/riscv/include/uapi/asm/kvm.h
> @@ -186,6 +186,9 @@ enum KVM_RISCV_ISA_EXT_ID {
>   	KVM_RISCV_ISA_EXT_ZAAMO,
>   	KVM_RISCV_ISA_EXT_ZALRSC,
>   	KVM_RISCV_ISA_EXT_ZICBOP,
> +	KVM_RISCV_ISA_EXT_ZFBFMIN,
> +	KVM_RISCV_ISA_EXT_ZVFBFMIN,
> +	KVM_RISCV_ISA_EXT_ZVFBFWMA,
>   	KVM_RISCV_ISA_EXT_MAX,
>   };
>   
> diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c
> index d444ec9e9e8e..2ba3f2c942ee 100644
> --- a/arch/riscv/kvm/vcpu_onereg.c
> +++ b/arch/riscv/kvm/vcpu_onereg.c
> @@ -65,6 +65,7 @@ static const unsigned long kvm_isa_ext_arr[] = {
>   	KVM_ISA_EXT_ARR(ZCF),
>   	KVM_ISA_EXT_ARR(ZCMOP),
>   	KVM_ISA_EXT_ARR(ZFA),
> +	KVM_ISA_EXT_ARR(ZFBFMIN),
>   	KVM_ISA_EXT_ARR(ZFH),
>   	KVM_ISA_EXT_ARR(ZFHMIN),
>   	KVM_ISA_EXT_ARR(ZICBOM),
> @@ -89,6 +90,8 @@ static const unsigned long kvm_isa_ext_arr[] = {
>   	KVM_ISA_EXT_ARR(ZTSO),
>   	KVM_ISA_EXT_ARR(ZVBB),
>   	KVM_ISA_EXT_ARR(ZVBC),
> +	KVM_ISA_EXT_ARR(ZVFBFMIN),
> +	KVM_ISA_EXT_ARR(ZVFBFWMA),
>   	KVM_ISA_EXT_ARR(ZVFH),
>   	KVM_ISA_EXT_ARR(ZVFHMIN),
>   	KVM_ISA_EXT_ARR(ZVKB),
> @@ -170,6 +173,7 @@ static bool kvm_riscv_vcpu_isa_disable_allowed(unsigned long ext)
>   	case KVM_RISCV_ISA_EXT_ZCF:
>   	case KVM_RISCV_ISA_EXT_ZCMOP:
>   	case KVM_RISCV_ISA_EXT_ZFA:
> +	case KVM_RISCV_ISA_EXT_ZFBFMIN:
>   	case KVM_RISCV_ISA_EXT_ZFH:
>   	case KVM_RISCV_ISA_EXT_ZFHMIN:
>   	case KVM_RISCV_ISA_EXT_ZICBOP:
> @@ -192,6 +196,8 @@ static bool kvm_riscv_vcpu_isa_disable_allowed(unsigned long ext)
>   	case KVM_RISCV_ISA_EXT_ZTSO:
>   	case KVM_RISCV_ISA_EXT_ZVBB:
>   	case KVM_RISCV_ISA_EXT_ZVBC:
> +	case KVM_RISCV_ISA_EXT_ZVFBFMIN:
> +	case KVM_RISCV_ISA_EXT_ZVFBFWMA:
>   	case KVM_RISCV_ISA_EXT_ZVFH:
>   	case KVM_RISCV_ISA_EXT_ZVFHMIN:
>   	case KVM_RISCV_ISA_EXT_ZVKB:

Reviewed-by: Nutty Liu<liujingqi@xxxxxxxxxxxxxxxxxxx>

Thanks,
Nutty