[PATCH v1] RISC-V: KVM: Allow Guest use Zihintpause extension

[Andrew Jones]

On Fri, Sep 16, 2022 at 11:16:37AM +0530, Mayuresh Chitale wrote:
> We should advertise Zihintpause ISA extension to KVM user-space whenever
> host supports it. This will allow KVM user-space (i.e. QEMU or KVMTOOL)
> to pass on this information to Guest via ISA string.
> 
> Signed-off-by: Mayuresh Chitale <mchitale at ventanamicro.com>
> ---

Applies to riscv_kvm_queue.

>  arch/riscv/include/uapi/asm/kvm.h | 1 +
>  arch/riscv/kvm/vcpu.c             | 2 ++
>  2 files changed, 3 insertions(+)
> 
> diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> index b6770ee08872..9085b90cf324 100644
> --- a/arch/riscv/include/uapi/asm/kvm.h
> +++ b/arch/riscv/include/uapi/asm/kvm.h
> @@ -99,6 +99,7 @@ enum KVM_RISCV_ISA_EXT_ID {
>  	KVM_RISCV_ISA_EXT_SVPBMT,
>  	KVM_RISCV_ISA_EXT_SSTC,
>  	KVM_RISCV_ISA_EXT_SVINVAL,
> +	KVM_RISCV_ISA_EXT_ZIHINTPAUSE,
>  	KVM_RISCV_ISA_EXT_MAX,
>  };
>  
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index 901bb5c0cb50..0de0dd22e734 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -54,6 +54,7 @@ static const unsigned long kvm_isa_ext_arr[] = {
>  	RISCV_ISA_EXT_SVPBMT,
>  	RISCV_ISA_EXT_SSTC,
>  	RISCV_ISA_EXT_SVINVAL,
> +	RISCV_ISA_EXT_ZIHINTPAUSE,
>  };
>  
>  static unsigned long kvm_riscv_vcpu_base2isa_ext(unsigned long base_ext)
> @@ -89,6 +90,7 @@ static bool kvm_riscv_vcpu_isa_disable_allowed(unsigned long ext)
>  	case KVM_RISCV_ISA_EXT_M:
>  	case KVM_RISCV_ISA_EXT_SSTC:
>  	case KVM_RISCV_ISA_EXT_SVINVAL:
> +	case KVM_RISCV_ISA_EXT_ZIHINTPAUSE:
>  		return false;
>  	default:
>  		break;
> -- 
> 2.34.1
> 
>

Reviewed-by: Andrew Jones <ajones at ventanamicro.com>