Re: [PATCH v2 3/3] RISC-V: KVM: Add Svadu Extension Support for Guest/VM

[Andrew Jones]

On Fri, Sep 22, 2023 at 08:56:49AM +0000, Yong-Xuan Wang wrote:
> We extend the KVM ISA extension ONE_REG interface to allow VMM
> tools  to detect and enable Svadu extension for Guest/VM.
> 
> Also set the HADE bit in henvcfg CSR if Svadu extension is
> available for Guest/VM.
> 
> Signed-off-by: Yong-Xuan Wang <yongxuan.wang@xxxxxxxxxx>
> ---
>  arch/riscv/include/uapi/asm/kvm.h | 1 +
>  arch/riscv/kvm/vcpu.c             | 3 +++
>  arch/riscv/kvm/vcpu_onereg.c      | 1 +
>  3 files changed, 5 insertions(+)
> 
> diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> index 992c5e407104..3c7a6c762d0f 100644
> --- a/arch/riscv/include/uapi/asm/kvm.h
> +++ b/arch/riscv/include/uapi/asm/kvm.h
> @@ -131,6 +131,7 @@ enum KVM_RISCV_ISA_EXT_ID {
>  	KVM_RISCV_ISA_EXT_ZICSR,
>  	KVM_RISCV_ISA_EXT_ZIFENCEI,
>  	KVM_RISCV_ISA_EXT_ZIHPM,
> +	KVM_RISCV_ISA_EXT_SVADU,

This register will show up as "new" in kselftests test[1]. We should add
another patch to this series to update the test to handle/test it.

[1] tools/testing/selftests/kvm/riscv/get-reg-list.c

>  	KVM_RISCV_ISA_EXT_MAX,
>  };
>  
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index 82229db1ce73..91b92a1f4e33 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -487,6 +487,9 @@ static void kvm_riscv_vcpu_update_config(const unsigned long *isa)
>  	if (riscv_isa_extension_available(isa, ZICBOZ))
>  		henvcfg |= ENVCFG_CBZE;
>  
> +	if (riscv_isa_extension_available(isa, SVADU))
> +		henvcfg |= ENVCFG_HADE;
> +
>  	csr_write(CSR_HENVCFG, henvcfg);
>  #ifdef CONFIG_32BIT
>  	csr_write(CSR_HENVCFGH, henvcfg >> 32);
> diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c
> index 1b7e9fa265cb..211915dad677 100644
> --- a/arch/riscv/kvm/vcpu_onereg.c
> +++ b/arch/riscv/kvm/vcpu_onereg.c
> @@ -36,6 +36,7 @@ static const unsigned long kvm_isa_ext_arr[] = {
>  	/* Multi letter extensions (alphabetically sorted) */
>  	KVM_ISA_EXT_ARR(SSAIA),
>  	KVM_ISA_EXT_ARR(SSTC),
> +	KVM_ISA_EXT_ARR(SVADU),
>  	KVM_ISA_EXT_ARR(SVINVAL),
>  	KVM_ISA_EXT_ARR(SVNAPOT),
>  	KVM_ISA_EXT_ARR(SVPBMT),
> -- 
> 2.17.1
>

Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>

Thanks,
drew