Re: [PATCH RFC v2 3/3] riscv: KVM: Add Svukte extension support for Guest/VM

[Anup Patel <anup@brainfault.org>]

On Fri, Sep 27, 2024 at 7:12 PM Max Hsu <max.hsu@sifive.com> wrote:
>
> Add KVM ISA extension ONE_REG interface to allow VMM tools to
> detect and enable Svukte extension for Guest/VM.
>
> Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
> Signed-off-by: Max Hsu <max.hsu@sifive.com>
> ---
>  arch/riscv/include/uapi/asm/kvm.h | 1 +
>  arch/riscv/kvm/vcpu_onereg.c      | 1 +
>  2 files changed, 2 insertions(+)
>
> diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> index e97db3296456e19f79ca02e4c4f70ae1b4abb48b..41b466b7ffaec421e8389d3f5b178580091a2c98 100644
> --- a/arch/riscv/include/uapi/asm/kvm.h
> +++ b/arch/riscv/include/uapi/asm/kvm.h
> @@ -175,6 +175,7 @@ enum KVM_RISCV_ISA_EXT_ID {
>         KVM_RISCV_ISA_EXT_ZCF,
>         KVM_RISCV_ISA_EXT_ZCMOP,
>         KVM_RISCV_ISA_EXT_ZAWRS,
> +       KVM_RISCV_ISA_EXT_SVUKTE,
>         KVM_RISCV_ISA_EXT_MAX,
>  };
>
> diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c
> index b319c4c13c54ce22d2a7552f4c9f256a0c50780e..67237d6e53882a9fcd2cf265aa1704f25cc4a701 100644
> --- a/arch/riscv/kvm/vcpu_onereg.c
> +++ b/arch/riscv/kvm/vcpu_onereg.c
> @@ -41,6 +41,7 @@ static const unsigned long kvm_isa_ext_arr[] = {
>         KVM_ISA_EXT_ARR(SVINVAL),
>         KVM_ISA_EXT_ARR(SVNAPOT),
>         KVM_ISA_EXT_ARR(SVPBMT),
> +       KVM_ISA_EXT_ARR(SVUKTE),
>         KVM_ISA_EXT_ARR(ZACAS),
>         KVM_ISA_EXT_ARR(ZAWRS),
>         KVM_ISA_EXT_ARR(ZBA),

The KVM_RISCV_ISA_EXT_SVUKTE should be added to the
switch-case in kvm_riscv_vcpu_isa_disable_allowed() because
hypervisor seems to have no way to disable Svukte for the Guest
when it's available on the Host.

Regards,
Anup