netdev - Re: [PATCH v14 07/10] arm64/kvm: Add hypercall service for kvm ptp.

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Message-ID: <87363wmqmt.wl-maz@kernel.org>
Date:   Sat, 05 Sep 2020 12:04:10 +0100
From:   Marc Zyngier <maz@...nel.org>
To:     Jianyong Wu <jianyong.wu@....com>
Cc:     netdev@...r.kernel.org, yangbo.lu@....com, john.stultz@...aro.org,
        tglx@...utronix.de, pbonzini@...hat.com,
        sean.j.christopherson@...el.com, richardcochran@...il.com,
        Mark.Rutland@....com, will@...nel.org, suzuki.poulose@....com,
        steven.price@....com, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        kvm@...r.kernel.org, Steve.Capper@....com, justin.he@....com,
        nd@....com
Subject: Re: [PATCH v14 07/10] arm64/kvm: Add hypercall service for kvm ptp.

On Fri, 04 Sep 2020 10:27:41 +0100,
Jianyong Wu <jianyong.wu@....com> wrote:
> 
> ptp_kvm will get this service through smccc call.
> The service offers wall time and counter cycle of host for guest.
> caller must explicitly determines which cycle of virtual counter or
> physical counter to return if it needs counter cycle.
> 
> Signed-off-by: Jianyong Wu <jianyong.wu@....com>
> ---
>  arch/arm64/kvm/Kconfig       |  6 +++++
>  arch/arm64/kvm/arch_timer.c  |  2 +-
>  arch/arm64/kvm/hypercalls.c  | 49 ++++++++++++++++++++++++++++++++++++
>  include/kvm/arm_arch_timer.h |  1 +
>  include/linux/arm-smccc.h    | 16 ++++++++++++
>  5 files changed, 73 insertions(+), 1 deletion(-)
>

[...]

On top of what I said yesterday:

> index 32ba6fbc3814..eb85f6701845 100644
> --- a/arch/arm64/kvm/arch_timer.c
> +++ b/arch/arm64/kvm/arch_timer.c
> @@ -81,7 +81,7 @@ u64 timer_get_cval(struct arch_timer_context *ctxt)
>  	}
>  }
>  
> -static u64 timer_get_offset(struct arch_timer_context *ctxt)
> +u64 timer_get_offset(struct arch_timer_context *ctxt)
>  {
>  	struct kvm_vcpu *vcpu = ctxt->vcpu;
>

Why has this become global? I can't see a reason why we would want to
expose this purely KVM internal helper.

	M.

-- 
Without deviation from the norm, progress is not possible.