Re: [PATCH 08/12] KVM: x86: Use the correct vcpu's TSC rate to compute time scale

[Radim KrÄmÃÅ]

2015-09-28 13:38+0800, Haozhong Zhang:
> This patch makes KVM use virtual_tsc_khz rather than the host TSC rate
> as vcpu's TSC rate to compute the time scale if TSC scaling is enabled.
> 
> Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
> ---
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> @@ -1782,7 +1782,9 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
>  		return 0;
>  
>  	if (unlikely(vcpu->hw_tsc_khz != this_tsc_khz)) {
> -		kvm_get_time_scale(NSEC_PER_SEC / 1000, this_tsc_khz,
> +		tgt_tsc_khz = kvm_has_tsc_control ?
> +			vcpu->virtual_tsc_khz : this_tsc_khz;
> +		kvm_get_time_scale(NSEC_PER_SEC / 1000, tgt_tsc_khz,
>  				   &vcpu->hv_clock.tsc_shift,
>  				   &vcpu->hv_clock.tsc_to_system_mul);

Good catch, it seems that SVM didn't scale kvmclock correctly ...
I think we'll want this patch in stable.
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