linux-kernel - Re: [PATCH v3 04/12] KVM: X86: Add a ratio parameter to kvm_scale

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Message-ID: <cba90aa4-0665-a2d5-29e0-133e0aa45ad2@redhat.com>
Date:   Mon, 24 May 2021 16:23:05 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Ilias Stamatis <ilstam@...zon.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     mlevitsk@...hat.com, seanjc@...gle.com, vkuznets@...hat.com,
        wanpengli@...cent.com, jmattson@...gle.com, joro@...tes.org,
        zamsden@...il.com, mtosatti@...hat.com, dwmw@...zon.co.uk
Subject: Re: [PATCH v3 04/12] KVM: X86: Add a ratio parameter to
 kvm_scale_tsc()

On 21/05/21 12:24, Ilias Stamatis wrote:
> @@ -3537,10 +3539,14 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>   		 * return L1's TSC value to ensure backwards-compatible
>   		 * behavior for migration.
>   		 */
> -		u64 tsc_offset = msr_info->host_initiated ? vcpu->arch.l1_tsc_offset :
> -							    vcpu->arch.tsc_offset;
> -
> -		msr_info->data = kvm_scale_tsc(vcpu, rdtsc()) + tsc_offset;
> +		if (msr_info->host_initiated)
> +			msr_info->data = kvm_scale_tsc(
> +				vcpu, rdtsc(), vcpu->arch.l1_tsc_scaling_ratio
> +				) + vcpu->arch.l1_tsc_offset;

Better indentation:

	msr_info->data = vcpu->arch.l1_tsc_offset +
		kvm_scale_tsc(vcpu, rdtsc(),
			      vcpu->arch.tsc_scaling_ratio);

Same below.

Paolo

> +		else
> +			msr_info->data = kvm_scale_tsc(
> +				vcpu, rdtsc(), vcpu->arch.tsc_scaling_ratio
> +				) + vcpu->arch.tsc_offset;
>   		break;
>   	}
>   	case MSR_MTRRcap:
>