linux-kernel - Re: [PATCH v3 09/15] KVM: nSVM: Use KVM-governed feature framework to track "TSC scaling enabled"

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Message-ID: <ZNzSymgZqozT7Tno@google.com>
Date:   Wed, 16 Aug 2023 06:44:42 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Yuan Yao <yuan.yao@...ux.intel.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Zeng Guang <guang.zeng@...el.com>,
        Yuan Yao <yuan.yao@...el.com>
Subject: Re: [PATCH v3 09/15] KVM: nSVM: Use KVM-governed feature framework to
 track "TSC scaling enabled"

On Wed, Aug 16, 2023, Yuan Yao wrote:
> On Tue, Aug 15, 2023 at 01:36:47PM -0700, Sean Christopherson wrote:
> > @@ -2981,7 +2982,8 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
> >
> >  		svm->tsc_ratio_msr = data;
> >
> > -		if (svm->tsc_scaling_enabled && is_guest_mode(vcpu))
> > +		if (guest_can_use(vcpu, X86_FEATURE_TSCRATEMSR) &&
> > +		    is_guest_mode(vcpu))
> 
> I prefer (is_guest_mode(vcpu) && ....), so I can skip them more quickly LOL.
> but anyway depends on you :-)

For this series, I want to do as much of a straight replacement as possible, i.e.
not change any ordering unless it's "necessary".