linux-kernel - Re: [RFC v2 1/2] kvm: Mechanism to copy host timekeeping parameters into guest.

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Date:   Thu, 10 Oct 2019 12:50:43 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Suleiman Souhlal <suleiman@...gle.com>, rkrcmar@...hat.com,
        tglx@...utronix.de
Cc:     john.stultz@...aro.org, sboyd@...nel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        ssouhlal@...ebsd.org, tfiga@...omium.org, vkuznets@...hat.com
Subject: Re: [RFC v2 1/2] kvm: Mechanism to copy host timekeeping parameters
 into guest.

On 10/10/19 09:30, Suleiman Souhlal wrote:
>  	kvmclock_reset(vcpu);
>  
> +	if (vcpu->arch.pv_timekeeper_enabled)
> +		atomic_dec(&pv_timekeepers_nr);
> +

Please make the new MSR systemwide, there's no need to have one copy per
vCPU.  Also, it has to be cleared on reset.  I have just sent a patch
"[PATCH] kvm: clear kvmclock MSR on reset" and CCed you, you can add the
clearing to kvmclock_reset with that patch applied.

Paolo