From: Paolo Bonzini <pbonzini@redhat.com>
To: Wanpeng Li <kernellwp@gmail.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH v3] KVM: LAPIC: Keep stored TMCCT register value 0 after KVM_SET_LAPIC
Date: Thu, 17 Jun 2021 20:26:15 +0200 [thread overview]
Message-ID: <02391363-6713-1548-fa4b-70b70cc96f79@redhat.com> (raw)
In-Reply-To: <1623223000-18116-1-git-send-email-wanpengli@tencent.com>
On 09/06/21 09:16, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@tencent.com>
>
> KVM_GET_LAPIC stores the current value of TMCCT and KVM_SET_LAPIC's memcpy
> stores it in vcpu->arch.apic->regs, KVM_SET_LAPIC could store zero in
> vcpu->arch.apic->regs after it uses it, and then the stored value would
> always be zero. In addition, the TMCCT is always computed on-demand and
> never directly readable.
>
> Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> ---
> arch/x86/kvm/lapic.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 6d72d8f43310..9bd29b3ca790 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -2628,6 +2628,7 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
> apic_manage_nmi_watchdog(apic, kvm_lapic_get_reg(apic, APIC_LVT0));
> update_divide_count(apic);
> __start_apic_timer(apic, APIC_TMCCT);
> + kvm_lapic_set_reg(apic, APIC_TMCCT, 0);
> kvm_apic_update_apicv(vcpu);
> apic->highest_isr_cache = -1;
> if (vcpu->arch.apicv_active) {
>
Queued, thanks.
Paolo
prev parent reply other threads:[~2021-06-17 18:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 7:16 [PATCH v3] KVM: LAPIC: Keep stored TMCCT register value 0 after KVM_SET_LAPIC Wanpeng Li
2021-06-17 4:33 ` Wanpeng Li
2021-06-17 18:26 ` Paolo Bonzini [this message]
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