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Date: Mon, 7 Jun 2021 00:19:43 -0700 From: Wanpeng Li <kernellwp@...il.com> To: linux-kernel@...r.kernel.org, kvm@...r.kernel.org Cc: Paolo Bonzini <pbonzini@...hat.com>, Sean Christopherson <seanjc@...gle.com>, Vitaly Kuznetsov <vkuznets@...hat.com>, Wanpeng Li <wanpengli@...cent.com>, Jim Mattson <jmattson@...gle.com>, Joerg Roedel <joro@...tes.org> Subject: [PATCH v2 1/3] KVM: LAPIC: Write 0 to TMICT should also cancel vmx-preemption timer From: Wanpeng Li <wanpengli@...cent.com> According to the SDM 10.5.4.1: A write of 0 to the initial-count register effectively stops the local APIC timer, in both one-shot and periodic mode. However, the lapic timer oneshot/periodic mode which is emulated by vmx-preemption timer doesn't stop by writing 0 to TMICT since vmx->hv_deadline_tsc is still programmed and the guest will receive the spurious timer interrupt later. This patch fixes it by also cancelling the vmx-preemption timer when writing 0 to the initial-count register. Reviewed-by: Sean Christopherson <seanjc@...gle.com> Signed-off-by: Wanpeng Li <wanpengli@...cent.com> --- v1 -> v2: * rename to cancel_apic_timer * update patch description arch/x86/kvm/lapic.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 8120e86..6d72d8f 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1494,6 +1494,15 @@ static void limit_periodic_timer_frequency(struct kvm_lapic *apic) static void cancel_hv_timer(struct kvm_lapic *apic); +static void cancel_apic_timer(struct kvm_lapic *apic) +{ + hrtimer_cancel(&apic->lapic_timer.timer); + preempt_disable(); + if (apic->lapic_timer.hv_timer_in_use) + cancel_hv_timer(apic); + preempt_enable(); +} + static void apic_update_lvtt(struct kvm_lapic *apic) { u32 timer_mode = kvm_lapic_get_reg(apic, APIC_LVTT) & @@ -1502,11 +1511,7 @@ static void apic_update_lvtt(struct kvm_lapic *apic) if (apic->lapic_timer.timer_mode != timer_mode) { if (apic_lvtt_tscdeadline(apic) != (timer_mode == APIC_LVT_TIMER_TSCDEADLINE)) { - hrtimer_cancel(&apic->lapic_timer.timer); - preempt_disable(); - if (apic->lapic_timer.hv_timer_in_use) - cancel_hv_timer(apic); - preempt_enable(); + cancel_apic_timer(apic); kvm_lapic_set_reg(apic, APIC_TMICT, 0); apic->lapic_timer.period = 0; apic->lapic_timer.tscdeadline = 0; @@ -2092,7 +2097,7 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val) if (apic_lvtt_tscdeadline(apic)) break; - hrtimer_cancel(&apic->lapic_timer.timer); + cancel_apic_timer(apic); kvm_lapic_set_reg(apic, APIC_TMICT, val); start_apic_timer(apic); break; -- 2.7.4
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