linux-kernel - [PATCH v2 1/2] KVM: LAPIC: Disarm LAPIC timer includes pending timer around TSC deadline switch

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Date:   Tue, 10 May 2022 19:38:29 -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 1/2] KVM: LAPIC: Disarm LAPIC timer includes pending timer around TSC deadline switch

From: Wanpeng Li <wanpengli@...cent.com>

The timer is disarmed when switching between TSC deadline and other modes, 
however, the pending timer is still in-flight, so let's accurately set 
everything to a disarmed state, this patch does it by clearing pending
when canceling the timer.

Fixes: 4427593258 (KVM: x86: thoroughly disarm LAPIC timer around TSC deadline switch)
Signed-off-by: Wanpeng Li <wanpengli@...cent.com>
---
v1 -> v2:
 * clear pending in cancel_apic_timer

 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 66b0eb0bda94..6268880c8eed 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1548,6 +1548,7 @@ static void cancel_apic_timer(struct kvm_lapic *apic)
 	if (apic->lapic_timer.hv_timer_in_use)
 		cancel_hv_timer(apic);
 	preempt_enable();
+	atomic_set(&apic->lapic_timer.pending, 0);
 }
 
 static void apic_update_lvtt(struct kvm_lapic *apic)
-- 
2.25.1