KVM: LAPIC: Also cancel preemption timer when disarm LAPIC timer

The timer is disarmed when switching between TSC deadline and other modes,
we should set everything to disarmed state, however, LAPIC timer can be
emulated by preemption timer, it still works if vmx->hv_deadline_timer is
not -1. This patch also cancels preemption timer when disarm LAPIC timer.
Signed-off-by: NWanpeng Li <wanpengli@tencent.com>
Message-Id: <1585031530-19823-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/lapic.c

@@ -1445,6 +1445,8 @@ static void limit_periodic_timer_frequency(struct kvm_lapic *apic)
 	}
 }
 
+static void cancel_hv_timer(struct kvm_lapic *apic);
+
 static void apic_update_lvtt(struct kvm_lapic *apic)
 {
 	u32 timer_mode = kvm_lapic_get_reg(apic, APIC_LVTT) &
@@ -1454,6 +1456,10 @@ static void apic_update_lvtt(struct kvm_lapic *apic)
 		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();
 			kvm_lapic_set_reg(apic, APIC_TMICT, 0);
 			apic->lapic_timer.period = 0;
 			apic->lapic_timer.tscdeadline = 0;