From: Wanpeng Li <wanpeng.li@hotmail.com>
Date: Thu, 5 Oct 2017 03:53:51 -0700
Subject: KVM: LAPIC: Fix lapic timer mode transition
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Patch-mainline: v4.15-rc1
Git-commit: c69518c86be5000bf4d8eb0e0d279d40779d2a18
References: bsc#1077761

SDM 10.5.4.1 TSC-Deadline Mode mentioned that "Transitioning between TSC-Deadline
mode and other timer modes also disarms the timer". So the APIC Timer Initial Count
Register for one-shot/periodic mode should be reset. This patch do it.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
[Removed unnecessary definition of APIC_LVT_TIMER_MASK.]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Acked-by: Alexander Graf <agraf@suse.de>
---
 arch/x86/kvm/lapic.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1307,6 +1307,9 @@
 			apic->lapic_timer.timer_mode_mask;
 
 	if (apic->lapic_timer.timer_mode != timer_mode) {
+		if (apic_lvtt_tscdeadline(apic) != (timer_mode ==
+				APIC_LVT_TIMER_TSCDEADLINE))
+			kvm_lapic_set_reg(apic, APIC_TMICT, 0);
 		apic->lapic_timer.timer_mode = timer_mode;
 		hrtimer_cancel(&apic->lapic_timer.timer);
 	}