From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com>
Date: Fri, 6 Oct 2017 19:25:53 +0200
Subject: KVM: x86: handle 0 write to TSC_DEADLINE MSR
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Patch-mainline: v4.15-rc1
Git-commit: 86bbc1e6d7ce016f1b2e8c29864cd7b75b00ff96
References: bsc#1077761

0 should disable the timer, but start_hv_timer will recognize it as an
expired timer instead.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@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
@@ -1549,6 +1549,9 @@
 	if (!apic_lvtt_period(apic) && atomic_read(&ktimer->pending))
 		return false;
 
+	if (!ktimer->tscdeadline)
+		return false;
+
 	r = kvm_x86_ops->set_hv_timer(apic->vcpu, ktimer->tscdeadline);
 	if (r < 0)
 		return false;