KVM: x86: handle 0 write to TSC_DEADLINE MSR

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>

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 2c9e88a..39c1ae1 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1549,6 +1549,9 @@ static bool start_hv_timer(struct kvm_lapic *apic)
        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;