kvm: x86: fix kvm_apic_has_events to check for NULL pointer

commit ce40cd3f upstream.

Malicious (or egregiously buggy) userspace can trigger it, but it
should never happen in normal operation.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reference: CVE-2015-4692
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

arch/x86/kvm/lapic.h

@@ -165,7 +165,7 @@ static inline u16 apic_logical_id(struct kvm_apic_map *map, u32 ldr)
 
 static inline bool kvm_apic_has_events(struct kvm_vcpu *vcpu)
 {
-	return vcpu->arch.apic->pending_events;
+	return kvm_vcpu_has_lapic(vcpu) && vcpu->arch.apic->pending_events;
 }
 
 bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector);