diff --git a/xen/arch/x86/hvm/irq.c b/xen/arch/x86/hvm/irq.c
index 52aae4565f..4da12c932e 100644
--- a/xen/arch/x86/hvm/irq.c
+++ b/xen/arch/x86/hvm/irq.c
@@ -321,9 +321,10 @@ void hvm_assert_evtchn_irq(struct vcpu *v)
 
     if ( v->arch.hvm.evtchn_upcall_vector != 0 )
     {
-        uint8_t vector = v->arch.hvm.evtchn_upcall_vector;
+        struct vlapic *vlapic = vcpu_vlapic(v);
 
-        vlapic_set_irq(vcpu_vlapic(v), vector, 0);
+        if ( vlapic_enabled(vlapic) )
+           vlapic_set_irq(vlapic, v->arch.hvm.evtchn_upcall_vector, 0);
     }
     else if ( is_hvm_pv_evtchn_vcpu(v) )
         vcpu_kick(v);
diff --git a/xen/arch/x86/hvm/vlapic.c b/xen/arch/x86/hvm/vlapic.c
index b8c84458ff..a51f172128 100644
--- a/xen/arch/x86/hvm/vlapic.c
+++ b/xen/arch/x86/hvm/vlapic.c
@@ -828,6 +828,9 @@ void vlapic_reg_write(struct vcpu *v, unsigned int reg, uint32_t val)
         {
             vlapic->hw.disabled &= ~VLAPIC_SW_DISABLED;
             pt_may_unmask_irq(vlapic_domain(vlapic), &vlapic->pt);
+            if ( v->arch.hvm.evtchn_upcall_vector &&
+                 vcpu_info(v, evtchn_upcall_pending) )
+                vlapic_set_irq(vlapic, v->arch.hvm.evtchn_upcall_vector, 0);
         }
         break;