diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 2185ddc1b7..71fddfdb8f 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4075,6 +4075,7 @@ static int hvmop_set_evtchn_upcall_vector(
     printk(XENLOG_G_INFO "%pv: upcall vector %02x\n", v, op.vector);
 
     v->arch.hvm_vcpu.evtchn_upcall_vector = op.vector;
+    hvm_assert_evtchn_irq(v);
     return 0;
 }
 
diff --git a/xen/arch/x86/hvm/irq.c b/xen/arch/x86/hvm/irq.c
index 0077f68a83..f528e2d081 100644
--- a/xen/arch/x86/hvm/irq.c
+++ b/xen/arch/x86/hvm/irq.c
@@ -385,6 +385,7 @@ void hvm_set_callback_via(struct domain *d, uint64_t via)
     struct hvm_irq *hvm_irq = hvm_domain_irq(d);
     unsigned int gsi=0, pdev=0, pintx=0;
     uint8_t via_type;
+    struct vcpu *v;
 
     via_type = (uint8_t)MASK_EXTR(via, HVM_PARAM_CALLBACK_IRQ_TYPE_MASK) + 1;
     if ( ((via_type == HVMIRQ_callback_gsi) && (via == 0)) ||
@@ -447,6 +448,10 @@ void hvm_set_callback_via(struct domain *d, uint64_t via)
 
     spin_unlock(&d->arch.hvm_domain.irq_lock);
 
+    for_each_vcpu ( d, v )
+        if ( is_vcpu_online(v) )
+            hvm_assert_evtchn_irq(v);
+
 #ifndef NDEBUG
     printk(XENLOG_G_INFO "Dom%u callback via changed to ", d->domain_id);
     switch ( via_type )