KVM: Interrupt mask notifiers for ioapic

Allow clients to request notifications when the guest masks or unmasks a
particular irq line.  This complements irq ack notifications, as the guest
will not ack an irq line that is masked.

Currently implemented for the ioapic only.

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index aa5d1e5c497e..5162a411e4d2 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -99,3 +99,27 @@ void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
                 clear_bit(irq_source_id, &kvm->arch.irq_states[i]);
         clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
 }
+
+void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
+                                    struct kvm_irq_mask_notifier *kimn)
+{
+        kimn->irq = irq;
+        hlist_add_head(&kimn->link, &kvm->mask_notifier_list);
+}
+
+void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
+                                      struct kvm_irq_mask_notifier *kimn)
+{
+        hlist_del(&kimn->link);
+}
+
+void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask)
+{
+        struct kvm_irq_mask_notifier *kimn;
+        struct hlist_node *n;
+
+        hlist_for_each_entry(kimn, n, &kvm->mask_notifier_list, link)
+                if (kimn->irq == irq)
+                        kimn->func(kimn, mask);
+}
+