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>
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 23b81cf..e85a2bc 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -101,6 +101,7 @@
static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
{
unsigned index;
+ bool mask_before, mask_after;
switch (ioapic->ioregsel) {
case IOAPIC_REG_VERSION:
@@ -120,6 +121,7 @@
ioapic_debug("change redir index %x val %x\n", index, val);
if (index >= IOAPIC_NUM_PINS)
return;
+ mask_before = ioapic->redirtbl[index].fields.mask;
if (ioapic->ioregsel & 1) {
ioapic->redirtbl[index].bits &= 0xffffffff;
ioapic->redirtbl[index].bits |= (u64) val << 32;
@@ -128,6 +130,9 @@
ioapic->redirtbl[index].bits |= (u32) val;
ioapic->redirtbl[index].fields.remote_irr = 0;
}
+ mask_after = ioapic->redirtbl[index].fields.mask;
+ if (mask_before != mask_after)
+ kvm_fire_mask_notifiers(ioapic->kvm, index, mask_after);
if (ioapic->irr & (1 << index))
ioapic_service(ioapic, index);
break;
@@ -426,3 +431,4 @@
kvm_io_bus_register_dev(&kvm->mmio_bus, &ioapic->dev);
return 0;
}
+
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index aa5d1e5..5162a41 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -99,3 +99,27 @@
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);
+}
+
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 04401e1..786a3ae 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -842,6 +842,9 @@
if (IS_ERR(kvm))
goto out;
+#ifdef CONFIG_HAVE_KVM_IRQCHIP
+ INIT_HLIST_HEAD(&kvm->mask_notifier_list);
+#endif
#ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
page = alloc_page(GFP_KERNEL | __GFP_ZERO);