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, 6 insertions, 0 deletions

diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 23b81cf242af..e85a2bcd2db1 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -101,6 +101,7 @@ static void ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
 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 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
                 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 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
                         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 @@ int kvm_ioapic_init(struct kvm *kvm)
         kvm_io_bus_register_dev(&kvm->mmio_bus, &ioapic->dev);
         return 0;
 }
+