KVM: Reset PIT irq injection logic when the PIT IRQ is unmasked
While the PIT is masked the guest cannot ack the irq, so the reinject logic
will never allow the interrupt to be injected.
Fix by resetting the reinjection counters on unmask.
Unbreaks Xen.
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 69d1bbff..c13bb92 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -539,6 +539,16 @@
pit->pit_state.irq_ack = 1;
}
+static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
+{
+ struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
+
+ if (!mask) {
+ atomic_set(&pit->pit_state.pit_timer.pending, 0);
+ pit->pit_state.irq_ack = 1;
+ }
+}
+
struct kvm_pit *kvm_create_pit(struct kvm *kvm)
{
struct kvm_pit *pit;
@@ -586,6 +596,9 @@
kvm_pit_reset(pit);
+ pit->mask_notifier.func = pit_mask_notifer;
+ kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
+
return pit;
}
@@ -594,6 +607,8 @@
struct hrtimer *timer;
if (kvm->arch.vpit) {
+ kvm_unregister_irq_mask_notifier(kvm, 0,
+ &kvm->arch.vpit->mask_notifier);
mutex_lock(&kvm->arch.vpit->pit_state.lock);
timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
hrtimer_cancel(timer);
diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h
index 76959c4..6acbe4b 100644
--- a/arch/x86/kvm/i8254.h
+++ b/arch/x86/kvm/i8254.h
@@ -46,6 +46,7 @@
struct kvm *kvm;
struct kvm_kpit_state pit_state;
int irq_source_id;
+ struct kvm_irq_mask_notifier mask_notifier;
};
#define KVM_PIT_BASE_ADDRESS 0x40