KVM: Call ack notifiers from PIC when guest OS acks an IRQ.

Currently they are called when irq vector is been delivered.  Calling ack
notifiers at this point is wrong.  Device assignment ack notifier enables
host interrupts, but guest not yet had a chance to clear interrupt
condition in a device.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

arch/x86/kvm/i8259.c

@@ -41,25 +41,16 @@ static void pic_lock(struct kvm_pic *s)
 static void pic_unlock(struct kvm_pic *s)
 	__releases(&s->lock)
 {
-	struct kvm *kvm = s->kvm;
-	unsigned acks = s->pending_acks;
-	struct kvm_vcpu *vcpu;
-
-	s->pending_acks = 0;
-
 	spin_unlock(&s->lock);
-
-	while (acks) {
-		kvm_notify_acked_irq(kvm, SELECT_PIC(__ffs(acks)),
-				     __ffs(acks));
-		acks &= acks - 1;
-	}
 }
 
 static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
 {
 	s->isr &= ~(1 << irq);
 	s->isr_ack |= (1 << irq);
+	if (s != &s->pics_state->pics[0])
+		irq += 8;
+	kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq);
 }
 
 void kvm_pic_clear_isr_ack(struct kvm *kvm)
@@ -240,7 +231,6 @@ int kvm_pic_read_irq(struct kvm *kvm)
 	}
 	pic_update_irq(s);
 	pic_unlock(s);
-	kvm_notify_acked_irq(kvm, SELECT_PIC(irq), irq);
 
 	return intno;
 }
@@ -260,7 +250,7 @@ void kvm_pic_reset(struct kvm_kpic_state *s)
 		if (vcpu0 && kvm_apic_accept_pic_intr(vcpu0))
 			if (s->irr & (1 << irq) || s->isr & (1 << irq)) {
 				n = irq + irqbase;
-				s->pics_state->pending_acks |= 1 << n;
+				kvm_notify_acked_irq(kvm, SELECT_PIC(n), n);
 			}
 	}
 	s->last_irr = 0;