KVM: read apic->irr with ioapic lock held

Read ioapic->irr inside ioapic->lock protected section.

KVM-Stable-Tag
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

virt/kvm/ioapic.c

@@ -192,12 +192,13 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
 
 int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
 {
-	u32 old_irr = ioapic->irr;
+	u32 old_irr;
 	u32 mask = 1 << irq;
 	union kvm_ioapic_redirect_entry entry;
 	int ret = 1;
 
 	spin_lock(&ioapic->lock);
+	old_irr = ioapic->irr;
 	if (irq >= 0 && irq < IOAPIC_NUM_PINS) {
 		entry = ioapic->redirtbl[irq];
 		level ^= entry.fields.polarity;