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>
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 7c79c1d..3500dee 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -192,12 +192,13 @@
 
 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;