KVM: check injected pic irq within valid pic irqs

Check that an injected pic irq is between 0 and 15.
Signed-off-by: NBen-Ami Yassour <benami@il.ibm.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

arch/x86/kvm/i8259.c

@@ -130,8 +130,10 @@ void kvm_pic_set_irq(void *opaque, int irq, int level)
 {
 	struct kvm_pic *s = opaque;
 
-	pic_set_irq1(&s->pics[irq >> 3], irq & 7, level);
-	pic_update_irq(s);
+	if (irq >= 0 && irq < PIC_NUM_PINS) {
+		pic_set_irq1(&s->pics[irq >> 3], irq & 7, level);
+		pic_update_irq(s);
+	}
 }
 
 /*

arch/x86/kvm/irq.h

@@ -30,6 +30,8 @@
 #include "ioapic.h"
 #include "lapic.h"
 
+#define PIC_NUM_PINS 16
+
 struct kvm;
 struct kvm_vcpu;