KVM: Introduce kvm_set_irq to inject interrupts in guests

This function injects an interrupt into the guest given the kvm struct,
the (guest) irq number and the interrupt level.
Signed-off-by: NAmit Shah <amit.shah@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

arch/x86/kvm/irq.c

@@ -100,3 +100,14 @@ void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
 	__kvm_migrate_apic_timer(vcpu);
 	__kvm_migrate_pit_timer(vcpu);
 }
+
+/* This should be called with the kvm->lock mutex held */
+void kvm_set_irq(struct kvm *kvm, int irq, int level)
+{
+	/* Not possible to detect if the guest uses the PIC or the
+	 * IOAPIC.  So set the bit in both. The guest will ignore
+	 * writes to the unused one.
+	 */
+	kvm_ioapic_set_irq(kvm->arch.vioapic, irq, level);
+	kvm_pic_set_irq(pic_irqchip(kvm), irq, level);
+}

arch/x86/kvm/irq.h

@@ -82,6 +82,8 @@ static inline int irqchip_in_kernel(struct kvm *kvm)
 
 void kvm_pic_reset(struct kvm_kpic_state *s);
 
+void kvm_set_irq(struct kvm *kvm, int irq, int level);
+
 void kvm_timer_intr_post(struct kvm_vcpu *vcpu, int vec);
 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu);
 void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu);