KVM: Emulate hlt in the kernel

By sleeping in the kernel when hlt is executed, we simplify the in-kernel
guest interrupt path considerably.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/i8259.c

@@ -413,8 +413,11 @@ static void picdev_read(struct kvm_io_device *this,
 static void pic_irq_request(void *opaque, int level)
 {
 	struct kvm *kvm = opaque;
+	struct kvm_vcpu *vcpu = kvm->vcpus[0];
 
 	pic_irqchip(kvm)->output = level;
+	if (vcpu)
+		kvm_vcpu_kick(vcpu);
 }
 
 struct kvm_pic *kvm_create_pic(struct kvm *kvm)