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>
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 997bb3e..b0a13d1 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -283,6 +283,7 @@
  * Extension capability list.
  */
 #define KVM_CAP_IRQCHIP	  0
+#define KVM_CAP_HLT	  1
 
 /*
  * ioctls for VM fds