KVM: In kernel PIT model

The patch moves the PIT model from userspace to kernel, and increases
the timer accuracy greatly.

[marcelo: make last_injected_time per-guest]

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Tested-and-Acked-by: Alex Davis <alex14641@yahoo.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index e92e703..cefa9a2 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -236,6 +236,7 @@
 #define KVM_CAP_CLOCKSOURCE 8
 #define KVM_CAP_NR_VCPUS 9       /* returns max vcpus per vm */
 #define KVM_CAP_NR_MEMSLOTS 10   /* returns max memory slots per vm */
+#define KVM_CAP_PIT 11
 
 /*
  * ioctls for VM fds
@@ -258,6 +259,7 @@
 #define KVM_IRQ_LINE		  _IOW(KVMIO, 0x61, struct kvm_irq_level)
 #define KVM_GET_IRQCHIP		  _IOWR(KVMIO, 0x62, struct kvm_irqchip)
 #define KVM_SET_IRQCHIP		  _IOR(KVMIO,  0x63, struct kvm_irqchip)
+#define KVM_CREATE_PIT		  _IO(KVMIO,  0x64)
 
 /*
  * ioctls for vcpu fds