KVM: Accelerated apic support

This adds a mechanism for exposing the virtual apic tpr to the guest, and a
protocol for letting the guest update the tpr without causing a vmexit if
conditions allow (e.g. there is no interrupt pending with a higher priority
than the new tpr).

Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 850f5ef..b27a381 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -216,6 +216,11 @@
 	__u32 reserved[8];
 };
 
+/* for KVM_SET_VAPIC_ADDR */
+struct kvm_vapic_addr {
+	__u64 vapic_addr;
+};
+
 #define KVMIO 0xAE
 
 /*
@@ -291,5 +296,7 @@
 #define KVM_GET_CPUID2            _IOWR(KVMIO, 0x91, struct kvm_cpuid2)
 /* Available with KVM_CAP_VAPIC */
 #define KVM_TPR_ACCESS_REPORTING  _IOWR(KVMIO,  0x92, struct kvm_tpr_access_ctl)
+/* Available with KVM_CAP_VAPIC */
+#define KVM_SET_VAPIC_ADDR        _IOW(KVMIO,  0x93, struct kvm_vapic_addr)
 
 #endif