KVM: SMP: Add vcpu_id field in struct vcpu

This patch adds a `vcpu_id' field in `struct vcpu', so we can
differentiate BSP and APs without pointer comparison or arithmetic.

Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 336be86..b629a83 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -328,6 +328,7 @@
 
 struct kvm_vcpu {
 	struct kvm *kvm;
+	int vcpu_id;
 	union {
 		struct vmcs *vmcs;
 		struct vcpu_svm *svm;