KVM: Export necessary function for EPT

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e89338e..f7ba099 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -522,6 +522,7 @@
 		return bad_hva();
 	return (slot->userspace_addr + (gfn - slot->base_gfn) * PAGE_SIZE);
 }
+EXPORT_SYMBOL_GPL(gfn_to_hva);
 
 /*
  * Requires current->mm->mmap_sem to be held