Dear developer: I am facing confusing problems, there is no way for me to figure it out, so I have to ask for help: 1. I am using the <asm/kvm_host.h> <linux/kvm_host.h> for using kvm in my module, but there are always some function undefined like kvm_arch_mmu_notifier_invalidate_range. Are those functions not visiable from outside? 2. With the ept technology, If I use "alloc_page" inside the guest virtual machine, and use "page_to_pfn" to get the pfn of the certain page, Is the pfn I get the gfn or the pfn of the host machine? 3. I want to modify the EPT table, so that I can make the gva point to certain hpa just to share information between vm, Given the condition that I can not modify the kvm code, Is that possible? 4. Do you have some technology about sharing memory between virtual machine with some example code? sorry for trouble, but I really find it hart to solve it only by myself.