A method of cloning data in a memory for a source virtual machine (VM) and at least one cloned virtual machine is proposed. A mapping relationship between a guest physical address from the source VM or the cloned VM and a host physical address of the memory is defined by a plurality of page tables configured in a plurality of hierarchical levels. In the method, metadata of the page tables in the highest level or the higher levels of the plurality of hierarchical levels is copied to the virtual machine. Remaining metadata of the page tables in the levels other than the highest level or the higher levels of the plurality of hierarchical levels is replicated to the virtual machine in response to the access operation. Data stored in the corresponding address of the memory is accessed according to the metadata and the replicated metadata.