1. A method of cloning data in a memory for a source virtual machine (VM) and at least one cloned virtual machine, wherein 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, the method comprising: copying metadata of the page tables in a highest level or higher levels of the plurality of hierarchical levels to the virtual machine; replicating remaining metadata of the page tables in the levels other than the highest level or the higher levels of the plurality of hierarchical levels to the virtual machine in response to an access operation; and accessing data stored in the corresponding address of the memory according to the metadata and the replicated metadata.