1. A method, comprising: storing, by one or more processors, confidential data in a confidential section of virtual memory, wherein storing the confidential data in the confidential section of virtual memory comprises: mapping the confidential section of virtual memory to an address space in a first physical memory device; storing the confidential data in the first physical memory device; and marking the address space in the first physical memory device as having confidential data; receiving a request to copy data stored in the address space in the first physical memory device to a second physical memory device, wherein the second physical memory device has more capacity and slower memory access speed than the first physical memory device; determining that the address space in the first physical memory device has been marked as having confidential data; and denying the request to copy in response to determining that the address space in the first physical memory device has been marked as having confidential data.