Apparatuses, systems, and methods for hierarchical memory systems are described. A hierarchical memory system can leverage persistent memory to store data that is generally stored in a non-persistent memory, thereby increasing an amount of storage space allocated to a computing system at a lower cost than approaches that rely solely on non-persistent memory. An example method includes initiating a read request associated with an address from an input/output device, redirecting the read request to a hierarchical memory component, generating, by the hierarchical memory component, an interrupt message to send to a hypervisor, gathering, at the hypervisor, address register access information from the hierarchical memory component, and determining a physical location of data associated with the read request.