According to one general aspect, a memory management unit (MMU) may be configured to interface with a heterogeneous memory system that comprises a plurality of types of storage mediums. Each type of storage medium may be based upon a respective memory technology and may be associated with performance characteristic(s). The MMU may receive a data access for the heterogeneous memory system. The MMU may also determine at least one of the storage mediums of the heterogeneous memory system to service the data access. The target storage medium may be selected based upon at least one performance characteristic associated with the target storage medium and a quality of service tag that is associated with the virtual machine and that indicates one or more performance characteristics. The MMU may route the data access by the virtual machine to the at least one of the storage mediums.