1. A memory system comprising: a memory; and an input/output memory management unit (I/O MMU) connected to the memory, and configured to receive a virtual address received from an I/O Device and configured to translate the virtual address into a physical address in the memory, wherein to translate the virtual address: the I/O MMU searches within the I/O MMU for an entry matching the virtual address, and if no entry matching the virtual address is found within the I/O MMU as a result of searching within the I/O MMU for the entries, the I/O MMU accesses the memory, searches the memory for entries matching the virtual address, and stores the found entries within the I/O MMU.