1. A system comprising: a switch that receives packets from and delivers packets to one or more devices connected to a bus without any components on the bus between the switch and each of the devices; a memory integrated into the switch to store a mapping of virtual addresses to physical addresses; and a non-transitory computer readable storage medium integrated into the switch storing instructions executable by the switch and upon such execution cause the switch to perform operations comprising: receiving, by the switch from a device connected to the switch by the bus, a memory access request that includes a particular physical address; retrieving, by the switch from the memory, a mapping of a virtual address to a physical address in response to receiving the memory access request that includes the particular physical address; determining, using the mapping of the virtual address to a physical address, that the particular physical address is stored in the memory; and forwarding the memory access request to another device for servicing in response to determining that the particular physical address is stored in the memory.