Aspects relate to Input/Output (IO) Memory Management Units (MMUs) that include hardware structures for implementing virtualization. Some implementations allow guests to setup and maintain device IO tables within memory regions to which those guests have been given permissions by a hypervisor. Some implementations provide hardware page table walking capability within the IOMMU, while other implementations provide static tables. Such static tables may be maintained by a hypervisor on behalf of guests. Some implementations reduce a frequency of interrupts or invocation of hypervisor by allowing transactions to be setup by guests without hypervisor involvement within their assigned device IO regions. Devices may communicate with IOMMU to setup the requested memory transaction, and completion thereof may be signaled to the guest without hypervisor involvement. Various other aspects will be evident from the disclosure.