An input-output (IO) memory management unit (IOMMU) uses a reverse map table (RMT) to ensure that address translations acquired from a nested page table are correct and that IO devices are permitted to access pages in a memory when performing memory accesses in a computing device. A translation lookaside buffer (TLB) flushing mechanism is used to invalidate address translation information in TLBs that are affected by changes in the RMT. A modified Address Translation Caching (ATC) mechanism may be used, in which only partial address translation information is provided to IO devices so that the RMT is checked when performing memory accesses for the IO devices using the cached address translation information.