An IOMMU serves a slightly different purpose than a normal MMU. The graphic on Wikipedia [0] sums it up pretty well. The lack of an IOMMU would mean that if the

An IOMMU serves a slightly different purpose than a normal MMU. The graphic on Wikipedia [0] sums it up pretty well. The lack of an IOMMU would mean that if the firmware on the USB controller was malicious in some way, it could access memory it would otherwise not have access to. 0: https://en.wikipedia.org/wiki/Input%E2%80%93output_memory_management_unit https://en.wikipedia.org/wiki/Input%E2%80%93output_memory_ma...