An IOMMU (Input–Output Memory Management Unit) is a hardware component that virtualizes and protects system memory from peripheral devices performing direct memory access (DMA). It maps device-visible virtual addresses to physical addresses, enabling device isolation, protection, and virtualized device passthrough.

Key IOMMU features and use cases:

• Device isolation and protection from rogue or malfunctioning peripherals.
• PCIe SR-IOV and passthrough: Safe assignment of devices to virtual machines or containers.
• Address translation for scatter-gather DMA and large memory systems.
• Security mechanisms against DMA-based attacks.

IOMMUs are fundamental for secure and high-performance virtualization, allowing direct device access without compromising system memory safety. They also improve performance by enabling efficient DMA and by offloading address translation responsibilities from software.

Strategic advantages of IOMMU:

• Secure device isolation for multi-tenant and virtualized environments.
• Enables near-native I/O performance for VMs via passthrough.
• Supports advanced device features like SR-IOV for scalability.
• Improves reliability and safety of DMA operations.

• IOMMU: Wikipedia
• Kernal.org