DMA Attack Surface & IOMMU Protection

A laptop's Thunderbolt / USB-C port exposes raw PCIe, and PCIe peripherals can issue Direct Memory Access requests straight to physical RAM, bypassing the CPU entirely. This simulator renders a 3D model of that path: a peripheral fires DMA requests at a grid of 128 physical memory pages, and an IOMMU translation gate either lets each request through or blocks it in hardware, exactly as Intel VT-d / AMD-Vi and OS-level Kernel DMA Protection do on real machines. Toggle the IOMMU, switch the device between a trusted peripheral and a malicious/compromised one, resize its mapped DMA buffer, and watch the live allowed/blocked/kernel-touched counters to see why disabling DMA protection — or over-provisioning a device's buffer — directly widens the attack surface.