Inside the AMD Microcode ROM

Explore the inner workings of AMD microcode in this 37-minute conference talk from the 35th Chaos Communication Congress (35C3). Delve into the successful reverse engineering of AMD CPU microcode semantics and the ability to write custom microcode programs. Learn about the mapping between physical electron microscope readouts and virtual addresses used by microcode. Discover an open-source framework for creating, disassembling, and testing microcode on AMD CPUs. Gain insights into implementing defensive measures using microcode, hijacking microcoded instructions, and creating custom microcode update verification schemes. Follow along as the speakers provide a crash course in instruction decoding, CPU architecture, and microcode principles before presenting their findings and demonstrating their framework in action.