This document discusses creating secure virtual machines through techniques like setting breakpoints using debug registers or page table modifications. It compares Intel and AMD virtualization technologies, specifically how AMD-V can intercept the IRET instruction while both support using debug registers or page tables for breakpoints. Full virtualization of x86 on x86_64 architectures is also discussed as a way to do instruction tracing for purposes like malware analysis and reverse engineering. Limitations include supporting x86 segmentation and needing very fast storage for tracing large amounts of data.