WinVisor – A hypervisor-based emulator for Windows x64 user-mode executables

This article presents WinVisor, a user‑mode Windows x64 virtualization framework built on the Windows Hypervisor Platform that clones a target process’s address space, initializes a virtual CPU via a CPL0 bootloader, and intercepts/logs syscalls (including legacy INT 2E) while handling paging, TLB flushes, and interrupts through placeholder traps. It covers VMX/WHP abstractions, GDT/IDT/TSS setup, MSR configuration, on-demand host/guest memory mirroring, a heuristic for syscall parameter counting via WoW64 stubs, and a workaround for a WHP hypervisor shared page bug, and it highlights major limitations (unsafe sandboxing, RWX mirroring, single-thread support, partial GUI virtualization, and lack of virtualized software exception handling), with source code available on GitHub.