Not sure exactly what it does (other than obviously being some variation on process creation), but the existence of a function whose name starts with NtVdm64 suggests to me that maybe Microsoft actually did have some plan to offer a 64-bit NTVDM, but only abandoned it after they’d already implemented this function.
I recently discovered that Windows 6.2 (more commonly known as Windows 8) added an export to Kernel32.dll called NtVdm64CreateProcessInternalW.
https://www.geoffchappell.com/studies/windows/win32/kernel32...
Not sure exactly what it does (other than obviously being some variation on process creation), but the existence of a function whose name starts with NtVdm64 suggests to me that maybe Microsoft actually did have some plan to offer a 64-bit NTVDM, but only abandoned it after they’d already implemented this function.