To transparently single-step guest OSes on Intel CPUs, the Monitor Trap Flag (MTF) can be used.
https://revers.engineering/syscall-hooking-via-extended-feature-enable-register-efer/
https://rayanfam.com/topics/hypervisor-from-scratch-part-8/
https://standa-note.blogspot.com/2015/08/
https://standa-note.blogspot.com/2020/11/