Before hardware support for virtualization with the introduction of Intel VT-x (and AMD-v), was it possible for a VM guest OS to detect the following with the results of a single instruction (ignoring timing): If it was running as a guest (i.e. virtualized). If it was running in a type-1 as opposed to a type-2 hypervisor. A) Guest can tell it is virtualized: Yes. Guest can distinguish type-1 from type-2: No. B) Guest can tell it is virtualized: Yes, but only if sensitive instructions trap to the hypervisor. Guest can distinguish type-1 from type-2: No. C) Guest can tell it is virtualized: No. Guest can distinguish type-1 from type-2: No. D) Guest can tell it is virtualized: Yes. Guest can distinguish type-1 from type-2: Yes.