Probably not, or at least, no easy, well-supported way.
See http://en.wikipedia.org/wiki/X86_virtualization#Software-based_virtualization which says
The initial version of x86-64 (AMD64) did not allow for a
software-only full virtualization due to the lack of segmentation
support in long mode, which made the protection of the hypervisor's
memory impossible, in particular, the protection of the trap handler
that runs in the guest kernel address space.[12][13]:11 and 20
Revision D and later 64-bit AMD processors (as a rule of thumb, those
manufactured in 90 nm or less) added basic support for segmentation in
long mode, making it possible to run 64-bit guests in 64-bit hosts via
binary translation. Intel did not add segmentation support to its
x86-64 implementation (Intel 64), making 64-bit software-only
virtualization impossible on Intel CPUs,
VirtualBox and VMware Workstation (and VMware Player) are "level 2 hypervisors." Hyper-V and VMware ESXi are "level 1 hypervisors."
The main difference is that a level 2 hypervisor is an application running inside an existing OS, while a level 1 hypervisor is the OS itself.
This means that when you enable Hyper-V, your Windows 10 "host" becomes a virtual machine. A special one, but nonetheless a virtual machine.
So your question would more aptly be: "Why don't VirtualBox and VMware Workstation work inside a Hyper-V virtual machine?" One can answer because as a VM, the Intel VT-X instruction are no longer accessible from your virtual machine, only the host has access to it.
QEMU works because it does not do virtualization but emulation, which is completely different and explains why QEMU is painfully slow. Virtualization is the process of running a complete isolated machine inside another, but with the help of the processor. This requires the virtual machine and the host to be instruction compatible.
Emulation is the process of running any machine inside a running OS, there is no platform restriction, and is why QEMU can run an ARM machine on an amd64 platform.
Note: QEMU has 2 operating modes:
- it can work as an emulator, this is the mode explained above
- it can work as virtualization software with the help of KVM if the guest architecture is compatible with the host's and if the VT instruction is present of course.
Best Answer
Check out my SuperUser Blog post on transferring a Windows licence to another machine, the same rules apply.
Basically the following two sections of your licence are relevant:
and
Effectively you can use the copy of Windows on the host or the guest machine, but not both at the same time, otherwise both copies need to be individually licenced.
In the blog post I have linked to a Microsoft site where you can find licences for all Microsoft software so you should be able to find out your rights.