Has anybody actually done this? VirtualBox does not virtualize the VT-x/SVM support of the hardware to the guest OS (nor does any other hypervisor, afaik). The Linux OS running under VirtualBox of the host Windows machine will never detect VT-x/SVM, and so the hardware required by QEMU, kvm, etc. won't be there, right? If so this page will lead some down a cruel dead-end path. Otherwise the details for circumventing the issue need to be given here.