chart41 wrote:
In VM's settings/acceleration I tried "Default" and "KVM" options,
If you are referring to the
Paravirtualization Interface setting then that has nothing to do with hardware virtualization. It refers to what style of API VirtualBox should offer to a modern hypervisor-aware guest OS. Linux guests can use the KVM API, Windows guests (Win8 and later) understand the Hyper-v API. This setting has nothing to do with the presence or not of hardware virtualization, nothing to do with whether the host OS is itself talking to a Hyper-v or KVM or no API, and nothing to do with
any CPU feature.
I think what you are after is the
Enable Nested VT-x/AMD-v setting on the
System|Processor tab, which causes this CPU feature to be reflected into the VM. But be aware: use of anything other that VirtualBox as a nested Hypervisor is not supported. That doesn't mean it won't work, it's just that making it work may not be a high priority.