From MS help for the sys.dm_os_sys_info view, note the bit I have added bold highlight to - WTF!:

virtual_machine_type_desc - nvarchar(60) - Describes the virtual_machine_type column. Not nullable.

ValueDescription:

None - SQL Server is not running inside a virtual machine.

HYPERVISOR - SQL Server is running inside a hypervisor, which implies a hardware-assisted virtualization. If the instance is running on the host OS, the description will still return HYPERVISOR.

Other -SQL Server is running inside a virtual machine that does not employ hardware assistant such as Microsoft Virtual PC.