socratis wrote:(1) The "Execute Disable Bit" (or NX bit), must be disabled in order for the host to have NX-enabled [...]
(2) [...] the host to have NX-enabled, which is a requirement for some (almost all these days) VMs.
(3) See viewtopic.php?f=6&t=88942#p426401
While (2) and (3) are correct, IMHO I have to object to (1):
The page table entry bit called NX (No-eXecute) or XD (eXecute Disabled) has to be
enabled in the BIOS. The corresponding BIOS setting may have a (double) negative designation/description that can be misunderstood, though, so one has to be careful with it. If the BIOS allows the CPU/OS to use the NX/XD bit (and Windows 10 requires using it), then everything is fine.
Regarding the VirtualBox default of the PAE/NX setting: For Windows 10
64-bit the default is
off (doesn't matter), because the NX bit (bit 63 of page table entries) is available anyway, whereas for Windows 10
32-bit the default is
on (and necessary), because the page table entries would have only 32 bits when not using PAE and wouldn't have the NX bit available then.
scottgus1 wrote:00:00:01.651718 HM: HMR3Init: Attempting fall back to NEM: VT-x is not available
00:00:01.698102 NEM: WHvCapabilityCodeHypervisorPresent is TRUE, so this might work...
I don't know how the NX/XD BIOS setting interacts with the
fallback to NEM case of the OP, though. The OP's alleged solution seems to contradict my statements above, but may be attributed to a misunderstanding on either side.