PAE/NX enabled, but NX (No-Execute Page Protection) still disabled

[Jan Ritzerfeld]

I created a Vista-VirtualBox (OSE) with the PAE/NX setting enabled. A few days ago, I noticed that hardware DEP is not available. In the VBox.log I see that PAE is enabled, but NX (No-Execute Page Protection) is disabled:

[...]
************************* CFGM dump *************************
  EnablePAE          <integer> = 0x0000000000000001 (1)
[...]
********************* End of CFGM dump **********************
CPUMSetGuestCpuIdFeature: Enabled PAE
Logical host processors: 2, processor active mask: 0000000000000003
************************* CPUID dump ************************
         RAW Standard CPUIDs
[...]
PAE - Physical Address Extension       = 1 (1)
[...]
         RAW Extended CPUIDs
[...]
PAE - Physical Address Extension       = 0 (0)
[...]
NX - No-Execute Page Protection        = 0 (1)

I did not find any helpful information about NX and VirtualBox, neither in the forums (NX is too short to search, DEP finds nothing) nor via google. So I do not even know whether DEP/NX is really supposed to work with VirtualBox (OSE) and Vista.

[Jan Ritzerfeld]

Still no luck with VirtualBox 3.1.2.

[Frank Mehnert]

The reason is that your guest doesn't use the PAE mode. Is it possible that you installed your Vista guest with PAE disabled and enabled the PAE setting later? If you installed your guest with PAE enabled then your guest doesn't use PAE for another reason.