VME in Microsoft VPC
Posted: Wed Aug 15, 2007 2:39 am
Hi,
Does anyone know if MS VPC 'officially' does not support Virtual Mode extensions. I have just come across something odd while testing a virtual mode monitor where it GPFs on privileged instructions even with VME enabled. Bochs and Virtualbox (and a real PC!) work fine.
It just struck me as a bit odd because a) VPC runs Windows DOS boxes fine and b) I thought that with the virtualisation used by VPC, the guest processor has the same capabilities as the host and I am using a P4.
I am doing nothing more complex than:
where write_cr4 and read_cr4 are simple nasm functions.
Cheers,
Adam
[EDIT]Oh, and IOPL is 3![/EDIT]
Does anyone know if MS VPC 'officially' does not support Virtual Mode extensions. I have just come across something odd while testing a virtual mode monitor where it GPFs on privileged instructions even with VME enabled. Bochs and Virtualbox (and a real PC!) work fine.
It just struck me as a bit odd because a) VPC runs Windows DOS boxes fine and b) I thought that with the virtualisation used by VPC, the guest processor has the same capabilities as the host and I am using a P4.
I am doing nothing more complex than:
Code: Select all
write_cr4(read_cr4() | CR4_VME);
Cheers,
Adam
[EDIT]Oh, and IOPL is 3![/EDIT]