KVM & VMX root mode

Sander van Leeuwen
2007-08-31T13:02:14Z

Hi,

We have had several reports of users saying our product VirtualBox
crashes their (Linux) host. It turned out that KVM is responsible, because
it leaves the CPU in VMX root mode.

Doing this changes the way the cpu operates: updates to reserved bits in
control registers cause general protection faults.
We hit such cases on two occasions; clearing the X86_CR4_VMXE bit in CR4
and turning off paging.

I have added a workaround to detect VMX root mode, simply refuse to run
and recommend that the user disables KVM.
I would however appreciate if you could fix KVM instead.

--
Kind regards / mit freundlichen Gruessen / Met vriendelijke groet
Sander van Leeuwen

innoTek GmbH
http://www.innotek.de
Germany