VirtualBox giving me friction about AMD-V

This is more than a little annoying.  After upgrading my VirtualBox to version 3.1.6, it now decides that my cpu’s AMD-V is not operational.  Everything was fine previously, everyone played nice together.  Now it refuses to start my 64bit guests.

VirtualBox VT-x/AMD-V Error Message

VirtualBox VT-x/AMD-V error message after upgrading

After spending some times googling for a solution or a workaround, I think I have found an acceptable workaround.

Thanks to this link.

From what I have read, previous versions of VirtualBox ignored the VT-x/AMD-V setting on my motherboard.

I had two servers which were affected.

  Motherboard: Biostar TA790GX A2+
  CPU: AMD Phenom X4
  OS: Fedora 12
  Bios: Virtualization Enabled
  Motherboard: ASUS M3A78-EM
  CPU: AMD Athlon II X2 250
  OS: Ubuntu 9.10
  Bios: Virtualization Enabled

The workaround that I have found involves setting the following environment variable.


So I appended the following to my  /etc/profile.


I logged out and logged in again and now things appear to be fixed.  I am able to start and run my 64bit guests again.

UPDATE 05/08/2010:  Part II: VirtualBox is giving me friction about AMD-V


3 thoughts on “VirtualBox giving me friction about AMD-V

  1. Thank you so much.. I’ve the same mother board and VirtualBox was giving me same problem in Ubuntu 10.04 64-bit.. then I saw your guide, it helped me.. my sysconfig :-

    AMD Phenom II 720 BE
    Motherboard :- Biostar TA790GX BE
    3 GB DDR2 RAM

    Btw.. can you tell me which module to look in the BIOS to see if AMD-V is enabled? I checked enabled in “Secure Virtual machine” section under CPU configuration in BIOS.. it would clear any more doubts if you could tell me..

    • You have selected the right thing. For AMD cpus it is called SVM or “Secure Virtual Machine”. I wish I had a permanent resolution. Until then, I’m using this work around. If I learn more I’ll certainly post an update.

      BTW, do you have kvm kernel modules loaded? I am currently pursuing that angle for a root cause.

      $ sudo lsmod | grep kvm

      kvm_amd 36420 0
      kvm 286392 1 kvm_amd

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