Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

How to disabling a particular instruction set in VirtualBox?

A modern host computer should have the latest instruction set, such as AVX.

I want to emulate the situation without AVX in the guest OS, so I want to disable AVX instruction set in the VM.

share|improve this question
    
Haven't played any with VirtualBox, but qemu (and Bochs) allow you to specify the CPU model (somewhat). –  vonbrand Feb 9 '13 at 23:18
add comment

1 Answer

VirtualBox does not support that.

If you're running Linux, there exists a patch to remove the features:

"Clear AVX, AVX2 features along with clearing XSAVE feature bits, as part of the parsing 'noxsave' parameter." https://patchwork.kernel.org/patch/1521191/

share|improve this answer
    
Need to patch and compile kernel? so complicated –  linquize Feb 12 '13 at 11:52
    
It may be possible to do a symlink hack with /proc/cpuinfo by mounting /proc somewhere else and symlinking everything into /proc except cpuinfo, where you take a file copy and remove the flags by hand. I have no idea if that will work, though. I don't know of a simple way to do this. –  larstobi Feb 12 '13 at 11:58
    
It seems that the patch referenced above made it to the 3.7 Linux release. So if you're running that kernel or later, you should have the patch already, and can invoke the mode by the "noxsave" parameter to the kernel in GRUB. –  larstobi Feb 12 '13 at 12:11
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.