Intel VT in VirtualBox on MacBook Pro for Linux/KVM

Discussion in 'Mac Apps and Mac App Store' started by marshallpd, Dec 27, 2008.

  1. marshallpd macrumors newbie

    Jun 18, 2008

    I have a (slightly) older MacBook Pro (2.16ghz, 4mb L2 cache, 667 FSB), which according to Intel contains their virtualization tech:

    I want to run a Linux VM and have the hypervisor export the VT to the VM so my Linux system can support KVM. I don't really want to do anything inside the KVM VM's other than do a basic boot so I can play around with / hack with KVM without having to powerdown OS X. I realize running a VM inside of a VM will be painfully slow.

    I've done this on Windows with Virtual Box and it seems to work fine. However, on the latest version of Virtual Box (and the previous version I was running before I just upgraded) the checkbox under the settings for a VM (Settings->General->Advanced) the Enable VT-x/AMD-V is greyed out and I can't check it.

    Does anyone know what I can do to fix this?

    UPDATE: I also have VMware Fusion, if anyone knows how to accomplish this same thing with that product, however, I haven't seen anything.

  2. mongrol macrumors regular

    Jul 16, 2007
    I don't know why the VT option is greyed out but even if it wasn't, I'd be very surprised if the guest OS had use of VT functions on the host processor. Virtualisation works on specific layers (rings) and the guest OS will never get ring 0 access where the VT stuff lives.
  3. marshallpd thread starter macrumors newbie

    Jun 18, 2008
    It's the x86 architecture that provides rings (privilege levels) for execution. The virtualization extensions were included to allow x86 instructions to be virtualized (so the appropriate instructions can be trapped, etc.). Thus, when VT was added it added another ring (-1) for the hypervisor (VMM), allowing the guest to execute in ring 0.

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