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Thread: running KVM and VirtualBox at same host

  1. #1
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    running KVM and VirtualBox at same host

    Hi Guys,

    It's really funny. I have searched by google and found many issues said that kvm and VB cannot running at the same machine. On one discussing at VB's forum, the answer is "INPOSSIBLE".

    But I have two machines now running both of them. The first machine is use AMD 7960 CPU and the second AMD 945. On the first machine, the host is Ubuntu server 10.04, upgraded from 9.10. and it have 5 kvm guest running, 3 ubuntu servers, 2 windows servers. AND, it have a VirtualBox guest running also. I used one VirtualBox guest because it hve better support for USB devices. The second machine have similar situation. Both machines have been running well for almost a year!

    Last month, I bought a new machine. This time, I have a Intel i7 930 CPU. But this time when I try to running both VB and KVM, problem happened as many of people have seen. When I trying to start a VB guest, I got below error:
    Error: failed to start machine. Error message: VirtualBox can't operate in VMX root mode. Please disable the KVM kernel extension, recompile your kernel and reboot (VERR_VMX_IN_VMX_ROOT_MODE)

    If if remove the kvm_intel module by below command or blacklisted it as boot:
    # modprobe -r kvm_intel
    The VB guest can start but KVM guest will not!

    Someone said to disable the VM support at bios maybe will help. I will try it later. I will let you know the result.

    Do you have any lights?

    Bill
    Last edited by billdeng; November 10th, 2010 at 10:23 AM.

  2. #2
    Join Date
    Jan 2009
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    Re: running KVM and VirtualBox at same host

    Hi Guys,

    I find out something close to "why" and the solution. Hope be help for those still struggling.

    KVM has two hypervisor mode (or virtualization management). One is qemu and another is KVM. When kvm_intel (or kvm_amd) is not loaded, KVM can still work on QEMU mode. But qemu alone seems much less effective then kvm. In this case, both KVM and VB can run at same time.

    But in my previous machines, the kvm_amd module is loaded and VB still running well.

    I am really confused.

    Bill

  3. #3
    Join Date
    Feb 2005
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    Melbourne, Australia
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    Distro
    Ubuntu 12.04 Precise Pangolin

    Re: running KVM and VirtualBox at same host

    Quote Originally Posted by billdeng View Post
    Hi Guys,

    I find out something close to "why" and the solution. Hope be help for those still struggling.

    KVM has two hypervisor mode (or virtualization management). One is qemu and another is KVM. When kvm_intel (or kvm_amd) is not loaded, KVM can still work on QEMU mode. But qemu alone seems much less effective then kvm. In this case, both KVM and VB can run at same time.

    But in my previous machines, the kvm_amd module is loaded and VB still running well.

    I am really confused.

    Bill
    So something that works with one CPU family doesn't work with a different CPU family - where the CPUs are different designs with different capabilities and have totally different ways of supporting Virtulization.

    See the theme here?
    Regards, David.
    Please use the Forum search and Wiki search for immediate help
    Please mark your thread as Solved when appropriate
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  4. #4
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    Re: running KVM and VirtualBox at same host

    Thanks David, I know the CPU architecture is the main difference here.

    But I am not sure whether it is the only reason to the different results.

  5. #5
    Join Date
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    Distro
    Ubuntu 12.04 Precise Pangolin

    Re: running KVM and VirtualBox at same host

    Quote Originally Posted by billdeng View Post
    Thanks David, I know the CPU architecture is the main difference here.

    But I am not sure whether it is the only reason to the different results.
    If you look at the various CPU specs you see a lot of difference in Virtualization support and architecture. The VM platform providers have to use what is available in the CPUs as well as write code to get around what one CPU may do directly versus another CPU where they may have to emulate the functionality and some things may allow more capabilities than others.

    The inherent setup of your AMD CPUs may have allowed both modes to run compared to the Intel CPU - and there are various different VM capabilities in different CPU families from each manufacture as well.

    Sometime you just gotta accept that things work differently because things are different.
    Regards, David.
    Please use the Forum search and Wiki search for immediate help
    Please mark your thread as Solved when appropriate
    New to technical forums?: How To Ask Questions The Smart Way

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