VirtualBox Error: Unable to Operate in VMX Root Mode - Disable KVM Kernel Extension
If you've recently encountered an error while trying to use VirtualBox, which states that it can't operate in VMX root mode and suggests disabling the KVM kernel extension, recompiling the kernel, and rebooting (VERR\_VMX\_IN\_VMX\_ROOT\_M...), you're not alone. This article will provide a detailed explanation of the issue and offer solutions to help you resolve it.
Understanding the Error
The error is related to VirtualBox's inability to use VMX root mode due to the presence of the KVM kernel extension. VMX (Virtual Machine eXtensions) is a technology used by virtualization software, such as VirtualBox and VMware, to create and manage virtual machines. The KVM (Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware. It's integrated into the Linux kernel, providing a simple and efficient virtualization solution.
When both VirtualBox and KVM are installed on the same system, they can interfere with each other, causing issues like the one you've encountered. VirtualBox may not be able to operate in VMX root mode because KVM has already taken control of the virtualization capabilities of the CPU.
Resolving the Error
To resolve this issue, you'll need to disable the KVM kernel extension, recompile the kernel, and reboot your system. Here's a step-by-step guide to help you through the process:
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First, you need to disable the KVM kernel module. To do this, open a terminal and run the following command:
sudo rmmod kvm -
Next, you'll need to recompile the kernel with the KVM module removed. This process can be time-consuming, so make sure you have enough time to complete it. Here's how to do it:
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Backup your current kernel configuration file:
sudo cp /boot/config-`uname -r` /boot/config-custom -
Edit the kernel configuration file:
sudo nano /boot/config-custom -
Search for the KVM options and ensure they are disabled. For example, look for the following options and make sure they are set to 'N':
CONFIG_KVM=nCONFIG_KVM_INTEL=nCONFIG_KVM_AMD=n
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Save and close the configuration file.
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Now, compile the kernel:
sudo make -j `nproc` -
Once the kernel is compiled, install it:
sudo make modules_install install -
Update the GRUB bootloader:
sudo update-grub
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Finally, reboot your system using the new kernel:
sudo reboot
Additional Solutions
If disabling KVM and recompiling the kernel doesn't solve the issue, consider the following alternatives:
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Use a different virtualization platform, such as VMware or QEMU.
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Create a separate boot entry with the 'noexec' parameter for the KVM module, allowing you to boot your system without KVM when needed.
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If you need to use both VirtualBox and KVM, consider using a containerization solution like Docker or LXC instead of virtualization.
References
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VirtualBox Manual: https://www.virtualbox.org/manual/
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KVM Documentation: https://www.linux-kvm.org/page/Documentation
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Linux Kernel Compilation Guide: https://www.kernel.org/doc/html/latest/kbuild/kbuild.html
By following the steps outlined in this article, you should be able to resolve the VirtualBox error related to VMX root mode and KVM kernel extension interference. If you still encounter issues, consider exploring the alternative solutions provided or seeking help from the VirtualBox and KVM communities.