After upgrading to kernel 6.12, VirtualBox fails to start

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1

I installed system updates on my F41 machine yesterday, and now VirtualBox fails to start:

Failed to start the virtual machine Win11.

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).

Result Code:NS_ERROR_FAILURE (0x80004005)
Result Detail:-4011 (0xfffff055)
Component:ConsoleWrap
Interface:IConsole {6ac83d89-6ee7-4e33-8ae6-b257b2e81be8}

There’s already a bug report. Evidently, with kernel 6.12, kvm is enabled by default and this conflicts with VirtualBox.

My question for you Fedora folks, as I’m not well versed enough in kernel-ology:

Can I safely use the suggested work-arounds, or do I have to expect side effects?

  1. Either remove the kvm kernel module(s):

    modprobe -r kvm_intel

  2. Or modify the kernel command line by adding:

    kvm.enable_virt_at_load=0

Thanks.

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2

P.S. to myself: currently I got VirtualBox running after adding the kernel parameter.

Updated 18-Dec-2024: Use grubby as pointed out by @icher below

Original post:

sudo vim /etc/default/grub
# add kvm.enable_virt_at_load=0 to the line starting with GRUB_CMDLINE_LINUX
# then don't forget
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
# and reboot

Still I worry that I might have broken something without knowing yet…

1 Like
3

Problem with VirtualBox is when changing kernel it want to create new kernel modules.

How did you install the VirtualBox?

p.s.
Virt-Manager will not bother you with the kernel modules/headers. That it was the reason why I changed from Virtual-Box to virt-manager.

4

I added that line as well to grub and have not had any issues.I am guessing it is a work around until virtualbox releases there next version.Either way it does not affect anything other than lets virtualbox start with kernel 6.12.

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5

what are we adding to the line starting with GRUB_CMDLINE_LINUX Ask Fedora

you say the above line, but not sure what line you are refering to.

sorry this doesnt seem obvious to me.
Thanks.

6

You need to add kvm.enable_virt_at_load=0.

For example, in my grub file the line looks like this:

GRUB_CMDLINE_LINUX="resume=UUID=498514bc-996e-497c-b57b-0c4e3d444a5b rhgb quiet rd.driver.blacklist=nouveau modprobe.blacklist=nouveau kvm.enable_virt_at_load=0"

Caveat – don’t simply copy this line to your system! It may break. Only use the kvm.enable... part.

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tomporter@fedora:~$ sudo update-grub
[sudo] password for tomporter: 
sudo: update-grub: command not found
8
9

Sorry, my bad. update-grub is from my Ubuntu days, and I have ingrained this command so much that I first issued it on the command line myself, only to end up recommending it in this thread :-/

The correct command to update the grub configuration on Fedora is

sudo grub2-mkconfig -o /boot/grub2/grub.cfg

This is taken straight from my terminal’s history, so I hope it does work for you now as well :wink:

P.S. I edited my post above accordingly.

10

Just to add to what @bovender posted you can also use
sudo nano /etc/default/grub to edit the file then crtl x and save the changes.Myself I have never used vim and nano seems easier for me.

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11

You can use grubby as well:

# add kernel parameter
sudo grubby --update-kernel=ALL --args="kvm.enable_virt_at_load=0"

# remove kernel parameter
sudo grubby --update-kernel=ALL --remove-args="kvm.enable_virt_at_load=0"
11 Likes
12

I am new to Fedora/Linux and putting code into the terminal.

I tried the solution from @icher but it did not work for me.

I opened the terminal, copied and pasted:

sudo grubby --update-kernel=ALL --args="kvm.enable_virt_at_load=0"

Then I was prompted to put in my user password.

Then I put in the second line of code:

sudo grubby --update-kernel=ALL --remove-args="kvm.enable_virt_at_load=0"

I rebooted and tried again. I am still getting the same error message. Previously (some days ago) I had a pop up window like this:

screenshot
screenshot619×491 49.4 KB

More recently (the past couple of tries) I am just getting this error message in a side column within the VirtualBox window:

screenshot 2
screenshot 2361×254 21.2 KB

I am new to Linux, so maybe I put the code in wrong. I need very simple step by step instructions.

13

This is what worked for me. These are the commands you do. Now when you edit grub (the first step, it is not a simple copy and paste. You have to go to the line that starts with GRUB_CMDLINE_LINUX and put the kvm.enable_virt_at_load=0 at the end. I believe you leave a space from the last thing on the line. then save and exit. Then run the next command.

Here is an example of that line, BUT DO NOT COPY THIS EXACTLY. It just shows what it looks like after adding this to the end. You will have to look at your line, and add the kvm.enable_virt-at_load=0 to the end just like this example.

GRUB_CMDLINE_LINUX="resume=UUID=498514bc-996e-497c-b57b-0c4e3d444a5b rhgb quiet rd.driver.blacklist=nouveau modprobe.blacklist=nouveau kvm.enable_virt_at_load=0"

Ok. Now here are the commands you do.

sudo nano /etc/default/grub
# add kvm.enable_virt_at_load=0 to the line starting with GRUB_CMDLINE_LINUX
#CTRL-X will exit, and it will ask you to save, hit Y
# then don't forget
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
# and reboot

Now if it says nano is not found, you will have to do a

sudo dnf install nano

first

14

This added what was needed to get virtualbox to work.
sudo grubby --update-kernel=ALL --args=“kvm.enable_virt_at_load=0”
If you desided to remove it this will remove the line.
sudo grubby --update-kernel=ALL --remove-args=“kvm.enable_virt_at_load=0”
You need that first line to get virtualbox to work.

15

You ony run the first command to disable KVM

If for some reason you need KVM back, then you run the second line. Doing both like you did just added then removed it again, meaning no change. Only run the first command