# Disable KVM Support for QEMU

## rralf

Hi!

Is it possible to disable KVM support for qemu? My system doesn't support VT, so i don't need and want KVM.

When trying to start my VM, qemu complains:

# qemu-kvm

Could not access KVM kernel module: No such file or directory

failed to initialize KVM: No such file or directory

No accelerator found!

# qemu-system-x86_64                                                                                                                                                                                                                                                         1

Could not access KVM kernel module: No such file or directory

failed to initialize KVM: No such file or directory

No accelerator found!

There's no useflag KVM for qemu, so how may i disable it?

Thanks in advance!

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## rralf

Got the solution:

There's a (undocumented) -no-kvm CMDline switch.

In my opinion, there should be a KVM useflag for qemu, being disabled at default.

kvm should be opt-in.

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## Etal

Not exactly undocumented...

 *Quote:*   

> $ qemu-kvm --help | grep no-kvm
> 
> -no-kvm         disable KVM hardware virtualization
> 
> -no-kvm-irqchip disable KVM kernel mode PIC/IOAPIC/LAPIC
> ...

 

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## Hu

 *rralf wrote:*   

> In my opinion, there should be a KVM useflag for qemu, being disabled at default.
> 
> kvm should be opt-in.

 I disagree.  Most CPUs sold these days have support for VT-x / SVM, so disabling it by default because some users cannot use it is overkill.  If there are specific libraries that are only used when KVM is enabled, then a USE flag might be appropriate, but it should still default to enabling KVM unless the system administrator sets otherwise.

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