Gentoo Forums
Gentoo Forums
Gentoo Forums
Quick Search: in
Disable KVM Support for QEMU
View unanswered posts
View posts from last 24 hours

 
Reply to topic    Gentoo Forums Forum Index Kernel & Hardware
View previous topic :: View next topic  
Author Message
rralf
n00b
n00b


Joined: 10 Jun 2012
Posts: 9

PostPosted: Wed Dec 19, 2012 3:11 pm    Post subject: Disable KVM Support for QEMU Reply with quote

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!
Back to top
View user's profile Send private message
rralf
n00b
n00b


Joined: 10 Jun 2012
Posts: 9

PostPosted: Wed Dec 19, 2012 5:00 pm    Post subject: Reply with quote

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.
Back to top
View user's profile Send private message
Etal
Veteran
Veteran


Joined: 15 Jul 2005
Posts: 1783

PostPosted: Wed Dec 19, 2012 5:34 pm    Post subject: Reply with quote

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
-no-kvm-pit disable KVM kernel mode PIT
-no-kvm-pit-reinjection

_________________
“And even in authoritarian countries, information networks are helping people discover new facts and making governments more accountable.”– Hillary Clinton, Jan. 21, 2010
Back to top
View user's profile Send private message
Hu
Moderator
Moderator


Joined: 06 Mar 2007
Posts: 15969

PostPosted: Thu Dec 20, 2012 1:16 am    Post subject: Reply with quote

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.
Back to top
View user's profile Send private message
Display posts from previous:   
Reply to topic    Gentoo Forums Forum Index Kernel & Hardware All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum