/dev/kvm permissions

[Andras Simon]

On 6/18/07, Richard W.M. Jones <rjones at redhat.com> wrote:
> Andras Simon wrote:
> > When starting qemu-kvm as an ordinary user, I get
> >
> > open /dev/kvm: Permission denied
> > Could not initialize KVM, will disable KVM support
> >
> > Does that mean that it should be run by root (scary!) or that
> > /dev/kvm's permissions should be fixed? If the latter, does a simple
> > chmod suffice, or should one tamper with udev rules?
>
> KVM allows the user opening the device to arbitrarily lock large amounts
> of RAM so that it can't be swapped.  That's normally something you don't
> want ordinary users to be doing ...

On the other hand, in the thread you pointed to, Avi Kivity says
"Running kvm as a nonprivileged user is a supported and recommended
way of working."

>
> http://thread.gmane.org/gmane.comp.emulators.kvm.devel/3770 has more
> information.
>
> (Thanks to Dan Berrange who helped me to answer this question).

Reading that discussion gives me the impression that it's best to
create a special kvm user and chmod /dev/kvm so that it can access it.

Thanks for the pointer!

Andras