bug#22633: Provide a kvm-less qemu / guix system vm

[Christopher Allan Webber]

Leo Famulari writes:

> On Fri, Feb 12, 2016 at 09:50:09AM +1100, Jookia wrote:
>> On Thu, Feb 11, 2016 at 09:26:12AM -0800, Christopher Allan Webber wrote:
>> > So on my Libreboot-enabled machine, KVM does not work.  In fact, even
>> > starting qemu with KVM enabled on it appears to crash my whole system.
>> > Not only does "guix system vm" not work, even "guix system vm-image" can
>> > take the whole machine down!
>> 
>> Currently the 'solution' I've found is to edit Guix to remove the two 
>> instances
>> of '--enable-kvm' which works somewhat, though it's slower as there's 
>> absolutely
>> no acceleration.
>> 
>> > It would be nice to have a --no-kvm switch, because I'd really like to
>> > make use of Guix's nice VM features!
>
> It's not a proper fix, but this patch achieves that on my non-Libreboot
> machine. Can you see if it works for you?
>
> [...]

Good news there, that does work and I am able to boot a VM through that
route!

I would really like to be able to protect myself from accidentally
crashing my system by making sure that if /dev/kvm is not there that we
don't do --enable-kvm, so maybe I could do that if we can figure out how
to make blacklisting actually work.  In the meanwhile, maybe I should
add a --no-kvm flag to "guix system vm"?