Re: VMX ideas

Alexander Graf
2008-10-29T17:18:52Z

On 29.10.2008, at 16:36, Gerd Hoffmann wrote:

> Alexander Graf wrote:
>> So I was thinking hard on what to do to circumvent this problem and
>> came
>> up with several approaches:
>
>> 3. Create a root mode bloat framework
>
> 4. Enter vmx root mode when the first user opens /dev/kvm and leave it
> when nobody uses it any more?
>
> Also note that there has been some discussion on lkml to move vmx-root
> on/off out of the kvm module into the kernel. There are a few places
> where it would be useful for the kernel to handle that without the kvm
> module being involved, crashdump kexec for example. With that and
> some
> locking in place (so only one can use vmx-root at a time) and
> hypervisors being friendly to each other and grab vmx-root only when
> they have a guest to run we should be set?

If we simply enter/exit VT root mode on kvm starts/stops every single
hypervisor would still have to maintain all the interaction bits
itself, like "Is this CPU VT capable?", "May I run VT here?", hotplug
events, suspend/resume, reboot, etc. It would help to have one place
to keep all of that, so suspend doesn't magically break when using
VMware vs. KVM.

That's basically the reason I didn't even propose 4. :-). If you think
that's a good solution, feel free to convince me.

Alex