Re: [PATCH] kvm: add capability for halt polling

[Jon Cargille]

On Mon, Apr 20, 2020 at 2:10 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
> On 20/04/20 20:47, Jon Cargille wrote:
> >> Is it safe to allow any value from userspace here or would it maybe make
> >> sense to only allow [0, global halt_poll_ns]?
> > I believe that any value is safe; a very large value effectively disables
> > halt-polling, which is equivalent to setting a value of zero to explicitly
> > disable it, which is legal.
>
> Doesn't a large value make KVM poll all the time?  But you could do that
> just by running "for (;;)" so there's no reason to limit the parameter.

Yes, I mis-spoke; apologies. A large number will cause KVM to poll for a
long time; as long as the thread can be preempted, we don't see any
problem with that.

Thanks,

Jon

>
> Paolo
>