Re: [PATCH v1 0/5] target/arm/kvm: Provide an option to adjust virtual time

[Andrew Jones]

On Tue, Dec 10, 2019 at 03:21:02PM +0100, Andrea Bolognani wrote:
> On Tue, 2019-12-10 at 14:32 +0100, Andrew Jones wrote:
> > After having done this git mining, it looks more and more like we should
> > at least consider naming this feature 'kvm-no-adjvtime' and probably
> > also change arm's default.
> 
> I agree with everything except the naming: why would
> 
>   kvm-no-adjvtime=off  vtime is adjusted      (default)
>   kvm-no-adjvtime=on   vtime is not adjusted
> 
> be better than
> 
>   kvm-adjvtime=on   vtime is adjusted      (default)
>   kvm-adjvtime=off  vtime is not adjusted
> 
> ? Both offer the exact same amount of flexibility, but the latter has
> the advantage of not introducing any unwieldy double negatives.
>

A default of 'off' == 0 means not setting anything at all. There's
already precedent for 'kvm-no*' prefixed cpu features,

kvm-no-smi-migration
kvm-nopiodelay

(Unless there's something called a 'nopio' then I guess that one is
missing a -, but whatever...)

Thanks,
drew