Re: [RFC PATCH v3 20/21] KVM: x86/xen: Prevent runstate times from becoming negative

[David Woodhouse]

On Tue, 2024-08-20 at 11:08 -0400, Steven Rostedt wrote:
> On Tue, 20 Aug 2024 11:22:31 +0100
> David Woodhouse <dwmw2@xxxxxxxxxxxxx> wrote:
> 
> > On Thu, 2024-08-15 at 21:39 -0700, Sean Christopherson wrote:
> > > > +       vx->last_steal = run_delay;
> > > > +
> > > > +       /*
> > > > +        * If KVM clock time went backwards, stop updating
> > > > until it
> > > > +        * catches up (or the runstates are reset by
> > > > userspace).
> > > > +        */  
> > > 
> > > I take it this is a legitimate scenario where userpace sets KVM
> > > clock and then
> > > the runstates, and KVM needs to lend a hand because userspace
> > > can't do those two
> > > things atomically?  
> > 
> > Indeed. Will update the comment to make that more obvious.
> > 
> > Thanks for the rest of the review on this series. I'll go through
> > in
> > detail and update it, hopefully this week.
> 
> Hmm, is this related at all to this:
> 
>  
> https://lore.kernel.org/all/20240806111157.1336532-1-suleiman@xxxxxxxxxx/

No, but patch 21 in this same series is.

Attachment: smime.p7s
Description: S/MIME cryptographic signature