Re: [PATCH] KVM: x86: vPMU: truncate counter value to allowed width

[Sean Christopherson]

On Fri, Jun 30, 2023, Roman Kagan wrote:
> On Thu, Jun 29, 2023 at 05:11:06PM -0700, Sean Christopherson wrote:
> > @@ -74,6 +74,14 @@ static inline u64 pmc_read_counter(struct kvm_pmc *pmc)
> >         return counter & pmc_bitmask(pmc);
> >  }
> > 
> > +static inline void pmc_write_counter(struct kvm_pmc *pmc, u64 val)
> > +{
> > +       if (pmc->perf_event && !pmc->is_paused)
> > +               perf_event_set_count(pmc->perf_event, val);
> > +
> > +       pmc->counter = val;
> 
> Doesn't this still have the original problem of storing wider value than
> allowed?

Yes, this was just to fix the counter offset weirdness.  My plan is to apply your
patch on top.  Sorry for not making that clear.