On Fri, Jun 30, 2023 at 07:28:29AM -0700, Sean Christopherson wrote:
> 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.
Ah, got it, thanks!
Also I'm now chasing a problem that we occasionally see
[3939579.462832] Uhhuh. NMI received for unknown reason 30 on CPU 43.
[3939579.462836] Do you have a strange power saving mode enabled?
[3939579.462836] Dazed and confused, but trying to continue
in the guests when perf is used. These messages disappear when
9cd803d496e7 ("KVM: x86: Update vPMCs when retiring instructions") is
reverted. I haven't yet figured out where exactly the culprit is.
Thanks,
Roman.
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