Re: [kvm-unit-tests PATCH v4 0/4] arm: pmu: Fixes for bare metal

[Marc Zyngier <maz@kernel.org>]

Hi Drew,

On Fri, 28 Oct 2022 12:40:41 +0100,
Andrew Jones <andrew.jones@linux.dev> wrote:
> 
> On Thu, Aug 11, 2022 at 11:52:06AM -0700, Ricardo Koller wrote:
> > There are some tests that fail when running on bare metal (including a
> > passthrough prototype).  There are three issues with the tests.  The
> > first one is that there are some missing isb()'s between enabling event
> > counting and the actual counting. This wasn't an issue on KVM as
> > trapping on registers served as context synchronization events. The
> > second issue is that some tests assume that registers reset to 0.  And
> > finally, the third issue is that overflowing the low counter of a
> > chained event sets the overflow flag in PMVOS and some tests fail by
> > checking for it not being set.
> > 
> > Addressed all comments from the previous version:
> > https://lore.kernel.org/kvmarm/YvPsBKGbHHQP+0oS@google.com/T/#mb077998e2eb9fb3e15930b3412fd7ba2fb4103ca
> > - add pmu_reset() for 32-bit arm [Andrew]
> > - collect r-b from Alexandru
> > 
> > Thanks!
> > Ricardo
> > 
> > Ricardo Koller (4):
> >   arm: pmu: Add missing isb()'s after sys register writing
> >   arm: pmu: Add reset_pmu() for 32-bit arm
> >   arm: pmu: Reset the pmu registers before starting some tests
> >   arm: pmu: Check for overflow in the low counter in chained counters
> >     tests
> > 
> >  arm/pmu.c | 72 ++++++++++++++++++++++++++++++++++++++++++-------------
> >  1 file changed, 55 insertions(+), 17 deletions(-)
> >
> 
> Hi all,
> 
> Please refresh my memory. Does this series work on current platforms? Or
> was it introducing new test failures which may be in the test, as opposed
> to KVM? If they work on most platforms, but not on every platform, then
> have we identified what triggers them to fail and whether that should be
> fixed or just worked-around? I'm sorry I still can't help out with the
> testing as I haven't yet had time to setup the Rpi that Mark Rutland gave
> me in Dublin.

This series does show that KVM is buggy, and I have patches out to fix
it [1]. The patches should work on anything, really.

> I know this series has been rotting on arm/queue for months, so I'll be
> happy to merge it if the consensus is to do so. I can also drop it, or
> some of the patches, if that's the consensus.

I'd be very happy to see these patches being merged.

Thanks,

	M.

[1] https://lore.kernel.org/r/20221028105402.2030192-1-maz@kernel.org

-- 
Without deviation from the norm, progress is not possible.
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