[PATCH 0/7] KVM: arm64: PMU: Allow userspace to limit the number of PMCs on vCPU

[Marc Zyngier]

On Tue, 03 Jan 2023 12:40:34 +0000,
Jonathan Cameron <Jonathan.Cameron at Huawei.com> wrote:
> 
> On Thu, 29 Dec 2022 19:59:21 -0800
> Reiji Watanabe <reijiw at google.com> wrote:
> 
> > The goal of this series is to allow userspace to limit the number
> > of PMU event counters on the vCPU.
> 
> Hi Rieji,
> 
> Why do you want to do this?
> 
> I can conjecture a bunch of possible reasons, but they may not
> match up with your use case. It would be useful to have that information
> in the cover letter.

The most obvious use case is to support migration across systems that
implement different numbers of counters. Similar reasoning could also
apply to the debug infrastructure (watchpoints, breakpoints).

In any case, being able to decouple the VM from the underlying HW
within the extent that the architecture permits it seems like a
valuable goal.

Thanks,

	M.

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