[0/2] KVM: arm64: EL2 PMU reset handling fixes

Message

Marc Zyngier Feb. 17, 2025, 11:24 a.m. UTC

Joey reports that some of his PMU tests do not behave quite as
expected:

- MDCR_EL2.HPMN is set to 0 out of reset

- PMCR_EL0.P should reset all the counters when written from EL2

These couple of patches attempt to remedy the situation. Note that
they have only been compile-tested.

Marc Zyngier (2):
  KVM: arm64: Fix MDCR_EL2.HPMN reset value
  KVM: arm64: Contextualise the handling of PMCR_EL0.P writes

 arch/arm64/kvm/pmu-emul.c | 21 ++++++++++++++++-----
 arch/arm64/kvm/sys_regs.c |  7 ++++++-
 2 files changed, 22 insertions(+), 6 deletions(-)

Comments

Joey Gouly Feb. 20, 2025, 10:44 a.m. UTC | #1

On Mon, Feb 17, 2025 at 11:24:10AM +0000, Marc Zyngier wrote:
> Joey reports that some of his PMU tests do not behave quite as
> expected:
> 
> - MDCR_EL2.HPMN is set to 0 out of reset
> 
> - PMCR_EL0.P should reset all the counters when written from EL2
> 
> These couple of patches attempt to remedy the situation. Note that
> they have only been compile-tested.
> 
> Marc Zyngier (2):
>   KVM: arm64: Fix MDCR_EL2.HPMN reset value
>   KVM: arm64: Contextualise the handling of PMCR_EL0.P writes
> 
>  arch/arm64/kvm/pmu-emul.c | 21 ++++++++++++++++-----
>  arch/arm64/kvm/sys_regs.c |  7 ++++++-
>  2 files changed, 22 insertions(+), 6 deletions(-)

I see you're discussing the API around this, but this does fix the PMU tests, so:

Tested-by: Joey Gouly <[e-mail]>