On Wed, Apr 14, 2021 at 02:44:05PM +0100, Marc Zyngier wrote:
> KVM/arm64 is the sole user of perf_num_counters(), and really
> could do without it. Stop using the obsolete API by relying on
> the existing probing code.
>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
> arch/arm64/kvm/perf.c | 7 +------
> arch/arm64/kvm/pmu-emul.c | 2 +-
> include/kvm/arm_pmu.h | 4 ++++
> 3 files changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm64/kvm/perf.c b/arch/arm64/kvm/perf.c
> index 739164324afe..b8b398670ef2 100644
> --- a/arch/arm64/kvm/perf.c
> +++ b/arch/arm64/kvm/perf.c
> @@ -50,12 +50,7 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = {
>
> int kvm_perf_init(void)
> {
> - /*
> - * Check if HW_PERF_EVENTS are supported by checking the number of
> - * hardware performance counters. This could ensure the presence of
> - * a physical PMU and CONFIG_PERF_EVENT is selected.
> - */
> - if (IS_ENABLED(CONFIG_ARM_PMU) && perf_num_counters() > 0)
> + if (kvm_pmu_probe_pmuver() != 0xf)
Took me a while to figure out that this returns 0xf if the hardware has a
PMUVer of 0x0, so it's all good:
Acked-by: Will Deacon <will@xxxxxxxxxx>
Will
