Re: [PATCH v7 15/20] perf: arm_pmuv3: Handle IRQs for Partitioned PMU guest counters

[Colton Lewis]

wuyifan <wuyifan50@xxxxxxxxxx> writes:

> Hi Colton,

> On 5/5/2026 5:18 AM, Colton Lewis wrote:
> >    static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu)
> >    {
> > -	u64 pmovsr;
> >    	struct perf_sample_data data;
> >    	struct pmu_hw_events *cpuc = this_cpu_ptr(cpu_pmu->hw_events);
> >    	struct pt_regs *regs;
> > +	u64 host_set = kvm_pmu_host_counter_mask(cpu_pmu);
> > +	u64 pmovsr;
> kvm_pmu_host_counter_mask() is called from armv8pmu_handle_irq(). This
> interrupt fires in both host and guest contexts.

> However, kvm_pmu_host_counter_mask() dereferences
> host_data_ptr(nr_event_counters). This indirection requires
> kvm_arm_hyp_percpu_base[cpu] to be initialized, which only happens during
> KVM hypervisor setup. When the interrupt fires in a guest kernel where
> KVM is
> compiled but not active, the per-CPU base is NULL and the dereference
> faults.

I will fix that.


> Thanks,
> Yifan