From: Like Xu<likexu@xxxxxxxxxxx>
Fix the following positive warning:
=============================
WARNING: suspicious RCU usage
arch/x86/kvm/pmu.c:190 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
1 lock held by CPU 28/KVM/370841:
#0: ff11004089f280b8 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x87/0x730 [kvm]
Call Trace:
<TASK>
dump_stack_lvl+0x59/0x73
reprogram_fixed_counter+0x15d/0x1a0 [kvm]
kvm_pmu_trigger_event+0x1a3/0x260 [kvm]
? free_moved_vector+0x1b4/0x1e0
complete_fast_pio_in+0x8a/0xd0 [kvm]
[...]
Fixes: 66bb8a065f5a ("KVM: x86: PMU Event Filter")
It's possible to call KVM_SET_PMU_EVENT_FILTER ioctl with the vCPU running.
Similar to "kvm->arch.msr_filter", KVM should guarantee that vCPUs will
see either the previous filter or the new filter so that guest pmu events
with identical settings in both the old and new filter have deterministic
behavior.