I could add a comment to all other users of kvm_s390_vcpu_start/stop like
/*
* no need to check the return value of vcpu_stop as it can only have
* an error for protvirt, but protvirt means user cpu state
*/
if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
kvm_s390_vcpu_stop(vcpu);
to make clear why we do not check the return everywhere
