message: add a warning for unsupported perfmon version in vm
diff: @@ -1428,6 +1428,10 @@ void PCM::printSystemTopology() const
  std::cerr << "Number of core PMU fixed counters: " << core_fixed_counter_num_max << "\n";
  std::cerr << "Width of fixed counters: " << core_fixed_counter_width << " bits\n";
  }
  + if (perfmon_version < 2 && vm == true)
  + {
  + std::cerr << "Warning: detected an unsupported virtualized environment: the hypervisor has limited the core PMU (perfmon) version to " << perfmon_version << "\n";
  + }
  }
  bool PCM::initMSR()
  