Your Cylance Smart Antivirus subscription determines the number of devices installs allowed by your license. Each unique operating system will require the use of one device license. For example, if you have a dual boot Mac running Windows and macOS, you would need to use two of your licenses, one for each OS.
The same would apply if you are using VMWare or another virtualization platform. Each virtual machine (VM) instance would require an installation of Cylance Smart Antivirus and therefore will use one device license. VMs that are suspended or not running will still hold on to one license, just like a physical computer does when it is turned off. If you no longer need a VM, you can reclaim the license by uninstalling Cylance Smart Antivirus and removing this device in your Dashboard (https://mydashboard.cylance.com).