According to one or more embodiments a logical virtual device may provide
the desired functionality using either a virtual device or a physical
device connected to a virtual machine. When the physical device is
available, a guest operating system executing on a virtual machine (VM)
can be instructed to utilize the physical device. When the VM is migrated
between hosts of different underlying hardware, or when the physical
device becomes unavailable, e.g., through dynamic reconfiguration or
reallocation of physical resources, the guest operating system can be
instructed to utilize the virtual device instead.