High-performance input-output devices supporting scalable virtualization

A non-transitory machine-readable storage media having instructions which, when executed by one or more processors of an electronic device, cause the electronic device to provide scalable virtualization of an Input/Output (I/O) device coupled with the electronic device and perform operations comprising:

• composing a virtual device that comprises one or more assignable interface (AI) instances of a plurality of AI instances of a hosting function exposed by the I/O device, wherein
• the virtual device is to be utilized by a guest that is executed by the electronic device,
• wherein the plurality of AI instances can be independently assigned to guests via virtual devices to provide I/O device functionality to the guests;
• emulating device resources of the I/O device via the virtual device;
• intercepting a request from the guest pertaining to the virtual device;
• determining whether the request from the guest is a fast-path operation to be passed directly to one of the one or more AI instances of the I/O device or a slow-path operation that is to be at least partially serviced via software executed by the electronic device;
• and
• responsive to determining that the request is a slow-path operation, servicing the request at least partially via the software executed by the electronic device instead of passing the request to the I/O device directly from the guest.