Single Root I/O Virtualization (SR-IOV) is a PCIe extended capability which
makes one physical device appear as multiple virtual devices. The physical
device is referred to as Physical Function (PF) while the virtual devices are
referred to as Virtual Functions (VF).
Allocation of VF can be dynamically controlled by the PF via registers encapsulated in the capability. By default, SR-IOV is disabled and the PF behaves as a regular PCIe device. Once it is turned on, each VF's PCI configuration space can be accessed by its own bus, slot and function number (Routing ID). Each VF also has a PCI memory space, which is used to map its register set.A VF device driver operates on the register set so it can be functional and appear as a real PCI device.
At the moment, WinDriver only supports SR-IOV in Linux.