US Patent 10095645 Presenting multiple endpoints from an enhanced PCI express endpoint device

A system that provides virtualized computing resources to clients or subscribers may include an enhanced PCIe endpoint device on which an emulation processor emulates PCIe compliant hardware devices in software. In response to receiving a transaction layer packet that includes a transaction directed to an emulated device, the endpoint device may process the transaction, which may include emulating the target emulated device. The endpoint device may include multiple PCIe controllers and may expose multiple PCIe endpoints to a host computing system. For example, each PCIe controller may be physically coupled to one of multiple host processor sockets or host server SOCs on the host computing system, each of which exposes its own root complex. Traffic received by the PCIe controllers may be merged on the endpoint device for subsequent processing. Traffic originating at one host processor socket may be steered to the PCIe controller to which it is directly attached.