Method and system for supporting peripheral component interconnect (PCI) peer-to-peer access across multiple PCI host bridges within a data-processing system

摘要

A method for supporting peer-to-peer access across separate Peripheral Component Interconnect (PCI) host bridges within a data-processing system is described. In accordance with the method and system of the present invention, during an access request from a PCI device, a first determination is made as to whether or not the access request is for a system memory attached to a system bus. In response to a determination that the access request is not for a system memory attached to the system bus, another determination is made as to whether or not the access request is for a PCI device under the same PCI host bridge as the requesting PCI device. In response to a determination that the access request is not for a PCI device under the same PCI host bridge as the requesting PCI device, executing added protocols for the support of PCI peer-to-peer access request across separate PCI host bridges within the data-processing system.