Access proxy for accessing peripheral component interconnect express endpoint device, PCIe exchanger and computer system

A peripheral component interconnect express (PCIe) exchanger, wherein the PCIe exchanger applies to a computer system, wherein the computer system comprises a processor and a PCIe bus, wherein the PCIe bus connects to at least one PCIe endpoint device, wherein an upstream port of the PCIe exchanger connects to the processor through the PCIe bus and a downstream port of the PCIe exchanger connects to the PCIe endpoint device through the PCIe bus, wherein the PCIe exchanger further comprises an access proxy, wherein the access proxy is implemented by a direct memory access (DMA) engine, and wherein the DMA engine configured to:

• receive a data migration request for accessing the PCIe endpoint device from the processor;
• return a response message of the data migration request to the processor before performing data migration;
• and
• migrate, according to the data migration request, data in a memory of the PCIe engine to a memory of the computer system, or migrate data in the memory of the computer system to the memory of the PCIe endpoint device.

A computer system, wherein the computer system comprises:

• a processor;
• and
• a peripheral component interconnect express (PCIe) bus,
• wherein the PCIe bus connects to at least one PCIe endpoint device,
• wherein an access proxy is implemented by a direct memory access (DMA) engine,
• wherein the DMA engine connects to the processor and the PCIe endpoint device, and
• wherein the DMA engine is configured to:
• receive a data migration request-for accessing the PCIe endpoint device from the processor;
• return a response message of the data migration request to the processor before performing data migration;
• and
• migrate, according to the data migration request, data in a memory of the PCIe engine to a memory of the computer system, or migrate data in the memory of the computer system to the memory of the PCIe endpoint device.