Virtual switching method, related apparatus, and computer system

A data exchange method for use by a computing node, wherein the computing node comprises a hardware layer, a host running on the hardware layer, and a plurality of virtual machines (VMs) configured by the host, wherein the hardware layer comprises an input/output (I/O) device and a storage device, wherein the VMs comprise a first VM having a virtual switching function, and one or more second VMs, and wherein the method comprises:

• configuring, by a configuration and management module set in the host and an agent module set in the first VM or an agent module set in an Openflow controller in communication with the first VM, a port mapping table, wherein the port mapping table lists a virtual port number of the first VM that corresponds to the I/O device and a virtual port number of the first VM that corresponds to each second VM;
• receiving, by the first VM, a first message from a source node, wherein the first message instructs the first VM to handle a switch of data from the source node to a target node, wherein the first message does not contain the data, and wherein the source node is the I/O device or a second VM, and the target node is the I/O device or a second VM;
• forming, by the first VM, a second message according to an address of the target node contained in the data and the port mapping table;
• and
• sending, by the first VM, the second message to the target node through a virtual port corresponding to the target node, wherein the second message instructs the target node to acquire the data from the storage device of the hardware layer.