I/O (Input/Output) monitoring method

The invention is applicable to the technical field of computers, and provides an I/O (Input/Output) monitoring method. The I/O monitoring method comprises the steps of: 1.1 detecting the type of access to a port of a virtual hardware device; 1.2 when a client software module accesses to a PIO (Parallel Input/Output) port of the virtual hardware device, controlling the virtual machine monitor to intercept a read-write command sent from a user operating system to a CMD (Command) register, monitoring the operation condition of reading data from a data register, and when data is monitored to be read from the data register, returning the data to the operating system; and 1.3 when an MMIO (Memory-Mapped Input/Output) port of the virtual hardware device is accessed through a command analog module, controlling the virtual machine monitor to convert a physical address space to a real physical address space, and performing DMA (Direct Memory Access) data transmission between the virtual hardware device and an internal memory specified in a PRD (Physical Region Descriptor) table so as to realize the monitoring of the ports at the bottom layer of the device.