CN102567074A - USB (universal serial bus) device redirecting method facing virtual machines - Google Patents

Abstract

A virtual machine-oriented USB device redirection method. Including steps: (1) The virtual machine is created by the emulator QEMU on the remote physical machine B that has joined the USB device redirection system, and the local physical machine A accesses this virtual machine through the remote desktop protocol; (2) The physical machine where the USB device is located C uses the USB redirection protocol to realize the communication between the USB device and the virtual machine on the remote physical machine B; (3) The remote physical machine B redirects the USB device on the physical machine C to In the specified virtual machine on the remote physical machine B, so that the local physical machine A can use the USB device in the remote desktop. This method is applicable to all virtual machines created by using the emulator QEMU that has added the USB device redirection system to perform USB device redirection through the USB redirection protocol.

Description

A virtual machine-oriented USB device redirection method

technical field

The invention relates to a method for a virtual machine created by emulator QEMU to access a USB device on a local or remote physical machine, especially a method for specifying a USB device on a physical machine through a transmission control protocol socket (TCP Socket) and a USB redirection protocol. Method for redirecting USB devices to specified virtual machines.

Background technique

Virtualization (Virtualization) technology first appeared in the IBM mainframe system in the 1960s. With the widespread deployment of multi-core systems, clusters, grids, and even cloud computing in recent years, the advantages of virtualization technology in commercial applications have become increasingly evident, not only reducing IT costs, but also enhancing system security and reliability. The concept of virtualization It has also gradually penetrated into people's daily work and life. However, there are many problems in the process of using virtualization technology.

USB is a new type of serial interface. Compared with traditional interfaces, USB has many characteristics such as fast speed, independent power supply, plug and play, and low cost, and has a very wide range of applications. However, due to the various types of devices and complex communication protocol specifications, the design of USB device simulation software is cumbersome and difficult to develop. As we all know, USB devices such as printers, flash memory, mobile hard disks, and digital cameras are very important to users. However, there are still many problems in using virtual machines to access USB devices on local physical machines in existing virtualization technologies. For example, many open source virtualization technologies do not yet support access to USB devices, or only support a limited number of USB devices. access; while some commercial paid virtualization software supports USB devices better than open source virtualization software, but there are still some limitations. For example, Microsoft's virtual server (Hyper-V Server) and its own virtual machine (Virtual PC) do not yet support the access of USB devices. It is necessary to use third-party paid software such as network USB (USB Over Network) to use USB devices through the network. equipment. VMWare's desktop virtual machine can be configured to use various USB devices from the desktop. When using this feature, you can access most of the USB devices connected to the local client system from the client menu. However, the USB redirection function of VMWare's desktop virtual machine has the following limitations:

1. When you access the USB device from the client menu and use the device in the desktop, you will not be able to access the device on the local computer (only 1 access at the same time);

2. If you access the desktop from the browser portal, you can only use this function on the Windows client, and you need to have installed the component with optional USB redirection on the local Windows system in advance;

3. To use a USB printer on the desktop, the user must install the required print driver on the desktop.

VMware's free virtual machine still lacks support for USB redirection.

For using a virtual machine to access a USB device on a remote physical machine, whether it is an open source virtualization software or a commercial paid virtualization software, it is still a blank so far.

In order to reduce the development difficulty of the virtual machine, reduce system consumption, improve versatility, make full use of the existing driver, so that the virtual machine can access the USB device on the local or remote physical machine, research through the transfer control protocol socket and USB reload The method of combining targeted protocols is the best way, and it also has important practical significance.

Contents of the invention

Aiming at the limitations of open source and commercial paid virtualization software for accessing local USB devices, and the problem that accessing USB devices on remote physical machines has not yet been realized, the present invention proposes a virtual machine-oriented USB device redirection method.

Emulator QEMU is a platform virtualization solution that allows virtualization of a complete PC environment (including disks, graphics adapters and network devices). Any I/O requests generated by the guest operating system are intercepted and resent to user mode emulated by the QEMU process. This method is to add the redirection function of the USB device on the basis of the emulator QEMU, and communicate with the local or remote physical machine, so that the virtual machine created by the emulator QEMU can access the USB device on the local or remote physical machine .

In order to realize above-mentioned function, virtual machine USB redirection method provided by the present invention comprises the following steps:

1) Modify the emulator QEMU and add USB redirection function. Use this emulator QEMU to create a QEMU virtual machine, and any physical machine in the LAN can access the QEMU virtual machine on this physical machine through the remote desktop protocol;

2) Use the USB redirection protocol on the physical machine where the USB device is located to realize the communication between the USB device and the remote QEMU virtual machine;

3) The remote QEMU virtual machine redirects the USB device in step 2) to the virtual machine through command line commands.

Step 1) includes the following specific steps:

11) Define a structure used to represent a USB device that needs to be redirected;

12) Implement functions such as reading, writing, and querying to operate the structure;

13) A module for communicating with the remote host where the USB device is located;

14) Use the emulator QEMU with the USB redirection function to create a virtual machine and make a remote connection.

The specific process of step 12) is to first judge the specific type of data operation, and then execute the corresponding operation function according to the type of data operation.

In step 2), use the corresponding command line command to obtain the vendor ID and product identification code of the USB device that needs to be redirected, and start a server-side process of the USB device redirection protocol on the physical machine where the USB device is located, and then transfer a The port number is assigned to the vendor ID and product identification code of the USB device, and the port is monitored.

In step 3), first obtain the vendor ID and product identification code of the USB device and the IP address of the physical machine where it is located; then redirect the USB device to the remote end through command line commands in the monitor of the remote QEMU virtual machine In the QEMU virtual machine.

Then use the transmission control protocol socket established in step 2) and step 3) for data transmission.

The invention mainly includes two parts: USB redirection protocol and USB device redirection system based on emulator QEMU. Among them, the USB redirection protocol allocates a listening port for the USB device on the physical machine, and starts to listen to this port; at the same time, a transmission control protocol socket connection is established with the remote QEMU virtual machine; and then the remote QEMU virtual machine receives the USB device According to different operation types, perform corresponding operations on the USB device on the physical machine. The USB device redirection system based on the emulator QEMU redirects the USB device on the host with a given IP address to the QEMU virtual machine, then receives the operation of the USB device in the virtual machine through the remote desktop, and feeds back this operation to The physical machine where the USB device is located; after the physical machine where the USB device is located has processed the specified operation, the result is sent back to the virtual machine, and the virtual machine re-simulates the data processed by the physical machine where the USB device is located, and reproduces it in the virtual machine.

The technical effect of the present invention is that it solves the limitation of open source and commercial paid virtualization software on accessing local USB devices, and fills the gap that open source and commercial paid virtualization software cannot access USB devices on remote physical machines.

Description of drawings

Figure 1 is a schematic diagram of the architecture of USB device redirection;

FIG. 2 is a flow chart of the processing of the USB device redirection protocol.

Detailed ways

In order to make the features and advantages of the present invention more clearly understood, below in conjunction with accompanying drawings, describe in detail as follows: As shown in Figure 1, described framework of the present invention, access physical host B through the remote desktop protocol on physical host A At this time, the virtual machine on physical host B needs to access the USB device on physical host C (the USB device and USB redirection protocol on physical host C can also be located on physical host A), in this embodiment The specific execution steps are:

1) Use the emulator QEMU with the USB redirection function to create a virtual machine, and the physical machine A accesses the virtual machine on the physical machine B through the remote desktop protocol;

2) Use the USB device redirection protocol on physical machine C to realize the communication between the USB device on physical machine C and the virtual machine on physical machine B;

3) The virtual machine on physical machine B redirects the USB device on physical machine C to the virtual machine on physical machine B through command line commands.

4) Operate the USB device in the virtual machine on physical machine B through the remote desktop on physical machine A.

Step 1) The USB redirection function is added to the emulator QEMU, and a structure is used to represent a USB device that needs to be redirected; using the virtual machine created by this QEMU, QEMU will determine the current virtual machine configuration status and the USB device Operation types of different data types such as control stream data, file stream data, interrupt stream data, etc., and send these information beds to the physical host C where the USB device is located.

Step 2) In the command line, you need to use commands to obtain the vendor ID and product identification code of the USB device that needs to be redirected, and start a server-side process of the USB device redirection protocol on the physical machine C, and then set a port number The vendor ID and product identification code assigned to this USB device, and monitor this port. After the emulator QEMU in step 1) obtains the operation information of the virtual machine on the USB device redirected to it, it sends it to the physical host C through the USB redirection protocol. After processing, the physical host C feeds back the result to the emulator QEMU on the physical host B; and what is presented in the virtual machine is the processed result.

Step 3) First obtain the vendor ID and product identification code of the USB device and the IP address of the physical machine where it resides; then redirect the USB device of the local host to the remote virtual in the plane.

Step 4) Use the remote desktop on the local physical machine A to access the virtual machine on the remote physical machine B, and perform operations such as reading, writing, and deleting the USB design on the physical machine C redirected to this virtual machine, The operation type is fed back to the virtual machine on the physical machine B through the remote desktop protocol, and the physical machine B sends the corresponding operation to the physical machine C where the USB device is located through the connection established in step 2), and the physical machine C makes corresponding processing Finally, the results are sent to the virtual machine on physical machine B, and the corresponding results are also presented through the remote desktop on physical machine A.

USB redirection protocol among the present invention: this agreement is made up of following three parts:

1) USB device module usb-device: represents the USB device that needs to be redirected;

2) USB client module usb-guest: connect usb-device, and perform specified operations on usb-device;

3) USB server-side module usb-host: present usb-device to the remote virtual machine through the network, and make usb-device available to usb-guest.

This protocol runs a server-side USB redirection usbredirserver process on the physical machine C, and allocates a listening port for the USB device that needs to be redirected, and starts to listen to this port; at the same time, it is created by the emulator QEMU on the remote physical machine B The virtual machine establishes a transmission control protocol socket connection; then receives various operation requests for the USB device sent by the virtual machine, and after the physical machine C completes the corresponding processing of these requests, the result is fed back to the remote physical machine Virtual machine on B.

USB device redirection system based on emulator QEMU: modify emulator QEMU, add USB redirection connection usbredir-tcp module, responsible for connecting with usbredirserver process started by USB redirection protocol, and partially process information obtained from virtual machine or usbredirserver process , send the results to the appropriate section. Through the obtained USB device information and the IP address of the physical machine where the USB device is located, use the command line command to redirect the USB device on the physical machine C to the virtual machine created by the emulator QEMU on the physical machine B. On the physical machine A Use remote desktop to access the virtual machine on physical machine B, and perform operations on the USB device redirected to this virtual machine; after these operations are sent back to the virtual machine on physical machine B, physical machine B uses the USB device to redirect The system then sends it to the physical machine C where the USB device is located for corresponding processing.

The technical effect of the present invention is that it solves the limitation of open source and commercial paid virtualization software on accessing local USB devices, and fills the gap that open source and commercial paid virtualization software cannot access USB devices on remote physical machines.

Claims (7)

1. a virtual machine-oriented USB device redirection method, characterized in that: it includes Next steps: 1) The local physical machine A accesses the virtual machine on the remote physical machine B through the remote desktop protocol created by the emulator that has added the USB device redirection system; 2) Use the USB redirection protocol on the physical machine C where the USB device is located to realize the communication between the USB device and the virtual machine on the remote physical machine B; 3) The remote physical machine B redirects the USB device on the physical machine C to the specified virtual machine on the remote physical machine B through the command line command of the emulator; 4) The local physical machine A accesses the specified virtual machine on the remote physical machine B through the remote desktop, and the operation is redirected to the USB device on the physical machine C in this virtual machine. 2. The method according to claim 1, characterized in that: in the step 1), the virtual machine is created by using the emulator QEMU added with the USB device redirection system. 3. The method according to claim 1, characterized in that: the specific change in the step 1) is to add the method of connecting the physical machine where the USB device is located, and the judgment and processing of the data types involved in operating the USB device method. 4. The method according to claim 2, characterized in that: in said step 2), first Obtain the vendor ID and product identification code of the USB device on the physical machine C where the USB device is located; then use the USB redirection protocol to allocate a listening port for this USB device on the physical machine C, and run a server-side USB redirection usbredirserver The process starts to listen to this port; the virtual machine created by the emulator QEMU on the remote physical machine B establishes a transmission control protocol socket connection with the usbredirserver process on the physical machine C. 5. The method according to claim 2, characterized in that: in the step 3), first obtain the vendor ID and product identification code of the USB device on the physical machine C and the IP address of the physical machine C; In the monitor of the virtual machine created by the emulator QEMU on the remote physical machine B, the USB device on the physical machine C is redirected to the specified virtual machine on the remote physical machine B through command line commands. 6. The method according to claim 2, characterized in that: in the step 4), use remote desktop on the local physical machine A to access the virtual machine on the remote physical machine B, and redirect to this virtual machine The USB on the physical machine C in the machine is designed to perform read, write, and delete operations. The operation type is fed back to the virtual machine on the physical machine B through the remote desktop protocol, and the physical machine B will perform corresponding operations through the connection established in step 2). It is sent to the physical machine C where the USB device is located, and the physical machine C performs corresponding processing and sends the result to the virtual machine on the physical machine B, and the corresponding result is also presented through the remote desktop on the physical machine A. 7. The virtual machine-oriented USB device redirection method according to any one of claims 1-6, characterized in that: the application system comprises the following parts: USB redirection protocol, which consists of the following three parts: 1) USB device usb-device module: represents the USB device that needs to be redirected; 2) USB client usb-guest module: connect usb-device, and perform specified operations on usb-device; 3) USB server-side usb-host module: present the usb-device to the remote virtual machine through the network, and make the usb-device available to the usb-guest; This protocol runs a usbredirserver process on the physical machine C, and allocates a listening port for the USB device that needs to be redirected, and starts to listen to this port; at the same time, it establishes a virtual machine with the virtual machine created by the emulator QEMU on the remote physical machine B Transmission control protocol socket connection; then receive various operation requests for the USB device sent by the virtual machine, and after the physical machine C completes the corresponding processing of these requests, the result will be fed back to the virtual machine on the remote physical machine B ; USB device redirection system based on emulator QEMU: modify emulator QEMU, add USB redirection connection usbredir-tcp module, responsible for connecting with usbredirserver process started by USB redirection protocol, and partially process information obtained from virtual machine or usbredirserver process Finally, send the result to the corresponding part; through the obtained USB device information and the IP address of the physical machine where the USB device is located, use the command line command to redirect the USB device on the physical machine C to the emulator QEMU on the physical machine B. In the created virtual machine, use remote desktop on physical machine A to access the virtual machine on physical machine B, and perform operations on the USB device redirected to this virtual machine; these operations are sent back to the virtual machine on physical machine B Finally, the physical machine B uses the USB device redirection system to send it to the physical machine C where the USB device is located for corresponding processing.

Images