Method and system for device address translation for virtualization

• US 20070043928A1
• Filed: 08/19/2005
• Published: 02/22/2007
• Est. Priority Date: 08/19/2005
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Panesar, Kiran, Lantz, Philip
• Granted Patent: US 8,347,063 B2
• Time in Patent Office: Days
• US Class Current: 711/206
• CPC Class Codes: G06F 12/10 Address translation
• CPC Class Codes: G06F 2009/45579 I/O management, e.g. providing access to device drivers or storage
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects

Abstract

A method of improving USB device virtualization is proposed that allows giving virtual machines (VMs) direct access to USB devices with a combination hardware and software solutions. The USB host controller replaces device identifiers assigned by the VM with real device identifiers that are unique in the system. The real device identifiers are assigned by the VMM or the host controller.

Claims

1. A method for device address translation for virtualization of a device comprising:

replacing a virtual machine device identifier of the device with the corresponding real device identifier for the device.

2. The method of claim 1 wherein the virtual machine identifier and the virtual machine device identifier are used to index a table to determine the corresponding real device identifier.

3. The method of claim 1 wherein the virtual machine identifier and the virtual machine device identifier are combined to form the corresponding real device identifier.

4. The method of claim 1 wherein the replacing of the virtual machine device identifier is in a queue head.

5. The method of claim 1 wherein the replacing of the virtual machine device identifier is in a transfer descriptor.

6. The method of claim 1 wherein the device is a USB device.

7. The method of claim 2, where the table is populated by a host controller.

8. The method of claim 2, where the table is populated by VMM software.

9. The method of claim 3, where the combination is done by a host controller.

10. The method of claim 3, where the combination is done by VMM.

11. The method of claim 3, where the combination is done by a USB driver.

12. An article of manufacture comprising:

a machine-readable medium having a plurality of machine readable instructions, wherein when the instructions are executed by a system with a plurality of virtual machines, the instructions provide to populate a table for address translation for virtualization of a device;

attaching the device to the system;

reading the capabilities of the attached device; and

selecting one of the virtual machines to attach to the device.

13. The article of manufacture of claim 12 wherein the device is a USB device.

14. The article of manufacture of claim 13 wherein capabilities of the attached device are done by reading USB descriptors of the device.

15. An article of manufacture comprising:

a machine-readable medium having a plurality of machine readable instructions, wherein when the instructions are executed by a system with a plurality of virtual machines, the instructions provide to populate a table for address translation for virtualization of a device;

attaching the device to the system;

reading the capabilities of the attached device;

selecting one of the virtual machines to attach to the device;

attaching the device to a virtual host controller of the selected virtual machine;

assigning a device address; and

substituting a real device identifier for the virtual machine device identifier for a predetermined set address command.

16. The article of manufacture of claim 15 wherein the device is a USB device.

17. The article of manufacture of claim 16 wherein capabilities of the attached device are determined by reading USB descriptors of the device.

18. The article of manufacture of claim 16 wherein the device identifier is a USB device address.

19. A bus controller for a system with a plurality of virtual machines that facilitates device address translation for virtualization of a device by:

assigning a real device identifier for the device;

recording the virtual machine identifier, virtual machine device identifier, and real device identifier; and

replacing the virtual machine device identifier with the real device identifier for a data transfer operation.

20. The bus controller of claim 19 wherein the bus controller uses a hub device identifier for a split transaction.

21. The bus controller of claim 19 wherein the device is a USB device.

22. A method for device address translation for virtualization of a device comprising:

selecting a n number of bits from a m number of bits, wherein n is less than m and the m number of bits represent a real device identifier and the n number of bits represents the virtual machine identifier; and

the n−

m number of bits represents the virtualized device'"'"'s identifier as assigned by a virtual machine.

23. The method of claim 22 wherein the device is a USB device.

24. A bus controller for a system with a plurality of virtual machines that facilitates device address translation for virtualization of a device by:

determining the real device identifier for a data transfer by concatenating the virtual machine identifier and the virtual machine device identifier; and

replacing the virtual machine device identifier with the real device identifier.

25. The bus controller of claim 24 wherein the device is a USB device.

26. A bus controller for a system with a plurality of virtual machines that facilitates device address translation for virtualization of a device by:

modifying an identifier of the virtualized device in each packet that the host controller transmits; and

by replacing the virtual machine device identifier with the real device identifier in the packet.

27. The bus controller of claim 26 wherein the replacement of the virtual machine device identifier is in a queue head.

28. The bus controller of claim 26 wherein the replacement of the virtual machine device identifier is in a transfer descriptor.

29. The bus controller of claim 26 wherein the device is a USB device.

30. The bus controller of claim 26 wherein the device is a USB hub.

31. A computer system comprising:

one or more processors;

memory;

a bus;

one or more virtual machines with one or more virtualized devices; and

a bus controller which modifies the address of the virtualized device in each packet that the bus controller transmits by replacing the virtual machine device identifier with the real device identifier in the packet.

32. The system of claim 31 wherein the replacement of the virtual machine device identifier is in a queue head of a packet.

33. The system of claim 31 wherein the replacement of the virtual machine device identifier is in a transfer descriptor.

34. The system of claim 31 wherein the device is a USB device.

35. The system of claim 31 wherein the device is a USB hub.

36. A method for device address translation for virtualization of a device comprising:

replacing a VM device ID with a real device ID in response to a predetermined command and populating a translation table;

looking up the VM device ID in a transfer descriptor and a virtual machine identifier (VMID) in the translation table during a data transfer;

replacing the VM device ID with the real device ID from the translation table in the data transfer.

37. The method of claim 36 wherein the predetermined command is a set address command.

38. The method of claim 36 wherein a VMM or a host controller performs the replacement of the VM device ID.

39. The method of claim 36 wherein the host controller looks up the VMID and the VM device ID of a hub in the translation table and uses the real device ID of the hub from the translation table for split transactions.