DIRECT ACCESS TO A HARDWARE DEVICE FOR VIRTUAL MACHINES OF A VIRTUALIZED COMPUTER SYSTEM

• US 20080294808A1
• Filed: 05/21/2008
• Published: 11/27/2008
• Est. Priority Date: 05/23/2007
• Status: Active Grant

• Current Assignee: Vmware LLC (Broadcom, Inc.)
• Original Assignee: VMware, Inc. (Broadcom, Inc.)
• Inventors: Nelson, Michael, Mahalingam, Mallik
• Granted Patent: US 8,527,673 B2
• Time in Patent Office: Days
• US Class Current: 710/26
• CPC Class Codes: G06F 12/0653 with centralised address assignment
• CPC Class Codes: G06F 13/105 where the programme performs an input/output emulation function
• CPC Class Codes: G06F 13/24 using interrupt G06F13/32 takes precedence
• 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

In a virtualized computer system in which a guest operating system runs on a virtual machine of a virtualized computer system, a computer-implemented method of providing the guest operating system with direct access to a hardware device coupled to the virtualized computer system via a communication interface, the method including: (a) obtaining first configuration register information corresponding to the hardware device, the hardware device connected to the virtualized computer system via the communication interface; (b) creating a passthrough device by copying at least part of the first configuration register information to generate second configuration register information corresponding to the passthrough device; and (c) enabling the guest operating system to directly access the hardware device corresponding to the passthrough device by providing access to the second configuration register information of the passthrough device.

Claims

1. In a virtualized computer system in which a guest operating system runs on a virtual machine of a virtualized computer system, a computer-implemented method of providing the guest operating system with direct access to a hardware device coupled to the virtualized computer system via a communication interface, the method comprising:

obtaining first configuration register information corresponding to the hardware device, the hardware device connected to the virtualized computer system via the communication interface;

creating a passthrough device by copying at least part of the first configuration register information to generate second configuration register information corresponding to the passthrough device; and

enabling the guest operating system to directly access the hardware device corresponding to the passthrough device by providing access to the second configuration register information of the passthrough device.

2. The method of claim 1, further comprising:

receiving an input/output (I/O) request from the guest operating system with a first guest physical address corresponding to the passthrough device;

mapping the first guest physical address to a first machine address corresponding to the hardware device;

performing an I/O operation with the first machine address; and

the guest operating system performing a subsequent I/O operation with a second guest physical address directly without mapping the second guest physical address to a second machine address.

3. The method of claim 1, further comprising:

receiving an input/output (I/O) request from the guest operating system with a first guest physical address corresponding to the passthrough device; and

performing a proxy I/O operation with a first machine address corresponding to the first guest physical address.

4. The method of claim 1, further comprising:

receiving an input/output (I/O) request from the guest operating system with a guest physical address corresponding to the passthrough device;

mapping the guest physical address to a machine address; and

performing a DMA operation with the machine address.

5. The method of claim 1, further comprising:

receiving an input/output (I/O) request from the guest operating system with a guest physical address corresponding to the passthrough device;

mapping the guest physical address to a machine address and providing the machine address to the guest operation system, and

the guest operating system generating the I/O request directly to the hardware device with the guest physical address replaced by the machine address.

6. The method of claim 1, further comprising:

the guest operating system generating an input/output (I/O) request to the hardware device;

responsive to determining that a machine address corresponding to the guest physical address is missing, setting up a mapping from the guest physical address to the machine address using an interrupt of an I/O MMU unit (input/output memory management unit); and

performing a DMA operation with the machine address.

7. The method of claim 1, further comprising:

the guest operating system generating an input/output (I/O) request to the hardware device with a guest physical address that is identical to a corresponding machine address; and

performing a DMA operation using the guest physical address.

8. For a virtualized computer system in which a guest operating system runs on a virtual machine of the virtualized computer system, a computer program product stored on a computer readable medium and including computer instructions configured to perform a method of providing the guest operating system with direct access to a hardware device coupled to the virtualized computer system via a communication interface, the method comprising:

obtaining first configuration register information corresponding to the hardware device, the hardware device connected to the virtualized computer system via the communication interface;

creating a passthrough device by copying at least part of the first configuration register information to generate second configuration register information corresponding to the passthrough device; and

enabling the guest operating system to directly access the hardware device corresponding to the passthrough device by providing access to the second configuration register information of the passthrough device.

9. The computer program product of claim 8, wherein the method further comprises:

receiving an input/output (I/O) request from the guest operating system with a first guest physical address corresponding to the passthrough device;

mapping the first guest physical address to a first machine address corresponding to the hardware device;

performing an I/O operation with the first machine address; and

allowing the guest operating system to perform a subsequent I/O operation with a second guest physical address directly without mapping the second guest physical address to a second machine address.

10. The computer program product of claim 8, wherein the method further comprises:

receiving an input/output (I/O) request from the guest operating system with a first guest physical address corresponding to the passthrough device; and

performing a proxy I/O operation with a first machine address corresponding to the first guest physical address.

11. The computer program product of claim 8, wherein the method further comprises:

receiving an input/output (I/O) request from the guest operating system with a guest physical address corresponding to the passthrough device;

mapping the guest physical address to a machine address; and

performing a DMA operation with the machine address.

12. The computer program product of claim 8, wherein the method further comprises:

receiving an input/output (I/O) request from the guest operating system with a guest physical address corresponding to the passthrough device;

mapping the guest physical address to a machine address and providing the machine address to the guest operation system, and

the guest operating system generating the I/O request directly to the hardware device with the guest physical address replaced by the machine address.

13. The computer program product of claim 8, wherein the method further comprises:

the guest operating system generating an input/output (I/O) request to the hardware device;

responsive to determining that a machine address corresponding to the guest physical address is missing, setting up a mapping from the guest physical address to the machine address using an interrupt of an I/O MMU unit (input/output memory management unit); and

performing a DMA operation with the machine address.

14. The computer program product of claim 8, wherein the method further comprises:

the guest operating system generating an input/output (I/O) request to the hardware device with a guest physical address that is identical to a corresponding machine address; and

performing a DMA operation using the guest physical address.

15. A virtualized computer system in which a guest operating system runs on a virtual machine of the virtualized computer system, the virtualized computer system including a storage device storing computer instructions configured to perform a computer-implemented method of providing the guest operating system with direct access to a hardware device coupled to the virtualized computer system via a communication interface, and one or more central processing units for executing the computer instructions, the method comprising:

obtaining first configuration register information corresponding to the hardware device, the hardware device connected to the virtualized computer system via the communication interface;

creating a passthrough device by copying at least part of the first configuration register information to generate second configuration register information corresponding to the passthrough device; and

enabling the guest operating system to directly access the hardware device corresponding to the passthrough device by providing access to the second configuration register information of the passthrough device.

16. The virtualized computer system of claim 15, wherein the method further comprises:

receiving an input/output (I/O) request from the guest operating system with a first guest physical address corresponding to the passthrough device;

mapping the first guest physical address to a first machine address corresponding to the hardware device;

performing an I/O operation with the first machine address; and

allowing the guest operating system to perform a subsequent I/O operation with a second guest physical address directly without mapping the second guest physical address to a second machine address.

17. The virtualized computer system of claim 15, wherein the method further comprises:

receiving an input/output (I/O) request from the guest operating system with a first guest physical address corresponding to the passthrough device; and

performing a proxy I/O operation with a first machine address corresponding to the first guest physical address.

18. The virtualized computer system of claim 15, wherein the method further comprises:

receiving an input/output (I/O) request from the guest operating system with a guest physical address corresponding to the passthrough device;

mapping the guest physical address to a machine address; and

performing DMA operation with the machine address.

19. The virtualized computer system of claim 15, wherein the method further comprises:

receiving an input/output (I/O) request from the guest operating system with a guest physical address corresponding to the passthrough device;

mapping the guest physical address to a machine address and providing the machine address to the guest operation system, and

the guest operating system generating the I/O request directly to the hardware device with the guest physical address replaced by the machine address.

20. The virtualized computer system of claim 15, wherein the method further comprises:

the guest operating system generating an input/output (I/O) request to the hardware device;

responsive to determining that a machine address corresponding to the guest physical address is missing, setting up a mapping from the guest physical address to the machine address using an interrupt of an I/O MMU unit (input/output memory management unit); and

performing DMA operation with the machine address.

21. The virtualized computer system of claim 15, wherein the method further comprises:

the guest operating system generating an input/output (I/O) request to the hardware device with a guest physical address that is identical to a corresponding machine address; and

performing DMA operation using the guest physical address.