COMBINED VIRTUAL GRAPHICS DEVICE

• US 20120266165A1
• Filed: 04/18/2011
• Published: 10/18/2012
• Est. Priority Date: 04/18/2011
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Cen, Shanwei, Cowperthwaite, David J., Srinivasan, Raman
• Granted Patent: US 8,966,477 B2
• Time in Patent Office: Days
• US Class Current: 718/1
• CPC Class Codes: G06F 9/45541 Bare-metal, i.e. hypervisor runs directly on hardware
• CPC Class Codes: G06F 9/4856 resumption being on a different machine, e.g. task migration, virtual machine migration G06F9/5088 takes precedence

Abstract

A system comprises a guest graphics subsystem with a combined virtual graphics device that combines underlying emulated virtual graphics device and virtual function of a physical graphics device to support virtual machine migration. The VMM in the system may expose to the guest a single combined virtual PCIe graphics device that combines access to the virtual graphics device and the virtual function, and switches between the virtual graphics device and the virtual function for graphics acceleration without triggering a PnP event in the guest OS. In response to the switch, the guest graphics stack and applications may redraw their windows to provide a consistent user experience.

Claims

1. A system, comprising:

a platform hardware;

a guest virtual machine; and

a virtual machine monitor to assign one of a virtual device emulated in the virtual machine monitor and a virtual function of a physical device in the platform hardware to the guest virtual machine and expose a combined virtual device to the guest virtual machine through the assigned device.

2. The system of claim 1, further comprising:

a guest driver to detect which one of the emulated virtual device and the virtual function is active for the combined virtual device and to select a plugin that matches the active device.

3. The system of claim 2, further comprising:

a virtual machine tools module to notify the guest driver of a virtual machine migration.

4. The system of claim 1, wherein the virtual machine monitor is further to expose a configuration space for the combined virtual machine to the guest virtual machine independent of the assigned device interface.

5. The system of claim 4, wherein the virtual machine monitor is further to maintain a mapping from the configuration space to the active device.

6. The system of claim 4, wherein the virtual machine monitor is further to provide one or more fields in the configuration space to cover the emulated virtual device and the virtual function.

7. The system of claim 1, wherein the emulated virtual device comprises an emulated virtual graphics device to implement emulated graphics processing capability.

8. The system of claim 2, wherein the guest driver comprises a wrapper-plugin structure, wherein the wrapper is to determine a plugin corresponding to the active device.

9. The system of claim 1, wherein the virtual machine monitor is further to switch between the emulated virtual device and the virtual function of the physical device within the combined virtual device, without triggering a plug-and-play event in a guest operating system of the guest virtual machine.

10. A method, comprising:

providing a combined virtual graphics device through one of a emulated virtual graphics device and a virtual function of a physical graphic device in a host; and

exposing the combined virtual graphics device to a guest.

11. The method of claim 10, further comprising:

switching between the emulated virtual graphics devices and a virtual function device without a hot-plug/unplug from a guest operating system of the guest.

12. The method of claim 10, further comprising:

exposing a PCIe configuration space for the combined virtual graphics device that is independent of which of the emulated virtual graphics device and the virtual function is active for the combined virtual graphics device.

13. The method of claim 12, wherein the PCIe configuration space comprises one or more fields that map to the active one of the emulated virtual graphics device and the virtual function.

14. The method of claim 10, further comprising:

in response to a switch between the emulated virtual graphics device and the virtual function, determining a plugin driver corresponding to the device that is switched to; and

initializing one of the emulated virtual graphics device and the virtual function that is switched to.

15. The method of claim 10, further comprising:

performing a switch between the the emulated virtual graphics device and the virtual function within the combined virtual device, without triggering a plug-and-play event in a guest operating system of the guest virtual machine.

16. A machine-readable medium containing instructions which, when executed by a processing system, cause the processing system to

assign one of a virtual function of a physical graphics device in a host and an emulated virtual graphics device to a guest;

and

exposing a virtual model of a PCIe graphics device to the guest, the PCIe device has graphics capability through the assigned device.

17. The machine-readable medium of claim 16, further comprising a plurality of instructions that in response to being executed result in a computing device to:

detect which one of the virtual function and the emulated virtual graphics device is active for the virtual PCIe graphics device; and

select a plugin that matches the detected active device.

18. The machine-readable medium of claim 16, further comprising a plurality of instructions that in response to being executed result in a computing device to:

expose to the guest a PCIe configuration space for the virtual PCIe graphics device, wherein the PCIe configuration space is independent of the assigned device to cover configurations of the virtual function and the emulated virtual graphics device.

19. The machine-readable medium of claim 16, further comprising a plurality of instructions that in response to being executed result in a computing device to:

in response to a virtual machine migration in the guest, perform a PCIe function level reset on the virtual PCIe graphics device to ignore access to the virtual function and the emulated virtual graphics device.

20. The machine-readable medium of claim 19, further comprising a plurality of instructions that in response to being executed result in a computing device to:

switch between the virtual function and the physical graphics device that are underlying the virtual PCIe graphics device based on the migration.