Undefeatable transformation for virtual machine I/O operations

• US 7,260,820 B1
• Filed: 04/26/2001
• Issued: 08/21/2007
• Est. Priority Date: 04/26/2001
• Status: Expired due to Term

• Current Assignee: VMware, Inc. (Broadcom, Inc.)
• Original Assignee: VMware, Inc. (Broadcom, Inc.)
• Inventors: Waldspurger, Carl A., Bugnion, Edouard
• Primary Examiner(s): An; Meng-Al T.
• Assistant Examiner(s): To; Jennifer N.
• Application Number:
  US09/844,581
• Time in Patent Office: 2,308 Days
• Field of Search: 718 1-108, 709200-203, 707/1, 707/200, 713187-189, 711/6
• US Class Current: 718/1
• 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
• CPC Class Codes: G06F 9/545 where tasks reside in different layers, e.g. user- and kernel-space

Abstract

I/O operations between a virtual machine (VM) and a device external to the VM are monitored by a virtual machine monitor (VMM). Data passing between the VM and the external device is transformed by the VMM, in some cases only when a predetermined filtering or triggering condition is met. Because the VMM, and thus the transformation operation, is transparent to the VM, the transformation cannot be prevented or undone or even affected by any action by a user of the VM. Examples of the non-defeatable transformation of I/O data include generating display overlays such as banners, masking out portions of a display, encryption, compression and network shaping such as bandwidth limiting.

Claims

1. A method for controlling input/output (I/O) operations of a user'"'"'s computer comprising the following steps:

implementing the user'"'"'s computer as a virtual machine (VM);

including an interface software component between the VM and a physical computer system that includes at least one device;

in the interface software component;

sensing a request for an I/O operation between the VM and the device;

performing a transformation of I/O data passing between the VM and the device, said transformation changing contents of the I/O data and being adjunct to necessary completion of the request, as issued, for the I/O operation;

the transformation of the I/O data thereby being undefeatable by any user action via the VM.

2. A method as in claim 1, in which:

the device is a display;

the I/O data is VM display data output from the VM and intended for display; and

the transformation is a replacement of at least a portion of the VM display data with non-defeatable display data stored external to the VM;

further including the step of displaying the VM display data with the non-defeatable display data overlaid.

3. A method as in claim 1, further including the following steps:

filtering the I/O data with respect to at least one predetermined filtering condition; and

performing the transformation of the I/O data only when the filtering condition is met.

4. A method as in claim 3, in which the filtering condition is that the I/O data includes at least one restricted term.

5. A method as in claim 3, in which the filtering condition is that the I/O data is from a restricted source.

6. A method as in claim 3, in which:

the I/O data includes image data;

the step of filtering the I/O data comprises detecting the presence of a representation of a target image within the image data; and

the transformation is substitution of a representation of a replacement image in place of the representation of the target image.

7. A method as in claim 6, in which:

the I/O data is in a non-character image format;

the target image is a representation of a restricted character string; and

the step of filtering the I/O data comprises applying character recognition to the I/O data.

8. A method as in claim 3, in which the filtering condition is the presence in the I/O data of a copy protection indication.

9. A method as in claim 1, in which the transformation comprises insertion into the I/O data of a source indication associated with the VM.

10. A method as in claim 1, in which the transformation is time-varying.

11. A method as in claim 1, in which the device is a network connection device.

12. A method as in claim 11, in which the transformation is a bandwidth limiting of the I/O data being transferred between the VM and the network connection device.

13. A method as in claim 11, in which:

the requested I/O operation is a transfer of the I/O data between the VM and the network connection device; and

the transformation is a time delay of the transfer.

14. A method as in claim 11, in which:

the requested I/O operation is a transfer of the I/O data from the VM to a first destination address via the network connection device;

the transformation is a redirection of the I/O data to a second destination address different from the first.

15. A method as in claim 1, in which:

the device is a display;

the display renders data stored in a display map; and

the step of performing the transformation comprises altering a selected portion of the display map.

16. A method as in claim 15, in which the step of altering the selected portion of the display data comprises substituting non-defeatable display data for the selected portion.

17. A method as in claim 15, in which the step of altering the selected portion of the display data comprises changing all occurrences in the display map of a display color to a replacement color.

18. A method as in claim 1, in which:

the device is a data storage device;

the requested I/O operation is a transfer of data between the VM and the storage device; and

the step of performing the transformation comprises changing at least a portion of the data during the transfer between the VM and the storage device.

19. A method as in claim 18, in which the step of performing the transformation of the I/O data comprises encrypting data written by the VM to the data storage device and decrypting data read from the data storage device by the VM.

20. A method as in claim 18, in which the step of performing the transformation of the I/O data comprises compressing data written by the VM to the data storage device and decompressing data read from the data storage device by the VM.

21. A method as in claim 1, in which:

the device is a network connection device;

the requested I/O operation is a transfer of data between the VM and the network connection device; and

the step of performing the transformation comprises changing at least a portion of the data during the transfer between the VM and the network connection device.

22. A method as in claim 21, in which the step of performing the transformation of the I/O data comprises encrypting data written by the VM to the network connection device and decrypting data read from the network connection device by the VM.

23. A method as in claim 21, in which the step of performing the transformation of the I/O data comprises compressing data written by the VM to the network connection device and decompressing data read from the network connection device by the VM.

24. A method as in claim 1, in which the step of performing the transformation of the I/O data comprises cryptographic transformation of the I/O data.

25. A method as in claim 3, in which:

the VM supports a plurality of I/O modes;

the step of filtering is performed on I/O data corresponding to a first one of the plurality of I/O modes; and

the predetermined transformation is applied to I/O data in a second one of the I/O modes when the I/O data in the first I/O mode satisfies a transformation-triggering criterion.

26. A method as in claim 25, in which the I/O modes include a video mode and an audio mode.

27. A method for controlling input/output (I/O) of a user'"'"'s computer comprising the following steps:

implementing the user'"'"'s computer as a virtual machine (VM);

including an interface software component between the VM and a physical computer system that includes at least one device that carries out an I/O operation on the basis of device control data;

storing the device control data associated with the VM in a buffer;

upon sensing a transformation command from an administrative system external to the VM, changing contents of the device control data by entering replacement data into at least a portion of the buffer, said replacement data being entered as a processing step that is adjunct to the necessary completion of the I/O operation;

the entry of the replacement data thereby being undefeatable by any action initiated via the VM.

28. A system having a processor for controlling input/output (I/O) operations of a user'"'"'s computer, comprising:

a virtual machine (VM) constituting the user'"'"'s computer;

an interface software component between the VM and a physical computer system that includes at least one device;

the interface software component including computer-executable code;

for sensing a request for an I/O operation between the VM and the device; and

for performing a transformation of I/O data passing between the VM and the device, said transformation changing contents of the I/O data and being adjunct to necessary completion of the request, as issued, for the I/O operation;

the transformation of the I/O data thereby being undefeatable by any action via the VM.

29. A system as in claim 28, in which the device is a display and the I/O data is VM display data.

30. A system as in claim 29, further comprising:

a display buffer for storing the VM display data that is output from the VM and is intended for display; and

a transformation software module comprising computer-executable code within the interface software component for replacing at least a portion of the VM display data stored in the display buffer with non-defeatable display data;

in which the display is provided for displaying the contents of the display buffer.

31. A system as in claim 28, in which the device is a data storage device.

32. A system as in claim 28, in which the device is a network connection device.