Granted Patent B2

US 8,661,436 · App. 12/967,362 · Granted Feb 25, 2014

Inventors: James McKenzie (Cambridge, GB); Jean Guyader (Cambridge, GB)

Assignee: Citrix Systems, Inc.

Abstract

Claims (43)

1. In a computing device executing a hypervisor hosting a plurality of virtual machines, a method for granting by a drive manager a virtual machine exclusive access to an optical disc drive responsive to a determination the virtual machine initiated a transaction with the optical disc drive, the drive manager hosted outside of the virtual machine, comprising:

mapping, by a drive manager executed by a processor of a computing device, an optical disc drive connected to the computing device to a plurality of virtual machines hosted by a hypervisor executed by the computing device, to allow the plurality of virtual machines to initiate transactions with the optical disc drive;

intercepting, by the drive manager, a transaction stream generated by the optical disc drive comprising machine commands of the optical disc drive;

converting, by the drive manager, the transaction stream to a command stream that can be processed by an operating system;

determining, by the drive manager based on an analysis of the command stream, a first virtual machine of the plurality of virtual machines initiated a transaction with the optical disc drive;

locking, by the drive manager responsive to the determination, the optical disc drive from one or more additional transactions initiated from the plurality of virtual machines, to grant the first virtual machine exclusive access to the optical disc drive during the transaction with the first virtual machine;

determining, by the drive manager subsequent to locking the optical disc drive, the first virtual machine stopped transacting with the optical disc drive; and

unlocking, by the drive manager, the optical disc drive.

2. The method of claim 1 , further comprising:

determining, by the drive manager, a second virtual machine of the plurality of virtual machines initiated a transaction with the optical disc drive; and

locking, by the drive manager, the optical disc drive to grant the second virtual machine exclusive access to the optical disc drive.

3. The method of claim 1 , wherein mapping the optical disc drive to a plurality of virtual machines comprises updating each of the plurality of virtual machines' virtualized views of available physical resources to simultaneously include the optical disc drive.

4. The method of claim 1 , wherein locking the optical disc drive further comprises preventing, while the first virtual machine accesses the optical disc drive, a second virtual machine of the plurality of virtual machines from transacting with the optical disc drive.

5. The method of claim 1 , wherein intercepting a transaction stream further comprises intercepting a transaction stream comprising small computer system interface (SCSI) commands.

6. The method of claim 1 , wherein determining the first virtual machine initiated a transaction further comprises determining the first virtual machine began writing to a disc in the optical disc drive.

7. The method of claim 1 , wherein determining the first virtual machine initiated a transaction further comprises determining the virtual machine began reading from a disc in the optical disc drive.

8. The method of claim 1 , further comprising:

intercepting, by the drive manager, a request for access to the optical disc drive generated by a second virtual machine of the plurality of virtual machines; and

queuing the request, by the drive manager, while the optical disc drive is locked.

9. The method of claim 1 , further comprising:

intercepting, by the drive manager, a command generated by the first virtual machine and transmitted to the optical disc drive;

determining, by the drive manager and responsive to a permission policy applied to credentials of the first virtual machine, that the first virtual machine lacks permission to issue the command to the optical disc drive; and

preventing, by the drive manager, the optical disc drive from receiving the command.

10. In a computing device executing a hypervisor hosting a plurality of virtual machines, a system for granting by a drive manager a virtual machine exclusive access to an optical disc drive responsive to a determination the virtual machine initiated a transaction with the optical disc drive, the drive manager hosted outside of the virtual machine, comprising:

an optical disc drive;

a computing device, connected to the optical disc drive, comprising a processor executing a drive manager and a hypervisor hosting a plurality of virtual machines; and

wherein the drive manager is configured to:

map the optical disc drive to the plurality of virtual machines, to allow the plurality of virtual machines to initiate transactions with the optical disc drive,

intercept a transaction stream generated by the optical disc drive comprising machine commands of the optical disc drive,

convert the transaction stream to a command stream that can be processed by an operating system,

determine, based on an analysis of the command stream, a first virtual machine of the plurality of virtual machines initiated a transaction with the optical disc drive, and

lock, responsive to the determination, the optical disc drive from one or more additional transactions initiated from the plurality of virtual machines, to grant the first virtual machine exclusive access to the optical disc drive during the transaction with the first virtual machine, wherein the drive manager determines, subsequent to locking the optical disc drive, that the first virtual machine stopped transacting with the optical disc drive, and unlocks the optical disc drive.

11. The system of claim 10 , wherein the drive manager is further configured to determine a second virtual machine of the plurality of virtual machines initiated a transaction with the optical disc drive; and lock the optical disc drive to grant the second virtual machine exclusive access to the optical disc drive.

12. The system of claim 10 , wherein the drive manager is further configured to update each of the plurality of virtual machines' virtualized views of available physical resources to simultaneously include the optical disc drive.

13. The system of claim 10 , wherein the drive manager is further configured to prevent, while the first virtual machine accesses the optical disc drive, a second virtual machine of the plurality of virtual machines from transacting with the optical disc drive.

14. The system of claim 10 , wherein the drive manager is further configured to intercept a transaction stream comprising small computer system interface (SCSI) commands.

15. The system of claim 10 , wherein the drive manager is further configured to determine the first virtual machine began writing to a disc in the optical disc drive.

16. The system of claim 10 , wherein the drive manager is further configured to determine the virtual machine began reading from a disc in the optical disc drive.

17. The system of claim 10 , wherein the drive manager is further configured to intercept a request for access to the optical disc drive generated by a second virtual machine of the plurality of virtual machines; and queue the request while the optical disc drive is locked.

18. The system of claim 10 , wherein the drive manager is further configured to:

intercept a command generated by the first virtual machine and transmitted to the optical disc drive;

determine, responsive to a permission policy applied to credentials of the first virtual machine, that the first virtual machine lacks permission to issue the command to the optical disc drive; and

prevent the optical disc drive from receiving the command.

Assignments (9)

Continuity (8)