Forced detaching of applications from DMA-capable PCI mapped devices

Patent metadata

Field	Value
Publication number	US-11243899-B2
Application number	US-201715581430-A
Country	US
Kind code	B2
Filing date	Apr 28, 2017
Priority date	Apr 28, 2017
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

A mechanism is provided in a data processing system comprising at least one processor and at least one memory, the at least one memory comprising instructions that are executed by the at least one processor and configure the at least one processor to implement a device context device driver for forced detaching of an application from mapped devices. The device context device driver receives a command to detach an application, wherein the command specifies a process descriptor associated with the application. The device context device driver identifies a plurality of matching device context entries in a list of open device contexts maintained by the device context device driver that match the process descriptor. The device context device driver marks the plurality of matching device context entries as detached. The device context device driver invalidates mapped memory areas associated with the plurality of matching device context entries. The device context device driver shuts down all device contexts associated with the plurality of matching device context entries.

First claim

What is claimed is:

1. A method, in a data processing system comprising at least one processor and at least one memory, the at least one memory comprising instructions that are executed by the at least one processor and configure the at least one processor to implement a device context device driver for forced detaching of a failed application from mapped devices, the method comprising:
receiving, by the device context device driver, a command from a detach application to detach a failed application, wherein the command specifies a process descriptor associated with the failed application, wherein the device context device driver implements memory mapping requests and maintains a list of all opened device contexts;
identifying, by the device context device driver, a plurality of matching device context entries in a list of open device contexts maintained by the device context device driver that match the process descriptor;
marking, by the device context device driver, the plurality of matching device context entries as detached;
invalidating, by the device context device driver, mapped memory areas associated with the plurality of matching device context entries; and
shutting down, by the device context device driver, all device contexts associated with the plurality of matching device context entries.

2. The method of claim 1 , wherein marking the plurality of matching device context entries as detached comprises for each given entry in the plurality of matching device context entries:
removing the given entry from the list of open device contexts;
adding the given entry to a list of device contexts to shut down; and
updating a detached state field of the given entry in the list of device contexts to shut down.

3. The method of claim 2 , wherein marking the plurality of matching device context entries as detached comprises:
taking a lock on the list of open device contexts; and
responsive to removing the plurality of matching device context entries from the list of open device contexts, releasing the lock.

4. The method of claim 2 , wherein invalidating mapped memory areas associated with the plurality of matching device context entries comprises for each given entry in the list of device contexts to shut down, invalidating mapped memory areas associated with the given entry.

5. The method of claim 2 , wherein shutting down all device contexts associated with the plurality of matching device context entries comprises shutting down all device contexts in the list of device contexts to shut down.

6. The method of claim 1 , wherein each entry of the list of open device contexts comprises an identifier of the device context, a detached state field, a process context descriptor, and a list of memory mapped areas.

7. The method of claim 6 , wherein each entry of the list of memory mapped areas comprises a start address and a length.

8. The method of claim 1 , wherein shutting down all device contexts associated with the plurality of matching device context entries comprises shutting down all device contexts associated with the plurality of matching device context entries in parallel using device command parallelism or work queues.

9. The method of claim 1 , wherein the command is provided by a detach process application programming interface in the device context device driver.

10. The method of claim 1 , further comprising:
responsive to receiving a subsequent command to add or remove a memory mapped area to a given device context, checking, by the device context device driver, a detach state of the given device context; and
responsive to detach state of the given device context being detached, returning an error.

11. A computer program product comprising a computer readable storage medium having a computer readable program stored therein, wherein the computer readable program, when executed on a computing device, causes the computing device to implement a device context device driver for forced detaching of a failed application from mapped devices, wherein the computer readable program causes the computing device to:
receive, by the device context device driver, a command from a detach application to detach a failed application, wherein the command specifies a process descriptor associated with the failed application, wherein the device context device driver implements memory mapping requests and maintains a list of all opened device contexts;
identify, by the device context device driver, a plurality of matching device context entries in a list of open device contexts maintained by the device context device driver that match the process descriptor;
mark, by the device context device driver, the plurality of matching device context entries as detached;
invalidate, by the device context device driver, mapped memory areas associated with the plurality of matching device context entries; and
shut down, by the device context device driver, all device contexts associated with the plurality of matching device context entries.

12. The computer program product of claim 11 , wherein marking the plurality of matching device context entries as detached comprises for each given entry in the plurality of matching device context entries:
removing the given entry from the list of open device contexts;
adding the given entry to a list of device contexts to shut down; and
updating a detached state field of the given entry in the list of device contexts to shut down.

13. The computer program product of claim 12 , wherein marking the plurality of matching device context entries as detached comprises:
taking a lock on the list of open device contexts; and
responsive to removing the plurality of matching device context entries from the list of open device contexts, releasing the lock.

14. The computer program product of claim 12 , wherein invalidating mapped memory areas associated with the plurality of matching device context entries comprises for each given entry in the list of device contexts to shut down, invalidating mapped memory areas associated with the given entry.

15. The computer program product of claim 12 , wherein shutting down all device contexts associated with the plurality of matching device context entries comprises shutting down all device contexts in the list of device contexts to shut down.

16. The computer program product of claim 11 , wherein each entry of the list of open device contexts comprises an identifier of the device context, a detached state field, a process context descriptor, and a list of memory mapped areas.

17. The computer program product of claim 16 , wherein each entry of the list of memory mapped areas comprises a start address and a length.

18. The computer program product of claim 11 , wherein shutting down all device contexts associated with the plurality of matching device context entries comprises shutting down all device contexts associated with the plurality of matching device context entries in parallel using device command parallelism or work queues.

19. The computer program product of claim 11 , wherein the command is provided by a detach process application programming interface in the device context device driver.

20. An apparatus comprising:
at least one processor; and
a memory coupled to the at least one processor, wherein the memory comprises instructions which, when executed by the at least one processor, cause the at least one processor to implement a device context device driver for forced detaching of a failed application from mapped devices, wherein the

Assignees

• IBM

Inventors

• Chen Lior
• Gavrilov Constantine
• SNAST Alexander

Classifications

• G06F9/4411 Primary

  Configuring for operating with peripheral devices; Loading of device drivers · CPC title

• G06F12/0891

  using clearing, invalidating or resetting means · CPC title

• G06F12/0871

  Allocation or management of cache space · CPC title

• G06F2212/286

  Mirrored cache memory · CPC title

• G06F2212/206

  Memory mapped I/O · CPC title