Managing storage protection faults

Patent metadata

Field	Value
Publication number	US-9542260-B2
Application number	US-201514840565-A
Country	US
Kind code	B2
Filing date	Aug 31, 2015
Priority date	Feb 25, 2008
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

Management of storage used by pageable guests of a computing environment is facilitated. A query instruction is provided that details information regarding the storage location indicated in the query. It specifies whether the storage location, if protected, is protected by host-level protection or guest-level protection.

First claim

What is claimed is:

1. A computer program product for facilitating management of storage of a computing environment, the computer program product comprising:
a non-transitory computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising:
attempting access to a storage location, the storage location being protected by at least one type of storage protection of one or more types of storage protection, the one or more types of storage protection including at least one of key controlled protection, access list controlled protection, dynamic address translation protection, page protection, or low address protection;
detecting, based on the attempting access to the storage location, that the attempted access of the storage location failed due to a fault of a storage protection of the at least one type of storage protection protecting the storage location, wherein the storage protection is a host level of protection or a guest level of protection;
determining, based on one or more checks, whether the detected failure of the attempted access is due to the host level of protection or the guest level of protection; and
performing an action based on the determining, wherein the action performed is one action based on the detected failure of the attempted access being due to the guest level of protection and is another action based on the detected failure of the attempted access being due to the host level of protection.

2. The computer program product of claim 1 , wherein the method further comprises obtaining information relating to the detected failure of the attempted access, the information comprising a host address or a guest address depending on whether the determining indicates the detected failure of the attempted access is due to the host level of protection or the guest level of protection, respectively.

3. The computer program product of claim 1 , wherein the attempting access comprises issuing by a pageable guest of the computing environment an instruction that attempts to perform a store into the storage location.

4. The computer program product of claim 1 , wherein the method further comprises:
performing a guest interrupt, based on the determining indicating that the detected failure of the attempted access is due to the guest level of protection; and
performing a host interrupt, based on the determining indicating that the detected failure of the attempted access is not due to the guest level of protection.

5. The computer program product of claim 1 , wherein the guest level of protection is guest dynamic address translation (DAT) protection, and the host level of protection is host DAT protection.

6. The computer program product of claim 1 , wherein the one action comprises indicating storing is not permitted by the guest level of protection.

7. The computer program product of claim 1 , wherein the storage location is at least part of an area of storage that specifies a first frame of host main storage, and wherein the other action comprises:
based on determining that the area of storage is part of a host copy-on-write scheme, assigning a second frame to the area of storage, copying contents of the first frame to the second frame, and permitting guest storing to the area of storage comprising the second frame; and
based on determining that the area of storage is not part of the host copy-on-write scheme, indicating storing is not permitted by the host level of protection.

8. The computer program product of claim 1 , wherein the failure of the attempted access is detected during execution of a pageable guest of the computing environment attempting access to the storage location.

9. The computer program product of claim 8 , wherein the pageable guest is of one architecture and is executed by a host of another architecture different from the one architecture.

10. A computer system for facilitating management of storage of a computing environment, the computer system comprising:
a memory; and
a processor in communication with the memory, wherein the computer system is configured to perform a method, said method comprising:
attempting access to a storage location, the storage location being protected by at least one type of storage protection of one or more types of storage protection, the one or more types of storage protection including at least one of key controlled protection, access list controlled protection, dynamic address translation protection, page protection, or low address protection;
detecting, based on the attempting access to the storage location, that the attempted access of the storage location failed due to a fault of a storage protection of the at least one type of storage protection protecting the storage location, wherein the storage protection is a host level of protection or a guest level of protection;
determining, based on one or more checks, whether the detected failure of the attempted access is due to the host level of protection or the guest level of protection; and
performing an action based on the determining, wherein the action performed is one action based on the detected failure of the attempted access being due to the guest level of protection and is another action based on the detected failure of the attempted access being due to the host level of protection.

11. The computer system of claim 10 , wherein the failure of the attempted access is detected during execution of a pageable guest of the computing environment attempting access to the storage location.

12. The computer system of claim 10 , wherein the method further comprises obtaining information relating to the detected failure of the attempted access, the information comprising a host address or a guest address depending on whether the determining indicates the detected failure of the attempted access is due to the host level of protection or the guest level of protection, respectively.

13. The computer system of claim 10 , wherein the method further comprises:
performing a guest interrupt, based on the determining indicating that the detected failure of the attempted access is due to the guest level of protection; and
performing a host interrupt, based on the determining indicating that the detected failure of the attempted access is not due to the guest level of protection.

14. The computer system of claim 10 , wherein the one action comprises indicating storing is not permitted by the guest level of protection.

15. The computer system of claim 10 , wherein the storage location is at least part of an area of storage that specifies a first frame of host main storage, and wherein the other action comprises:
based on determining that the area of storage is part of a host copy-on-write scheme, assigning a second frame to the area of storage, copying contents of the first frame to the second frame, and permitting guest storing to the area of storage comprising the second frame; and
based on determining that the area of storage is not part of the host copy-on-write scheme, indicating storing is not permitted by the host level of protection.

16. A computer-implemented method of facilitating management of storage of a computing environment, the computer-implemented method comprising:
attempting, by a processor, access to a storage location, the storage location being protected by at least one type of storage protection of one or more types of storage protection, the one or more types of storage protection including at least one of key controlled protection, access list controlled protectio

Assignees

• IBM

Inventors

• Farrell Mark S
• Heller Lisa Cranton
• Osisek Damian L
• Szwed Peter K

Classifications

• G06F2212/151

  Emulated environment, e.g. virtual machine · CPC title

• G06F12/1458

  by checking the subject access rights · CPC title

• G06F11/0727

  in a storage system, e.g. in a DASD or network based storage system (drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097) · CPC title

• G06F12/145

  the protection being virtual, e.g. for virtual blocks or segments before a translation mechanism · CPC title

• G06F11/073

  in a memory management context, e.g. virtual memory or cache management (memory management G06F12/00; testing of static memory units G11C29/00) · CPC title