VM66871: Z/VM 7.4 CP FIX PACK - FEATURE 02 FIX 03

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• This is Feature Pack 02 Fix Pack 03 for z/VM 7.4.
  
  It contains fixes for the following problems:
  1. Coupling facility simulation fails to copy full buffer list
  2. VARY ON Hang for DASD with conflicting device IDs
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All z/VM users                               *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  ****************************************************************
  * RECOMMENDATION: APPLY PTF                                    *
  ****************************************************************
  VARY ON HANG FOR DASD WITH CONFLICTING DEVICE IDS
  --------------------------------------------------------------
  In the case where a real device is, for any particular reason,
  receiving self-description I/O across different paths which
  conflict, a VARY ONLINE command to that device could result in
  an infinite loop, warranting a re-IPL of the system.
  
  
  COUPLING FACILITY SIMULATION FAILS TO COPY FULL BUFFER LIST
  ----------------------------------------------------------------
  Coupling development found an issue with coupling instruction
  processing, which would stop short when copying buffers. It was
  found that the code was using an improper instruction to compare
  addresses, leading to buffers not being copied, breaking the
  instruction simulation.
  

Problem conclusion

• VARY ON HANG FOR DASD WITH CONFLICTING DEVICE IDS
  -------------------------------------------------------------
  A new flag and associated internal branch logic was added to
  break out of the retry loop in the case of conflicting device
  information, within the VARY ON processing of the real device
  initialization process.
  
  
  COUPLING FACILITY SIMULATION FAILS TO COPY FULL BUFFER LIST
  ------------------------------------------------------------
  A 64 bit address is initially loaded with LG, but then later
  compared using an LTR instruction. when the low word is 0,
  it assumes the entire 64 bit value is 0. The fix changed the
  LTR to LTGR and now properly compares the guest address, and
  avoids breaking coupling instruction.
  

Temporary fix

• FOR RELEASE VM/ESA CP/ESA R740 :
  PREREQ: VM66866 VM66824 VM66844
  CO-REQ: NONE
  IF-REQ: NONE
  

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UM90552

Modules/Macros

• HCPCPE   HCPMCB   HCPRDI   7VMCPR40
  

Fix information

• Fixed component name

  VM CP CP

• Fixed component ID

  568411202

Applicable component levels

• R740 PSY UM90552

     UP25/09/08 P 2502 ¢

Fix is available

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