VM66187: ABENDASR001 DURING IPL IF LPAR HAS > 64 CPUS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• An ABENDASR001 occurs in HCPHIC when more than 64 CPUs of
  multiple CPU types are configured to a logical partition.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of z/VM running with multiple CPU      *
  *                 types who have more than 64 processors       *
  *                 configured to their logical partition.       *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  ****************************************************************
  * RECOMMENDATION: APPLY PTF                                    *
  ****************************************************************
  When more than 64 processors of multiple CPU types are
  configured to a logical partition the system could terminate
  with an ABENDASR001. The failing assertion is in HCPHIC after
  adjusting the number of remaining CPUS (TOPCPUCR) in a given
  leaf of the topology tree. If the resulting count is negative
  or greater than the z/VM supported limit on the number of
  logical processors then CP will take the subject abend.
  
  The error happens when building the data structures that
  describe the system topology because temporary storage is
  not cleared before use. The result is that several masks
  corresponding to the four polarization types (Vertical high,
  vertical medium, vertical low, and horizontal) can become
  corrupted with the residual data in the temporary storage.
  These masks, which are located in the TOPCPUPL array, must be
  mutually exclusive with each other. If they aren't, then the
  hiperdispatch routines, which determine the number of CPUs per
  type and polarization mode that are needed in the
  configuration, will incorrectly track the remaining CPUs of
  each type available in the configuration.
  
  Note that z/VM 7.1 does not currently support more than 64
  logical processors but does not inhibit a logical partition
  from having more than 64 configured. z/VM will cap the
  number of logical processors to 64 if more are configured
  to the partition.
  

Problem conclusion

• Code was added to HCPHIP where the data structures that
  describe the system topology are built, to clear the temporary
  storage location before it is loaded for use in mask
  calculations. The storage is cleared every time CP loops
  through to build the next leaf of the topology tree. This
  removes the residual data that would otherwise be compounded
  into the masks of the parents topology block. With the correct
  data the counts of CPUs tracked by hiperdispatch will be
  accurate and never go negative.
  

Temporary fix

• FOR RELEASE VM/ESACP/ESAR710 :
  PREREQ: NONE
  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:

  UM35341

Modules/Macros

• HCPHIP
  

Fix information

• Fixed component name

  VM CP

• Fixed component ID

  568411202

Applicable component levels

• R710 PSY UM35341

     UP18/07/19 P 1801

Fix is available

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