VM66800: Z/VM 7.4 CP FIX PACK - FEATURE 00 FIX 04

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• R740 Linear Service APAR
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of z/VM                            *
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  * PROBLEM DESCRIPTION:                                         *
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  This is the APAR for z/VM 7.4 Fix Pack 4.  As such it
  contains fixes for the following four problems:
  
  Problem 1
  SYSTEM HANG DUE TO MDC CONSUMING LESS THAN 2G STORAGE
  
  The system hangs. MDC is on. It may be noticed that MDC has
  nearly all of memory in use below 2G.
  
  Problem 2
  RDM024 ABEND AFTER CLEARING SSI SLOT WITH DUMMY ARD
  
  ABENDRDM024 after a Single System Image (SSI) member slot is
  made available.  Dummy ARDs are created by this process,
  either with SET SSI SLOT command or by clearing the PDF.
  The problem occurs when two dummy ARDs are compared by the
  ARD compare routine in HCPARDCA.  That comparison gives the
  result of a disjoint comparison instead of an equal comparison.
  
  Problem 3
  PEVM66675 MISSING INTERRUPT FOR DEDICATED PCI FUNCTION
  
  ISM PCI workloads involving linux guests on z/VM are
  hung/non-responsive due to a missing interrupt condition from
  the guest perspective.
  
  Problem 4
  ABENDLCK001 HCPLCK+DC8 AFTER NVME EDEV LOST
  
  ABEND LCK001 If an NVMe PCI function is configured for use with
  z/VM EDEVICE support and the PCI function is reset or removed
  from the z/VM LPAR via the Hardware Management Console.
  

Problem conclusion

• Problem 1
  SYSTEM HANG DUE TO MDC CONSUMING LESS THAN 2G STORAGE
  
  Logic was added to subroutine HCPPTG:GetFRMTEs that will
  rebalance the distribution of MDC data frames by looking at the
  current distribution and preferring frames >2G when the current
  distribution is skewed toward <2G memory.
  
  Problem 2
  RDM024 ABEND AFTER CLEARING SSI SLOT WITH DUMMY ARD
  
  The ARD comparison routine was changed to give the correct
  equality result when two dummy ARDs are compared.
  
  Problem 3
  PEVM66675 MISSING INTERRUPT FOR DEDICATED PCI FUNCTION
  
  PCI function interrupt processing code was modified to not
  alter adapter interrupt summary bits for dedicated PCI
  functions.  This will prevent missing interrupts for the
  owning guest.
  
  Problem 4
  ABENDLCK001 HCPLCK+DC8 AFTER NVME EDEV LOST
  
  An incorrect invocation of the z/VM interrupt handler for NVMe
  EDEVICES was used when the interruption presented for the PCI
  Function removal was received. This call to the NVMe interrupt
  handler has been corrected.
  

Temporary fix

Comments

• ×**** PE24/12/02 FIX IN ERROR. SEE APAR VM66815  FOR DESCRIPTION
  

APAR Information

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

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

  UM90483

Modules/Macros

• HCPARD   HCPCPE   HCPPCH   HCPPTG   7VMCPR40
  

Fix information

• Fixed component name

  VM CP CP

• Fixed component ID

  568411202

Applicable component levels

• R740 PSY UM90483

     UP24/10/14 P 2501

Fix is available

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