CHCBK Back to Index page
 
Prolog 
Control Block Contents 
   CHCBK DSECT
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.


  CHCBK Prolog Top of page
 
 NAME       : HCPCHCBK
 DESCRIPTION: CHANNEL CLASS BLOCK
 DSECT      : CHCBK
 FUNCTION   : DESCRIBE THE STATUS OF THE CHANNELS ( IN XA MODE, THE
              CHANNEL CLASSES) FOR A VIRTUAL MACHINE.
              ANCHOR THE QUEUE OF DEVICES (FOR EACH CHANNEL NUMBER OR
              CLASS) FOR WHICH INTERRUPTS ARE PENDING.
 LOCATED BY : VMDCHC FIELD IN THE VIRTUAL MACHINE'S DEFINITION BLOCK
 CREATED BY : VIRTUAL MACHINE CREATION PROCESS - HCPBVM
 DELETED BY : VIRTUAL MACHINE DESTRUCTION PROCESS
 RELOCATION CONSIDERATIONS : This control block is relocated as part of a live
              guest relocation (LGR).  The bits and fields that
              need to be relocated are defined in the
              corresponding LGRCHCBK COPY file.  Whenever changes
              are made to this control block, consideration must
              be given to any effects these changes will have on
              a relocation.  If any new fields or bits are
              defined, they may need to be relocated.  If
              existing bits or fields are changed, corresponding
              modifications may be required in the LGR version of
              this control block.  Consider also the effects of
              these changes on a relocation involving a back-level
              release of CP.
 
 
  CHCBK Control Block Content Top of page
 

 CHCBK DSECT Top of page
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure CHCBK CHANNEL CLASS BLOCK 0000 0 Dbl-Word 8 CHCLOCK (0) LOCKWORD FOR THIS BLOCK 0000 0 Address 4 CHCLOWNR ADDRESS OF OWNING VMDBK 0004 4 Address 4 CHCLOCWQ QUEUE OF WAITING TASKS 0008 8 Signed 4 * Reserved for future IBM use SET-CHANNEL-MONITOR DOUBLEWORD THE FOLLOWING FIELDS CONTROL GUEST CHANNEL MONITORING. THEY ARE KEPT WITHIN A DOUBLEWORD TO ALLOW A STORE-MULTIPLE TO PERFORM MP-CONSISTENT SETTING OF THE CONTROLS ON A HOST MP. 000C 12 Signed 4 CHCKEYCN (0) Key and control word 000C 12 Bitstring 1 CHCKEY KEY OF USER MEASUREMENT BLOCK 000D 13 Bitstring 1 * RESERVED FOR FUTURE IBM USE 000E 14 Bitstring 1 * RESERVED FOR FUTURE IBM USE 000F 15 Bitstring 1 CHCHFLAG HARDWARE CONTROLS .... ..1. CHCMSM X'02' CHCMSM MEASUREMENT ACTIVE .... ...1 CHCTIM X'01' CHCTIM TIMING (SHOULD BE) ACTIVE 0010 16 Dbl-Word 8 CHCGMBO (0) zArch: 64 bit MBO for monitoring 0010 16 Signed 4 CHCGMBOH zArch: high order MBO word 0014 20 Signed 4 CHCGMBOL zArch: Low order MBO word ...1 .1.. CHCMBLKO CHCGMBOL CHCMBLKO 390: Measurement Blk Origin 0018 24 Signed 4 CHCIORW POINTER TO CHAIN OF CRWBK'S. 001C 28 Bitstring 1 CHCSFLAG SOFTWARE CONTROLS 1... .... CHCRWCC1 X'80' CHCRWCC1 CONDITION CODE 1 REMAINS TO BE GIVEN TO A GUEST STORE CHANNEL REPORT WORD SINCE GENERATING A MACHINE CHECK FOR A PREVIOUS CHANNEL REPORT WORD CONDITION. THIS BIT IS CLEARED BY AN I/O SYSTEM RESET. IT PREVENTS THE GENERATION OF A MACHINE CHECK FOR CHANNEL REPORT WORDS MADE PENDING. .1.. .... CHCEMW X'40' CHCEMW Extended-I/O-measurement-word facility has been enabled. ..1. .... CHCIPR X'20' CHCIPR Reporting of IPR CRWs in the restore-subchannel facility has been enabled. ...1 .... CHCURCHV X'10' CHCURCHV CHCURCHP is valid 001D 29 Bitstring 1 CHCURCHP CHPID for fully simulated devices - valid in base only serialized by CFM because HCPVDBCH is only called for the DEFINE command. 001E 30 Bitstring 1 * RESERVED FOR FUTURE IBM USE 001F 31 Bitstring 1 * RESERVED FOR FUTURE IBM USE 0020 32 Signed 4 CHCSALIM SET ADDRESS LIMIT VALUE DEPRECATED (no longer used) 0024 36 Signed 4 CHCMCV POINTER TO MCVBK. FOR FLOATING MACHINE CHECKS (THEY ARE RELATED TO THE I/O SUBSYSTEM). 0028 40 Dbl-Word 8 * RESERVED FOR FUTURE IBM USE 0030 48 Signed 4 * RESERVED FOR FUTURE IBM USE 0034 52 Signed 4 CHCIOPND MASK OF PENDING INTERRUPTIONS 0038 56 Dbl-Word 8 CHCQUEUE (32) FWD AND BWD INTERRUPT PTRS 00000020 CHCQSIZE (*-CHCQUEUE)/CHCQENTL DEFINE NUMBER OF CHANNELS PGID fields are only valid in CHCBK off VMDBASE This field is written once per IPL. All other references are read only. Therefore no lock is needed. 0138 312 Bitstring 1 CHCPGBY0 Non zero means CHCPGID is set 0139 313 Bitstring 11 CHCPGID Guest Path Group ID 0144 324 Bitstring 1 * (4) RESERVED CHCCHPID is only valid in the CHCBK off VMDBASE. Each byte corresponds to a virtual chpid number and contains either zero or the chpid type. A zero indicates the chpid number is available. Virtual chpids are assigned at ATTACH or DEFINE time by HCPVDBCH code. DETACH makes a virtual chpid available if possible. Chpid number FF is set to type 1A (unswitched ficon) in HCPBVM and used for all non QDIO virtual devices. The rules for QDIO devices are described in HCPVDBCH. CHCCHPID is serialized by VDEV config lock 0148 328 Bitstring 1 CHCCHPID (256) Virtual chpid table 0248 584 Dbl-Word 8 * (3) Reserved for IBM use 0260 608 Address 4 CHCPCIHQ ADDRESS OF HCPPCIHQ BLOCK 0264 612 Address 4 * RESERVED 0000004D CHCSIZE (*-CHCBK+7)/8 SIZE OF FLOATING CHANNEL BLOCK 0038 56 Signed 4 CHCQUEFW CHANNEL INT. QUEUE FORWARD PTR 003C 60 Signed 4 CHCQUEBW CHANNEL INT. QUEUE BACKWARD PTR 00000008 CHCQENTL *-CHCQUEFW LENGTH OF QUEUE POINTERS
 
 
  CHCBK Storage Layout Top of page
 
          
*** CHCBK - CHANNEL CLASS BLOCK
*
*     +---------------------------+---------------------------+
*   0 |         CHCLOWNR          |         CHCLOCWQ          |
*     +---------------------------+------+------+------+------+
*   8 |///////////////////////////|CHCKEY|//////|//////|:HFLAG|
*     +---------------------------+------+------+------+------+
*  10 |         CHCGMBOH          |         CHCGMBOL          |
*     +---------------------------+------+------+------+------+
*  18 |         CHCIORW           |:SFLAG|:URCHP|//////|//////|
*     +---------------------------+------+------+------+------+
*  20 |         CHCSALIM          |          CHCMCV           |
*     +---------------------------+---------------------------+
*  28 |///////////////////////////////////////////////////////|
*     +---------------------------+---------------------------+
*  30 |///////////////////////////|         CHCIOPND          |
*     +---------------------------+---------------------------+
*  38 |                                                       |
*     =                       CHCQUEUE                        =
*     |                                                       |
*     +------+------------------------------------------------+
* 138 |:PGBY0|                    CHCPGID                     |
*     +------+                    +---------------------------+
* 140 |                           |///////////////////////////|
*     +---------------------------+---------------------------+
* 148 |                                                       |
*     =                       CHCCHPID                        =
*     |                                                       |
*     +-------------------------------------------------------+
* 248 |///////////////////////////////////////////////////////|
*     =///////////////////////////////////////////////////////=
*     |///////////////////////////////////////////////////////|
*     +---------------------------+---------------------------+
* 260 |         CHCPCIHQ          |///////////////////////////|
*     +---------------------------+---------------------------+
* 268
*
*** CHCBK - CHANNEL CLASS BLOCK
          
*** Overlay for CHCQUEUE in CHCBK
*
*     +---------------------------+---------------------------+
*  38 |         CHCQUEFW          |         CHCQUEBW          |
*     +---------------------------+---------------------------+
*  40
*
*** Overlay for CHCQUEUE in CHCBK
 
 
  CHCBK Cross Reference Top of page
 
 
Symbol         Dspl Value
-------------- ---- -----
CHCCHPID       0148
CHCEMW         001C 40
CHCGMBO        0010
CHCGMBOH       0010
CHCGMBOL       0014
CHCHFLAG       000F
CHCIOPND       0034
CHCIORW        0018
CHCIPR         001C 20
CHCKEY         000C
CHCKEYCN       000C
CHCLOCK        0000
CHCLOCWQ       0004
CHCLOWNR       0000
CHCMBLKO       0014 14
CHCMCV         0024
CHCMSM         000F 02
CHCPCIHQ       0260
CHCPGBY0       0138
CHCPGID        0139
CHCQENTL       003C 00000008
CHCQSIZE       0038 00000020
CHCQUEBW       003C
CHCQUEFW       0038
CHCQUEUE       0038
CHCRWCC1       001C 80
CHCSALIM       0020
CHCSFLAG       001C
CHCSIZE        0264 0000004D
CHCTIM         000F 01
CHCURCHP       001D
CHCURCHV       001C 10
 
This information is based on z/VM 7.3.0 Last updated on 22 Jun 2022 at 15:48:00 EDT.
Copyright IBM Corporation, 1990, 2022