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 7.2.0 Last updated on 24 Jun 2020 at 09:27:16 EDT.
Copyright IBM Corporation, 1990, 2020