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Prolog 
Control Block Contents 
   SPIBK 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.


  SPIBK Prolog Top of page
 
 NAME       : HCPSPIBK
 DESCRIPTION: Space Permission Information BlocK
 DSECT      : SPIBK
 FUNCTION   : Defines one address space's permission to
              attach another address space to its access
              list.
 LOCATED BY : ASCSPIBK  Pointer to chain of SPIBKs designating
              which users are permitted to attach this
              space to their guest-use access list.
              ALCSPIBK  Anchor for chain of SPIBKs defining
              which address spaces may be attached to
              this guest-use access list.
 CREATED BY : HCPSPM - When the first permission for an access
              list to access an address space is granted.
 DELETED BY : HCPSPM - When the last permission for an access
              list to access an address space is revoked.
 SERIALIZED : All fields in this control block, as well
              as the ASCSPIBK and ALCSPIBK fields in
              the ASCBK and the ALCBK are serialized
              by the Space-Permission-Manager lock,
              RSASPMLK in HCPRSM.
 RELOCATION CONSIDERATIONS : None
 COMMENTS   : The allocation default for this control block
              is 'VIRTUAL'. If the default is not overridden,
              this control block comes from and is returned
              to the virtual free storage CP utility address
              space. Access register mode must be entered
              in order to use this storage. The ALET for the
              virtual free storage CP utility address space
              resides in HCPSYSCM. If the TYPE= parameter is
              overridden on the HCPGETST macro from virtual
              to some other type (all other types are real)
              or vice versa, the HCPRELST TYPE= parameter
              MUST also be overridden.
              Both the address space permission chain and
              the access list permission chain are
              doubly-linked. In both cases, the forward
              pointer of the last element of the chain
              is zero. However, the backward pointer
              of the first element in the chain is also
              zero, instead of pointing back to the ASCBK
              or ALCBK anchor field. Since the ASCBKs and
              ALCBKs are in real storage, their addresses
              are real addresses and there would need to be
              some way to determine when the anchor address
              was reached in order to properly handle it.
              To avoid dealing with that problem (since it's
              not really critical that we take that last step
              backward), we simply zero the backward pointer
              of the first chain element.
 
 
  SPIBK Control Block Content Top of page
 

 SPIBK DSECT Top of page
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure SPIBK Space Permission Information BlocK 0000 0 Address 4 SPISPFOR Space forward pointer to next SPIBK in chain defining what spaces are permitted to attach this space to their guest-use access list. Chain starts in an ASCBK. 0004 4 Address 4 SPISPBAC Backward pointer to a previous SPIBK on an ASCBK's chain. 0008 8 Address 4 SPIALFOR Access List forward pointer to next SPIBK in chain defining what spaces may be attached to this guest-use access list. Chain starts in ALCBK. 000C 12 Address 4 SPIALBAC Backward pointer to previous SPIBK on an ALCBK's chain. The following two fields are static while the SPIBK is chained 0010 16 Address 4 SPIALCBK The address of the ALCBK defining the access list which is permitted to attach the address space described by SPIASCBK. 0014 20 Address 4 SPIASCBK The address of the ASCBK defining the address space which may be attached to the the access list described by SPIALCBK. 0018 24 Bitstring 1 SPIPERM Permission flags 1... .... SPMDEBUG X'80' SPMDEBUG Debug-type access is requested or permitted. .1.. .... SPMPRGRW X'40' SPMPRGRW Program-type read-write access is requested or permitted. ..1. .... SPMPRGRO X'20' SPMPRGRO Program-type read-only access is requested or permitted. ...1 .... SPMPRGRD X'10' SPMPRGRD Program-type read access is requested or permitted. Parameter input to HCPSTP. 1... .... STPDSB2G X'80' STPDSB2G Caller says STPTR can turn demand scan off for frames <2G. 0019 25 Bitstring 1 * (3) Reserved for future IBM use 001C 28 Signed 4 * Reserved for future IBM use 00000004 SPISIZE (*-SPIBK+7)/8 Length of SPIBK in DWs
 
 
  SPIBK Storage Layout Top of page
 
          
*** SPIBK - Space Permission Information BlocK
*
*     +---------------------------+---------------------------+
*   0 |         SPISPFOR          |         SPISPBAC          |
*     +---------------------------+---------------------------+
*   8 |         SPIALFOR          |         SPIALBAC          |
*     +---------------------------+---------------------------+
*  10 |         SPIALCBK          |         SPIASCBK          |
*     +------+--------------------+---------------------------+
*  18 |:PERM |////////////////////|///////////////////////////|
*     +------+--------------------+---------------------------+
*  20
*
*** SPIBK - Space Permission Information BlocK
 
 
  SPIBK Cross Reference Top of page
 
 
Symbol         Dspl Value
-------------- ---- -----
SPIALBAC       000C
SPIALCBK       0010
SPIALFOR       0008
SPIASCBK       0014
SPIPERM        0018
SPISIZE        001C 00000004
SPISPBAC       0004
SPISPFOR       0000
SPMDEBUG       0018 80
SPMPRGRD       0018 10
SPMPRGRO       0018 20
SPMPRGRW       0018 40
STPDSB2G       0018 80
 
This information is based on z/VM 7.3.0 Last updated on 22 Jun 2022 at 15:56:10 EDT.
Copyright IBM Corporation, 1990, 2022