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| Prolog Control Block Contents SDNX 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.

SDNX Prolog | Top of page

     NAME       : HCPSDNX
     DESCRIPTION: State Description Annex
     DSECT      : SDNX
     FUNCTION   : Maps the State Description Annex
     LOCATED BY : SIESDNXD field in SIEBK (host real)
     CREATED BY : HCPSDN when a guest first attempts to use a
                  feature requiring an SD annex.
     DELETED BY : HCPSDN during RESET CLEAR, LOGOFF or DETACH
                  CPU processing
     REFERENCES : None
     SERIALIZED :
     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 LGRSDNX 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.
     COMPATIBILITY AND MIGRATION CONCERNS : The format of this control block is defined by the
                  z/Architecture CPU Architecture.
     GENERAL NOTES      : Although the architecture defines the minimum size
                  for an SD annex to be 64 bytes, this implementation
                  uses a minimum of 256 bytes so as to ensure cache-
                  line alignment.

SDNX Control Block Content | Top of page

     SDNX DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      SDNX           State Description Annex
          The first eight bytes of the SDNX are defined as 'Reserved
          for Program Use'. We use the first four bytes as an eye-
          catcher, and the second four bytes to hold the host logical
          address of the owning VMDBK.
    0000    0 Bitstring    8 SDNXPROG (0)   Program use area
    0000    0 Character    4 SDNXEYE        Eyecatcher: 'SDNX'
    0004    4 Address      4 SDNXVMD        HLA of owning VMDBK
    0008    8 Bitstring   56 SDNXSYSA (0)   System use area
    0008    8 Bitstring    8 *              Reserved
          Feature control blocks. Add new ones to the list as
          necessary.
    0010   16 Bitstring   32 SDNXGSCB       Guarded-Storage Control Block
          IBM Reservered Area 1
    0030   48 Bitstring   16 SDNXIBM1       Reserved for IBM use
          The next statement must appear after all of the feature
          control blocks.
              00000040       SDNXDLEN       *-SDNX Length of defined data
          The architecture requires the State Description Annex to
          have a length that is a power of two, the minimum being 64
          and the maximum 4096. We assign a minimum of 256 bytes so
          as to ensure cache-line alignment.
          These values define the control block sizes that will be
          allocated by CP.
              00000008       SDNXC          8 Characteristic: 2**8 = 256
              00000020       SDNXSIZE       32 SDNX size in doublewords
    0040   64 Bitstring    1 *              Pad to 256-byte boundary

SDNX Storage Layout | Top of page

    *** SDNX - State Description Annex
    *
    *     +---------------------------+---------------------------+
    *   0 |         SDNXEYE           |         SDNXVMD           |
    *     +---------------------------+---------------------------+
    *   8 |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    *  10 |                                                       |
    *     =                       SDNXGSCB                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  30 |                       SDNXIBM1                        |
    *     |                                                       |
    *     +------+------------------------------------------------+
    *  40 |//////|////////////////////////////////////////////////|
    *     +------+////////////////////////////////////////////////|
    *  48 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    * 100
    *
    *** SDNX - State Description Annex

SDNX Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    SDNXC          0030 00000008
    SDNXDLEN       0030 00000040
    SDNXEYE        0000
    SDNXGSCB       0010
    SDNXIBM1       0030
    SDNXPROG       0000
    SDNXSIZE       0030 00000020
    SDNXSYSA       0008
    SDNXVMD        0004

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:30:23 EDT.
Copyright IBM Corporation, 1990, 2020