Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

#### VPG64

Prolog

Control Block Contents
VPG64 DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### VPG64 Control Block Content

#### VPG64 DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      VPG64          VIRTUAL PAGE BLOCK
    0000    0 Dbl-Word     8 VPGGPAG        Page Table Entry
    0008    8 Dbl-Word     8 VPGGNEXT (0)   Address for next VPGBK
    0008    8 Dbl-Word     8 * (255)
    0800 2048 Dbl-Word     8 VPGGPGS        Page Status Table Entry
    0808 2056 Dbl-Word     8 * (255)
    1000 4096 Dbl-Word     8 VPGGASA        Auxiliary Storage Address Entry
    1008 4104 Dbl-Word     8 * (255)
         Mapping for an ESAME PAG64
    0000    0 Dbl-Word     8 VPGGPTE (0)    VPGBK Page Table Entry
    0000    0 Dbl-Word     8 VPGGPNTR       Hardware Page Table Entry
    0000    0 Signed       4 VPGGPTE0       Word 0 of ESAME PAGTE
    0004    4 Signed       4 VPGGPTE1       Word 1 of ESAME PAGTE
    0000    0 Signed       2 VPGGPLNK       This field is used to point to
                                            the next free Page Table Entry
                                            available in this PGMBK (for non-
                                            Pageable PGMBK frames only -
                                            NPGM) which were previously
                                            deallocated.
    0002    2 Signed       2 *              Reserved for IBM use
    0004    4 Signed       4 *              Reserved for IBM use
    0000    0 Signed       4 VPGGXSBN       Xstore block number if PTE is not
                                            valid and PGSXSTOR is b'1'
    0004    4 Signed       4 *              Reserved for IBM use
    0000    0 Signed       4 *              Bits 0-31 of ESAME PFRA
    0004    4 Signed       2 *              Bits 32-47 of ESAME PFRA
    0006    6 Bitstring    1 VPGGPSTA       Bits 48-51 of ESAME PFRA For a
                                            valid-in-real-storage PTE, bits
                                            52 and 55 must be zero. Bits 53
                                            and 54 are Page-invalid and
                                            Page-protection, respectively.
              1111 ....      PAGGSPFR       X'F0' Bits 48-51 of PFRA (if
                                            valid) or bits 28-31 of XSBN (if
                                            valid in xstore)
              .... 1..1      PAGGSMBZ       X'09' Must be zero in any valid
                                            PTE
              .... .1..      PAGGINVA       X'04' PTE is invalid: I-bit
              .... ..1.      PAGGPROT       X'02' Page protected (read only):
                                            P-bit
              .... .1.1      PAGGSXVA       X'05' Page is invalid, but is
                                            valid in xstore This is a
                                            non-architected . software
                                            definition.
    0007    7 Bitstring    1 *              This byte is not architected and
                                            is available for software use. It
                                            is recommended that software
                                            refrain from using this byte
                                            unless it is to store the guest
                                            storage key.
         Mapping for an ESAME PGS64
    0800 2048 Dbl-Word     8 VPGGPGST (0)   VPGBK Page Status Entry
    0800 2048 Dbl-Word     8 VPGGSNTR       Virtual Page Status Entry
    0800 2048 Signed       4 VPGGPGS0       Word 0 of ESAME PGSTE
    0804 2052 Signed       4 VPGGPGS1       Word 1 of ESAME PGSTE
    0800 2048 Bitstring    3 VPGGVRSF       Field containing VPGGSVKY,
                                            VPGGSRCP and VPGGSFLG
    0803 2051 Bitstring    1 *              Reserved for IBM use
    0800 2048 Bitstring    1 VPGGSVKY       Guest Storage Key Bits 0-4
    0801 2049 Bitstring    1 VPGGSRCP       Architected area for RCP Byte If
                                            the storage key assist is being
                                            utilized. (See the PGSTE and
                                            RCPTE Control Blocks for further
                                            details)
              1... ....      RCPLOCK        X'80' RCP LOCK HELD
              .1.. ....      RCPHREF        X'40' HOST BACKUP REFERENCE BIT
              ..1. ....      RCPHCH         X'20' HOST BACKUP CHANGE BIT
              .11. ....      RCPHOST        RCPHREF+RCPHCH MASK FOR HOST BITS
              .... .1..      RCPGREF        X'04' GUEST BACKUP REFERENCE BIT
              .... ..1.      RCPGCH         X'02' GUEST BACKUP CHANGE BIT
              .... .11.      RCPGUEST       RCPGREF+RCPGCH MASK FOR GUEST
                                            BITS
              1... ....      PGSPCL         X'80' Page Control Lock
              .1.. ....      PGSRCPHR       X'40' Host backup reference bit
                                            used for system pages
              ..1. ....      PGSRCPHC       X'20' Host backup change bit used
                                            for system pages
              .11. ....      PGSHOST        PGSRCPHR+PGSRCPHC Mask for host
                                            bits
              .... .1..      PGSGREF        X'04' Guest backup reference bit
              .... ..1.      PGSGCH         X'02' Guest backup change bit
              .... .11.      PGSGUEST       PGSGREF+PGSGCH Mask for guest
                                            bits
    0802 2050 Bitstring    1 VPGGSFLG       Virtual Page Flags
              1... ....      PGSINVAL       X'80' No auxiliary storage
                                            assigned Notes : PGSINVAL, in
                                            combination with other PTE,
                                            PGSTE, and storage key status
                                            bits, is used by steal processing
                                            to identify first time reference
                                            pages of zeros which have never
                                            been re-referenced or changed and
                                            can simply be discarded. The
                                            "first time reference page of
                                            zeros" state is identified by the
                                            following bit combination:
                                            noformat PTE: PAGINVAL=0 (page is
                                            valid and resident) PGSTE:
                                            PGSINVAL=1 (no DASD slot
                                            assigned) PGSRCPHR=0
                                            (unreferenced) PGSRCPHC=0
                                            (unchanged) Real frame storage
                                            key: Reference=0 (unreferenced)
                                            Change =0 (unchanged) enoformat
                                            Any resident page in this state
                                            is assumed to be unchanged zeros,
                                            and therefore simply discardable
                                            by steal. No page with non-zero
                                            contents should ever be allowed
                                            to be in this state, or a lost
                                            page will eventually result. The
                                            host change bit, PGSRCPHC, should
                                            be used to indicate that a page
                                            which is unchanged, not already
                                            on DASD, and non-zero, must be
                                            eventually written to DASD. *
                                            Note that both reference bits
                                            (PGSRCPHR and the real storage
                                            frame reference bit) can
                                            "evaporate" to zero over time due
                                            to the action of the reorder
                                            function. Therefore, the fact
                                            that a frame has been referenced,
                                            or setting PGSRCPHR on, can not
                                            prevent a page from eventually
                                            entering this "first time
                                            reference page of zeros" state.
              .1.. ....      PGSSHARE       X'40' Page is a shared page
              ..1. ....      PGS1READ       X'20' ASA may be read only once.
                                            Used for shared pages. After the
                                            first read, this SDF (System Data
                                            File) ASA is to be ignored and
                                            the page left as changed. When
                                            the page is first written, it
                                            will go to a paging space ASA and
                                            this flag wil be turned off.
                                            PGS1READ on implies that page is
                                            read-only for the user.
              ...1 ....      PGSALLOC       X'10' Page in the system address
                                            space (or a system-owned utility
                                            address space) that is allocated,
                                            OR A shared CP page in the
                                            monitor DCSS that CP has
                                            translated and that has not yet
                                            been released by the user
                                            connected to the DCSS. When this
                                            bit is on: 1) The page is never
                                            part of a DASD block; 2) The
                                            associated PGMBK is never paged
                                            out.
              .... 1...      PGSFIXED       X'08' Storage slot permanently
                                            assigned
              .... .1..      PGSIO1ST       X'04' Indicate the first page of
                                            PGMBK has completed I/O.
                                            Serialized via PGSTRANS.
              .... ..1.      PGSIO2ND       X'02' Indicate the second page of
                                            PGMBK has completed I/O.
                                            Serialized via PGSTRANS.
              .... .11.      PGSIOFLG       PGSIO1ST+PGSIO2ND
    0803 2051 Bitstring    1 VPGGSSTA       Virtual Page Status bits
    0803 2051 Bitstring    1 VPGGMSTA       Virtual Page (PGMBK) Status bits
    0804 2052 Signed       4 VPGGAUX        Time this page was written
         Mapping for an ESAME ASA64
    1000 4096 Dbl-Word     8 VPGGASAT (0)   VPGBK Aux Storage Address
    1000 4096 Dbl-Word     8 VPGGANTR       Auxiliary Storage Address
    1000 4096 Signed       4 VPGGASA0       Word 0 of ESAME ASATE
    1004 4100 Signed       4 VPGGASA1       Word 1 of ESAME ASATE
    1000 4096 Signed       2 VPGGACNM       Auxiliary Storage Cylinder Number
    1002 4098 Bitstring    1 VPGGAPNM       Auxiliary Storage Page Number
    1003 4099 Bitstring    1 VPGGAVOL       Auxiliary Storage Volume Code
    1004 4100 Signed       4 VPGGPTRM       PTRM-specific data. Only valid in
                                            PTRM non-pageable PGM64s If
                                            PGSINVAL=b'0', then this is the
                                            ASA representing the second page
                                            of the PGM64 If PGSXSTOR=b'1',
                                            then this is the XSTORE block
                                            number representing the second
                                            page of the PGM64. .* .*

#### VPG64 Storage Layout

    *** VPG64 - VIRTUAL PAGE BLOCK
    *
    *     +-------------------------------------------------------+
    *   0 |                       VPGGPAG                         |
    *     +-------------------------------------------------------+
    *   8 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    * 800 |                       VPGGPGS                         |
    *     +-------------------------------------------------------+
    * 808 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    *1000 |                       VPGGASA                         |
    *     +-------------------------------------------------------+
    *1008 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    *1800
    *
    *** VPG64 - VIRTUAL PAGE BLOCK

    *** Overlay for VPGGPAG in VPG64
    *
    *     +-------------------------------------------------------+
    *   0 |                       VPGGPNTR                        |
    *     +-------------------------------------------------------+
    *   8
    *
    *** Overlay for VPGGPAG in VPG64

    *** Overlay for VPGGPNTR in VPG64
    *
    *     +---------------------------+---------------------------+
    *   0 |         VPGGPTE0          |         VPGGPTE1          |
    *     +---------------------------+---------------------------+
    *   8
    *
    *** Overlay for VPGGPNTR in VPG64

    *** Overlay for VPGGPTE0 in VPG64
    *
    *     +-------------+-------------+---------------------------+
    *   0 |  VPGGPLNK   |/////////////|///////////////////////////|
    *     +-------------+-------------+---------------------------+
    *   8
    *
    *** Overlay for VPGGPTE0 in VPG64

    *** Overlay for VPGGPTE0 in VPG64
    *
    *     +---------------------------+---------------------------+
    *   0 |         VPGGXSBN          |///////////////////////////|
    *     +---------------------------+---------------------------+
    *   8
    *
    *** Overlay for VPGGPTE0 in VPG64

    *** Overlay for VPGGPTE0 in VPG64
    *
    *     +---------------------------+-------------+------+------+
    *   0 |///////////////////////////|/////////////|:GPSTA|//////|
    *     +---------------------------+-------------+------+------+
    *   8
    *
    *** Overlay for VPGGPTE0 in VPG64

    *** Overlay for VPGGPGS in VPG64
    *
    *     +-------------------------------------------------------+
    * 800 |                       VPGGSNTR                        |
    *     +-------------------------------------------------------+
    * 808
    *
    *** Overlay for VPGGPGS in VPG64

    *** Overlay for VPGGSNTR in VPG64
    *
    *     +---------------------------+---------------------------+
    * 800 |         VPGGPGS0          |         VPGGPGS1          |
    *     +---------------------------+---------------------------+
    * 808
    *
    *** Overlay for VPGGSNTR in VPG64

    *** Overlay for VPGGPGS0 in VPG64
    *
    *     +--------------------+------+
    * 800 |     VPGGVRSF       |//////| 804
    *     +--------------------+------+
    *
    *** Overlay for VPGGPGS0 in VPG64

    *** Overlay for VPGGPGS0 in VPG64
    *
    *     +------+------+------+------+
    * 800 |:GSVKY|:GSRCP|:GSFLG|:GSSTA| 804
    *     +------+------+------+------+
    *
    *** Overlay for VPGGPGS0 in VPG64

    *** Overlay for VPGGSSTA in VPG64
    *
    *                          +------+
    * 800 ...              803 |:GMSTA| 804
    *                          +------+
    *
    *** Overlay for VPGGSSTA in VPG64

    *** Overlay for VPGGPGS1 in VPG64
    *
    *                                 +---------------------------+
    * 800 ...                     804 |         VPGGAUX           |
    *                                 +---------------------------+
    * 808
    *
    *** Overlay for VPGGPGS1 in VPG64

    *** Overlay for VPGGASA in VPG64
    *
    *     +-------------------------------------------------------+
    *1000 |                       VPGGANTR                        |
    *     +-------------------------------------------------------+
    *1008
    *
    *** Overlay for VPGGASA in VPG64

    *** Overlay for VPGGANTR in VPG64
    *
    *     +---------------------------+---------------------------+
    *1000 |         VPGGASA0          |         VPGGASA1          |
    *     +---------------------------+---------------------------+
    *1008
    *
    *** Overlay for VPGGANTR in VPG64

    *** Overlay for VPGGASA0 in VPG64
    *
    *     +-------------+------+------+
    *1000 |  VPGGACNM   |:GAPNM|:GAVOL| 1004
    *     +-------------+------+------+
    *
    *** Overlay for VPGGASA0 in VPG64

    *** Overlay for VPGGASA1 in VPG64
    *
    *                                 +---------------------------+
    *1000 ...                    1004 |         VPGGPTRM          |
    *                                 +---------------------------+
    *1008
    *
    *** Overlay for VPGGASA1 in VPG64

#### VPG64 Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    PAGGINVA       0006 04
    PAGGPROT       0006 02
    PAGGSMBZ       0006 09
    PAGGSPFR       0006 F0
    PAGGSXVA       0006 05
    PGSALLOC       0802 10
    PGSFIXED       0802 08
    PGSGCH         0801 02
    PGSGREF        0801 04
    PGSGUEST       0801 06
    PGSHOST        0801 60
    PGSINVAL       0802 80
    PGSIOFLG       0802 06
    PGSIO1ST       0802 04
    PGSIO2ND       0802 02
    PGSPCL         0801 80
    PGSRCPHC       0801 20
    PGSRCPHR       0801 40
    PGSSHARE       0802 40
    PGS1READ       0802 20
    RCPGCH         0801 02
    RCPGREF        0801 04
    RCPGUEST       0801 06
    RCPHCH         0801 20
    RCPHOST        0801 60
    RCPHREF        0801 40
    RCPLOCK        0801 80
    VPGGACNM       1000
    VPGGANTR       1000
    VPGGAPNM       1002
    VPGGASA        1000
    VPGGASAT       1000
    VPGGASA0       1000
    VPGGASA1       1004
    VPGGAUX        0804
    VPGGAVOL       1003
    VPGGMSTA       0803
    VPGGNEXT       0008
    VPGGPAG        0000
    VPGGPGS        0800
    VPGGPGST       0800
    VPGGPGS0       0800
    VPGGPGS1       0804
    VPGGPLNK       0000
    VPGGPNTR       0000
    VPGGPSTA       0006
    VPGGPTE        0000
    VPGGPTE0       0000
    VPGGPTE1       0004
    VPGGPTRM       1004
    VPGGSFLG       0802
    VPGGSNTR       0800
    VPGGSRCP       0801
    VPGGSSTA       0803
    VPGGSVKY       0800
    VPGGVRSF       0800
    VPGGXSBN       0000

This information is based on z/VM V4R3.0. Last updated on 1 May 2002 at 10:59:20 EDT.
Copyright IBM Corporation, 1990, 2002