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 a PAG64 (PTE)
    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 PTE
    0004    4 Signed       4 VPGGPTE1       Word 1 of PTE
    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 Bitstring    1 VPGGXSTS (20)  Xstore time stamp (lowest 20
                                            bits)
    0018   24 Bitstring    1 * (4)          Reserved for IBM use
    001C   28 Bitstring    1 *              Reserved for IBM use
    0000    0 Signed       4 *              Bits 0-31 of PFRA
    0004    4 Signed       2 *              Bits 32-47 of PFRA
    0006    6 Bitstring    1 VPGGPSTA       Bits 48-51 of 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.
              .... 1..1      PAGGSMBZ       X'09' Must be zero in any valid
                                            PTE
              .... .1..      PAGGINVA       X'04' PTE is invalid: I-bit. To
                                            turn off this bit, SHORT pg.
                                            serialization must be held unless
                                            the bit is being turned off by
                                            HPMA or by fastpath resolve which
                                            require only PCLONLY
              .... ..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 a PGS64 (PGSTE)
    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 PGSTE
    0804 2052 Signed       4 VPGGPGS1       Word 1 of 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. Can be changed
                                            with PCLONLY page serialization
                                            by tasks allowed to use PCLONLY.
                                            Set by page fault fastpath.
              .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 >>PGSPGMIO was
                                            PGSIO1ST, PGSIO2ND
              .... .1..      PGSPGMIO       X'04' Indicates that pageable
                                            PGMBK I/O has not completed (PTRM
                                            page). Set when the first I/O
                                            completion interrupt is
                                            processed, reset when the second
                                            I/O completion interrupt is
                                            processed. Note the I/O can
                                            complete in either order.
                                            >>PGSPGMIM was PGSIOMSK
    0803 2051 Bitstring    1 VPGGSSTA       Virtual Page Status bits
    0803 2051 Bitstring    1 VPGGMSTA       Virtual Page (PGMBK) Status bits
    0804 2052 Signed       4 *              Reserved
    0804 2052 Bitstring    1 VPGGSB4        Virtual Page Status (Byte 4)
              1... ....      PGSZBIT        X'80' Page-content-logically zero
                                            bit Only meaningful when the PTE
                                            is invalid.
              ..1. ....      PGSCLASS       X'20' The page class specifies
                                            which Delta-pinned-page-count
                                            array is to be used in
                                            maintaining pinned page counts.
                                            Page class 0 (bit is 0) specifies
                                            the DPPCA for base address space
                                            pages owned by user. Page class 1
                                            (bit is 1) specifies NSS/DCSS
                                            imbedded shared pages. The page
                                            class 0 DPPCA resides in the
                                            ASCBK and is pointed to by
                                            SIEDPPCAO in the format-2 state
                                            descriptor (SI2BK). The page
                                            class 1 DPPCA resides resides in
                                            RSMBK and is pointed to by
                                            PFXDPPCAO in the prefix area.
              ...1 ....      PGSOVFLW       X'10' The pin count (PGSPINCT)
                                            has overflowed and the current
                                            value does not represent the
                                            total pin count. The remainder of
                                            the total pin count is contained
                                            in both PGSOVFL1 (a one bit pin
                                            count overflow used to control
                                            hardware interception) and
                                            ASAOVFLW in the ASATE). PTE must
                                            be valid. Can be modified with
                                            PCLONLY page serialization by
                                            tasks allowed to use PCLONLY. Set
                                            by pin/unpin fastpaths,
                                            translation paths, and no-owned
                                            functions.
              .... 1...      PGSPROCL       X'08' Indicates page is on the
                                            processed list. Turned on by
                                            machine or fast path processing
                                            when corresponding FRMTE is put
                                            on processed list. Turned off by
                                            HCPPLP processed list processing.
                                            Can be modified with PCLONLY page
                                            serialization by tasks allowed to
                                            use PCLONLY. Set by HPMA or
                                            fastpath validate page.
              .... .1..      PGSCONRP       X'04' Indicates a
                                            content-replacement operation
                                            occurred on an HPMA Resolve host
                                            page function. Can be modified
                                            with PCLONLY page serialization
                                            by tasks allowed to use PCLONLY.
                                            Set by HPMA or fastpath validate
                                            page.
              .... ..1.      PGSUS0         X'02'
              .... ...1      PGSUS1         X'01'
              .... ..11      PGSUS          PGSUS0+PGSUS1
              .... ....      PGSUSS         0
              .... ...1      PGSUSU         1
              .... ..1.      PGSUSP         2
              .... ..11      PGSUSV         3
    0805 2053 Bitstring    1 VPGGSB5        Virtual Page Status (Byte 5)
    0806 2054 Bitstring    1 VPGGSB6        Virtual Page Status (Byte 6)
    0807 2055 Bitstring    1 VPGGSB7        VPS (Byte 7) - Pin Count
            Mapping for a ASA64 (ASATE)
    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 ASATE
    1004 4100 Signed       4 VPGGASA1       Word 1 of 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.
    1004 4100 Signed       2 *              Reserved for IBM use
    1006 4102 Signed       2 VPGGOVFL       Count of the number of 128 pin-
                                            count overflow increments. The
                                            pin count for a page is kept in
                                            PGSPINCT, which is only 1 byte in
                                            length. If that overflows,
                                            ASAOVFLW is incremented and
                                            represents 128 pins.

#### 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          |                           |
    *     +---------------------------+                           |
    *     |                       VPGGXSTS                        |
    *     |                                                       |
    *     +---------------------------+------+--------------------+
    *  18 |///////////////////////////|//////| 1D
    *     +---------------------------+------+
    *
    *** 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 |///////////////////////////|
    *                                 +---------------------------+
    * 808
    *
    *** Overlay for VPGGPGS1 in VPG64

    *** Overlay for VPGGPGS1 in VPG64
    *
    *                                 +------+------+------+------+
    * 800 ...                     804 |:GSB4 |:GSB5 |:GSB6 |:GSB7 |
    *                                 +------+------+------+------+
    * 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

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

#### VPG64 Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    PAGGINVA       0006 04
    PAGGPROT       0006 02
    PAGGSMBZ       0006 09
    PAGGSXVA       0006 05
    PGSALLOC       0802 10
    PGSCLASS       0804 20
    PGSCONRP       0804 04
    PGSFIXED       0802 08
    PGSGCH         0801 02
    PGSGREF        0801 04
    PGSGUEST       0801 06
    PGSHOST        0801 60
    PGSINVAL       0802 80
    PGSOVFLW       0804 10
    PGSPCL         0801 80
    PGSPGMIO       0802 04
    PGSPROCL       0804 08
    PGSRCPHC       0801 20
    PGSRCPHR       0801 40
    PGSSHARE       0802 40
    PGSUS          0804 03
    PGSUSP         0804 02
    PGSUSS         0804 00
    PGSUSU         0804 01
    PGSUSV         0804 03
    PGSUS0         0804 02
    PGSUS1         0804 01
    PGSZBIT        0804 80
    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
    VPGGAVOL       1003
    VPGGMSTA       0803
    VPGGNEXT       0008
    VPGGOVFL       1006
    VPGGPAG        0000
    VPGGPGS        0800
    VPGGPGST       0800
    VPGGPGS0       0800
    VPGGPGS1       0804
    VPGGPLNK       0000
    VPGGPNTR       0000
    VPGGPSTA       0006
    VPGGPTE        0000
    VPGGPTE0       0000
    VPGGPTE1       0004
    VPGGPTRM       1004
    VPGGSB4        0804
    VPGGSB5        0805
    VPGGSB6        0806
    VPGGSB7        0807
    VPGGSFLG       0802
    VPGGSNTR       0800
    VPGGSRCP       0801
    VPGGSSTA       0803
    VPGGSVKY       0800
    VPGGVRSF       0800
    VPGGXSBN       0000
    VPGGXSTS       0004

This information is based on z/VM V5R2.0. Last updated on 12 Apr 2006 at 17:39:45 EDT.
Copyright IBM Corporation, 1990, 2005