ASCBK | Back to Index page

| Prolog Control Block Contents ASCBK 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.

ASCBK Prolog | Top of page

     NAME       : HCPASCBK
     DESCRIPTION: Address-Space-Control Block
     DSECT      : ASCBK
     FUNCTION   : Contain information about an address space.
                  The ASCBK is essentially CP's software extension
                  to the ASN-second-table entry (ASTE) describing
                  the address space.
     LOCATED BY : ASTASCBK field of the ASTE defining the address space
     CREATED BY : HCPASMCR
     DELETED BY : HCPASMDS
     SERIALIZED : Many fields in the ASCBK are static for the life of
                  the address space.  Most of the rest of them are
                  serialized by the ASCBK lock, the lockword for which
                  is at ASCLOCK.
                  Various fields are serialized by:
                  - ASCBK lock (ASCLOCK)
                  - MP Defer
                  - Console-function mode
                  - XSTSTATL
     RELOCATION CONSIDERATIONS : The address spaces associated with a relocating
                  guest are constructed on the destination system by
                  calling HCPASMCR on the destination.  The attributes
                  of the spaces are sent over during Storage
                  Eligibility Checking in the Address Space Data
                  Array (ADABK) and the VDISK Data Block (VDIBK).
                  In addition, the cumulative historical counts
                  kept in the ASCBK are also sent to the destination
                  system. These values are transmitted during
                  relocation in order to maintain relatively consistent
                  information in the responses to the INDICATE USER
                  and INDICATE SPACES commands.
                  - for VDISKs, the counters are sent during relocation
                  of the I/O configuration via the LGRVDEV block
                  - for the base address space, the counters are sent
                  at the end of the Memory Move in the Address Space
                  Data Area (RLMAS).
     COMMENTS   : The ASCBK must reside on a doubleword boundary.
                  The ASCBK is not a hardware architected block.

ASCBK Control Block Content | Top of page

     ASCBK DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      ASCBK          Address-Space-Control Block
          Address space management area.
          This area contains fields used to manage and locate the
          address space itself.  All fields in this area are
          serialized by the ASCBK lock (the lockword at ASCLOCK)
          unless specifically noted otherwise.
    0000    0 Address      4 ASCOFPNT       Host Logical Address Forward
                                            pointer to next ASCBK in chain of
                                            ASCBKs anchored from VMDASCBK of
                                            the owner's base VMDBK. This
                                            chain defines what address spaces
                                            are owned by the VMDBK.
                                            SYSTEM-owned spaces are anchored
                                            from the SYSTEM VMDBK. This field
                                            is serialized by the owner's
                                            ASCBK-queue lock (VMDASCLK). The
                                            chain is ended by a forward
                                            pointer of zero.
    0004    4 Address      4 ASCSFPNT       Host Logical Address Forward
                                            pointer to next ASCBK in the
                                            chain of ASCBKs anchored from
                                            RSASHRSP in HCPRSM. This is the
                                            chain of shareable address
                                            spaces, and is serialized by the
                                            lock at RSASHRLK. The chain is
                                            ended by a forward pointer of
                                            zero.
    0008    8 Address      4 ASCSBPNT       Host Logical Address Backward
                                            pointer to previous ASCBK in the
                                            chain of ASCBKs anchored from
                                            RSASHRSP in HCPRSM. The ASCSBPNT
                                            field of the first ASCBK in the
                                            chain is zeros.
    000C   12 Signed       4 ASCSEQNO       r-access sequence number,
                                            incremented on address space
                                            reset to match the ASTE sequence
                                            number (ASTSN). r-access i-ASITs
                                            (which use this sequence number)
                                            are sensitive to address space
                                            reset operations.
    0010   16 Character   32 ASCSPCID (0)   Space identification:
    0010   16 Character    8 ASCUSRID       Owning userid, padded on right
                                            with blanks.
    0018   24 Character   24 ASCNAME        Address space name, padded on
                                            right with blanks.
    0030   48 Address      4 ASCSNTBK       Host Logical Address Pointer to
                                            owning SNTBK (ASCTSNT=1)
    0034   52 Address      4 ASCASTEr       Host Real Address Pointer to
                                            ASN-Second-Table Entry (ASTE) for
                                            the address space. Serialized by
                                            task ownership at creation,
                                            thereafter unchanged until space
                                            is destroyed.
    0038   56 Dbl-Word     8 ASCEASIT (0)   ASCBK e-ASIT.
    0038   56 Address      4 ASCASTEl       Host Logical Address Pointer to
                                            ASN-Second-Table Entry ASCASTEr
                                            <- LoadRealAddress(ASCASTEl)
    003C   60 Signed       4 ASCSCRSN       Address space creation sequence
                                            number.
    0040   64 Address      4 ASCSPIBK       Host Logical Address Pointer to
                                            chain of SPIBKs designating which
                                            users are permitted to attach
                                            this space to their guest-use
                                            access list. This field is
                                            serialized by the
                                            space-permission- manager lock
                                            (RSASPMLK in HCPRSMCM).
    0044   68 Address      4 ASCOWNER       Host Logical Address Pointer to
                                            (base) VMDBK of owning virtual
                                            configuration, or SYSTEM VMDBK if
                                            CP owned.
    0048   72 Dbl-Word     8 ASCLOCK (3)    Lockword for shared/exclusive
                                            defer lock, protecting fields in
                                            the ASCBK and ASTE. For System
                                            Utility address spaces managed by
                                            HCPHAMAP and HCPHAMDP and
                                            HCPHSURO, ASCLOCK exclusive is
                                            sufficient to invalidate a STE
                                            without SEGTRANS. A share of
                                            ASCLOCK must be obtained *before*
                                            trying to obtain SEGTRANS when
                                            validating the STE.
    0060   96 Dbl-Word     8 ASCHIBYT       The highest addressable byte of
                                            storage in this address space.
                                            The "address limit" of the
                                            address space in bytes is one
                                            greater than this value. Since
                                            X'FFFFFFFF_FFFFFFFF' is a valid
                                            address in z/Arch, code must
                                            check for wrap-to-zero when
                                            adding one to ASCHIBYT to
                                            calculate the "address limit" of
                                            the address space in bytes. For
                                            the guest base address space,
                                            this value should be copied to
                                            SIEGMSLM in each VMDBK in the
                                            virtual configuration. See
                                            HCPUVBAS.
    0068  104 Dbl-Word     8 ASCDEFSZ       Defined storage size in
                                            addressable bytes, minus one. If
                                            DEF STOR CONFIG was used to
                                            define multiple discontiguous
                                            extents of addressable defined
                                            storage, this field contains the
                                            sum of the sizes in bytes of all
                                            of the individual extents (minus
                                            one). Minus one notation used so
                                            that a total size of 16 Exabytes
                                            may be represented without
                                            ambiguity (as
                                            x'FFFFFFFF_FFFFFFFF').
    0070  112 Signed       4 *              Reserved for IBM use
    0074  116 Bitstring    1 ASCSTATE       Flags indicating current state
                                            Serialized by holding ASCLOCK
                                            exclusive, the owning VMDBK's
                                            PTIL exclusive, AND by Console
                                            Function mode on the owning user.
              1... ....      ASCSHARE       X'80' ASCSHARE At least one
                                            configuration other than the
                                            owner has permission to access
                                            this address space.
              .1.. ....      ASCPUBLC       X'40' ASCPUBLC Any user may
                                            attach this address space to
                                            their guest-use access list for
                                            read/only access.
              ..1. ....      ASCE1ATT       X'20' ASCE1ATT Storage element 1
                                            is Attached SCLP ATTACH ELEMENT
                                            performed
              ...1 ....      ASCE1SBY       X'10' ASCE1SBY Storage element 1
                                            is Standby SCLP ATTACH ELEMENT
                                            not performed ASCEL1st non-zero
              .... 1...      ASCE1RSV       X'08' ASCE1RSV Storage element 1
                                            is Reserved SCLP ATTACH ELEMENT
                                            not performed ASCEL1st zero
                                            ASCEL1rv non-zero
              ..11 1...      ASCE1DEF       ASCE1ATT+ASCE1SBY+ASCE1RSV
                                            ASCE1DEF Storage element 1 is
                                            defined (may be Reserved,
                                            Standby, or Attached)
              .... ..1.      ASCRUSYS       X'02' ASCRUSYS DPPCA rollup is to
                                            be performed using the system
                                            VMDBK rather than the guest's
                                            VMDBK. This generally corresponds
                                            to ASCSHARE, except during
                                            address space isolate processing.
              .... ...1      ASCMDEXT       X'01' ASCMDEXT DEFINE STORAGE
                                            CONFIG has been used to define
                                            multiple discontiguous
                                            addressable extents for this
                                            address space. The ASCSTCFG area
                                            contains the storage
                                            configuration definition.
    0075  117 Bitstring    1 ASCTYPE        Code indicating type of address
                                            space These are assigned as bits,
                                            but only one bit will ever be
                                            set. This is done to allow code
                                            to test for combinations with one
                                            instruction.
              1... ....      ASCTUSER       X'80' ASCTUSER A user's base
                                            address space
              .1.. ....      ASCTDATA       X'40' ASCTDATA A data space
                                            created by user request through
                                            diagnose x'23C'
              ..1. ....      ASCTSYSX       X'20' ASCTSYSX The
                                            system-execution address space
              ...1 ....      ASCTSYSU       X'10' ASCTSYSU A system utility
                                            address space
              .... .1..      ASCTSNT        X'04' ASCTSNT An SNTBK "address
                                            space"
    0076  118 Bitstring    1 ASCFRMCD       Frame use code for this address
                                            space
    0077  119 Bitstring    1 ASCKEY         Bits 0-7 are the key with which
                                            to initialize pages in the
                                            address space.
    0078  120 Signed       4 ASCIACCT       Count of i-access pages in the
                                            address space which are locked or
                                            under (possible loss of control)
                                            translation through this ASCBK.
    007C  124 Signed       4 ASCITRCT       Count of in-process i-access
                                            manual translations in the
                                            address space.
    0080  128 Signed       4 ASCRTRCT       Count of in-process r-access
                                            manual translations in the
                                            address space.
    0084  132 Signed       4 *              Reserved for IBM use
    0088  136 Address      4 ASCTYPTR       Host Logical Address Pointer to
                                            address space type specific
                                            control block (PTRMB for PTRM
                                            address spaces). The address
                                            space type specific control block
                                            must itself contain a CP use
                                            Address space Allocation block
                                            (CAABK) at offset zero.
    008C  140 Bitstring    1 ASCFOLST       Flags indicating what Frame Owned
                                            list (Owning VMDBK UFO, or
                                            Shared) frames are to be put on.
              1... ....      ASCOUFO        X'80' ASCOUFO Frames for this
                                            address space are to be placed on
                                            the owning VMDBK's UFO list.
              .1.. ....      ASCSFO         X'40' ASCSFO Frames for this
                                            address space are to be placed on
                                            the Shared Frame Owned (SFO)
                                            list.
          WARNING: There is code in various places that checks the
          address space sub-type flag value without first checking
          address space type flag, so be very careful to avoid
          duplication when defining new sub-types.
    008D  141 Bitstring    1 ASCSUTYP       Flags indicating address space
                                            sub-type.
              1... ....      ASCUPTRM       X'80' A PTRM address space
                                            (sub-type of type ASCTSYSU).
              .1.. ....      ASCUPREF       X'40' A preferred address space
                                            (sub-type of type ASCTUSER).
              ..1. ....      ASCUVDSK       X'20' A VDISK address space
                                            (sub-type of type ASCTSYSU).
              ...1 ....      ASCUFTC        X'10' A full track cache address
                                            space (sub-type of ASCTSYSU)
              .... 1...      ASCUCONN       X'08' The Connectivity (aka ISFC)
                                            address space (sub-type of type
                                            ASCTSYSU).
              .... .1..      ASCUIDNT       X'04' The System-Identity address
                                            space, which identity maps all
                                            storage below 2G with DAT tables
                                            (sub-type of ASCTSYSU).
              .... ..1.      ASCUREAL       X'02' The System-Real address
                                            space, which identity maps all of
                                            real storage (including real
                                            storage above 2G) using an RSD
                                            (sub-type of ASCTSYSU).
    008E  142 Bitstring    1 ASCMISC        Miscellaneous flag bits.
                                            Modification of these bits is
                                            serialized by holding the ASCLOCK
                                            exclusive.
              1... ....      ASCDSTRY       X'80' When a release is part of
                                            an address space destroy, this
                                            bit is set. This bit indicates
                                            that the address space destroy
                                            thread holds the ASCLOCK
                                            exclusive. When this bit is ON
                                            subsequent code that is part of
                                            the thread can assume the lock is
                                            held exclusive. This bit is set
                                            after the ASCLOCK is acquired
                                            exclusive and prior to the lock
                                            being destroyed.
              .1.. ....      ASCRELOC       X'40' This address space is being
                                            relocated via the VMRELOCATE
                                            process.
              ..1. ....      ASCRELSRC      X'20' When ASCRELOC is one, this
                                            bit is valid and indicates the
                                            direction of the move. When one,
                                            this is the source/outbound
                                            ASCBK. When zero, this is a
                                            destination/inbound ASCBK.
              ...1 ....      ASCSHVDK       X'10' Shareable vdisk (defined in
                                            user directory rather than by
                                            DEFINE command)
    008F  143 Bitstring    1 *              Reserved for IBM use
    0090  144 Signed       4 ASCMSO         Main Storage Origin for preferred
                                            guest base address space. Only
                                            valid when ASCTYPE = ASCTUSER and
                                            ASCSUTYP = ASCUPREF.
    0094  148 Signed       4 ASCCTSPI       Count of users permitted to this
                                            address space. Equal to the
                                            number of SPIBKs on the ASCSPIBK
                                            queue. Serialized by the Space
                                            Permission Manager lock (RSASPMLK
                                            in HCPRSAMP).
          End of Address Space management area
          Address space statistics area.
          Current usage information for this address space
             Delta-Pinned-Page-Count Array (DPPCA) for page class 0
             Used by both hardware and software to maintain pinned
             page counts for page class 0 pages.  Page class 0 is
             used for base address space pages owned by the user. It's
             pointed to by the class 0 Delta-Pinned-Page-Count-Array
             Origin in the SIEBX, SIEDPPCAO. The page class 1
             array is used for NSS/DCSS imbedded shared pages and
             resides in the RSMBK.
    0098  152 Dbl-Word     8 ASCDPPCA (0)
    0098  152 Signed       4 ASCDPPB        Delta-pinned-page-count for all
                                            class 0 pages pinned below 2G
    009C  156 Signed       4 ASCDPPA        Delta-pinned-page-count for all
                                            class 0 pages pinned above 2G
    00A0  160 Signed       4 ASCCTPRS       Count of resident pages < 2G
                                            The following fields,
                                            ASCCTPLK/ASCCTPLKA, which contain
                                            counts of frames locked in
                                            absolute, cannot be relied upon
                                            to be instantaneously correct.
                                            These counts are modified by the
                                            DPPCA
                                            (Delta-Pinned-Page-Count-Array)
                                            roll-up routine which harvests
                                            the DPPCA counts and rolls them
                                            into these counts at specific
                                            times. In between calls, these
                                            counts may not reflect pins that
                                            have occurred or may not reflect
                                            unpins that have occurred. Care
                                            must be taken to ensure code that
                                            references these fields has no
                                            dependency on instantaneous
                                            correctness. When referencing a
                                            private address space, the counts
                                            can be made accurate by calling
                                            the HCPLALRU DPPCA rollup routine
                                            since the counts are private per
                                            space. However, for shared
                                            address spaces, calling HCPLALRU
                                            still does not guarantee the
                                            counts are completely accurate
                                            because HCPLALRU rolls up DPPCA
                                            counts for only the R11 user.
                                            Other users may also have
                                            outstanding pins/unpins that are
                                            not included.
    00A4  164 Signed       4 ASCCTPLK       Count of locked pages <2G
    00A8  168 Signed       8 ASCCTPLKA      Count of locked pages >2G
    00B0  176 Signed       4 ASCCTPGS       Count of paging slots.
    00B4  180 Signed       4 ASCCTXBK       Count of xstore blocks in this
                                            address space. XSTSTATL must be
                                            held to update this field.
    00B8  184 Signed       4 *              Reserved for ASCCTPRG expansion
    00BC  188 Signed       4 ASCCTPRG       Count of resident pages >= 2G
    00C0  192 Signed       4 ASCCTINS       Count of instantiated pages, i.e.
                                            the total number of unique pages
                                            regardless of where they reside
                                            in the storage hierarchy. Compare
                                            & Swap to update. This field is
                                            applicable to ASCTUSER, ASCTDATA,
                                            & ASCTSNT spaces only, or
                                            ASCTSYSU base space for the
                                            SYSTEM VMDBK
    00C4  196 Signed       4 *              Reserved for IBM use
    00C8  200 Signed       4 ASCHLLC        Count of pages locked in host
                                            logical storage
    00CC  204 Signed       4 ASCHLRC        Host logical resident count
                                            Updates to this field are
                                            serialized by the SXSPM Queue
                                            Lock - RSASXQLK
    00D0  208 Signed       4 ASCCTIBRb2g    Count of IBR pages on the frame
                                            owned list that are backed by
                                            frames < 2G. Compare & Swap to
                                            update.
    00D4  212 Signed       4 ASCCTIBRa2G    Count of IBR pages on the frame
                                            owned list that are backed by
                                            frames > 2G. Compare & Swap to
                                            update.
    00D8  216 Signed       4 ASCCTAGLb2g    Count of IBR pages on the global
                                            aging list that are backed by
                                            frames < 2G. Hold RSAAGINL to
                                            update.
    00DC  220 Signed       4 ASCCTAGLa2g    Count of IBR pages on the global
                                            aging list that are backed by
                                            frames > 2G. Hold RSAAGINL to
                                            update.
    00E0  224 Signed       4 ASCCTRABISb2g  Count of non-faulted pages read
                                            in by a block read, made IBR,
                                            currently on the frame owned or
                                            global aging list, and backed by
                                            frames < 2G. Compare & Swap to
                                            update.
    00E4  228 Signed       4 ASCCTRABISa2g  Count of non-faulted pages read
                                            in by a block read, made IBR,
                                            currently on the frame owned or
                                            global aging list, and backed by
                                            frames > 2G. Compare & Swap to
                                            update.
          RESERVED counts for ASCTYPE=ASCTSNT spaces.
    00E8  232 Signed       4 *              Reserved for ASCCTRSV expansion
    00EC  236 Signed       4 ASCCTRSV       RESERVED frame count. Updates are
                                            serialized by the SET RESERVED
                                            Lock - RSARSDLK.
    00F0  240 Signed       4 *              Reserved for IBM use
    00F4  244 Signed       4 ASCDSRSV       Count of times Demand Scan could
                                            not move any pages from the SUFO
                                            to the Aging List for this NSS or
                                            DCSS because doing so would
                                            violate its RESERVED setting.
          End of RESERVED counts for ASCTYPE=ASCTNT spaces.
          Cumulative historical counts, when address space is private
    00F8  248 Signed       4 ASCCPPST       Count of private address space
                                            pages stolen
    00FC  252 Signed       4 ASCCPPGR       Count of private address space
                                            pages read from DASD.
    0100  256 Signed       4 ASCCPPGW       Count of private address space
                                            pages written to DASD.
    0104  260 Signed       4 ASCCPXRD       Count of private address space
                                            pages read from XSTORE.
    0108  264 Signed       4 ASCCPXWT       Count of private address space
                                            pages written to XSTORE.
    010C  268 Signed       4 ASCCPMIG       Count of private address space
                                            pages migrated by CP from XSTORE
                                            to DASD.
    0110  272 Signed       4 ASCCPINT       Count of private instantiated
                                            pages. Updated via CS.
    0114  276 Signed       4 ASCCPREL       Count of private pages whose
                                            frames were reclaimed without
                                            preserving the page content
                                            because of the guest page state
                                            (that is, CMM2 state or contents
                                            were released by the guest).
                                            Updated via CS.
    0118  280 Signed       4 ASCCPINV       Count of private pages made IBR.
                                            Updated while holding VMDUFOLK.
    011C  284 Signed       4 ASCCPPFI       Count of private IBR pages that
                                            were revalidated while on the
                                            frame owned list. Updated while
                                            holding VMDUFOLK.
    0120  288 Signed       4 ASCCPPFA       Count of private IBR pages that
                                            were revalidated while on the
                                            global aging list. Updated while
                                            holding RSAAGINL.
    0124  292 Signed       4 ASCCPFRY       Count of private IBR pages on the
                                            global aging list that were
                                            already backed on auxiliary
                                            before the frames needed to be
                                            reclaimed. Updated while holding
                                            RSAAGINL.
    0128  296 Signed       4 ASCCPFNR       Count of private IBR pages on the
                                            global aging list that were
                                            written to XSTORE or auxiliary
                                            storage immediately prior to the
                                            frames being reclaimed. Updated
                                            while holding RSAAGINL.
    012C  300 Signed       4 ASCCPXRL       Count of XSTORE blocks released
                                            by migration when the private
                                            page contents were already in
                                            auxiliary storage. Updated by
                                            migration task (on master
                                            processor).
          Cumulative historical counts, when address space is shared
    0130  304 Signed       4 ASCPTRSH       Cumulative count of page
                                            translations for shared pages.
    0134  308 Signed       4 ASCCSPST       Count of shared address space
                                            pages stolen
    0138  312 Signed       4 ASCCSPGR       Count of shared address space
                                            pages read from DASD.
    013C  316 Signed       4 ASCCSPGW       Count of shared address space
                                            pages written to DASD.
    0140  320 Signed       4 ASCCSXRD       Count of shared address space
                                            pages read from XSTORE.
    0144  324 Signed       4 ASCCSXWT       Count of shared address space
                                            pages written to XSTORE.
    0148  328 Signed       4 ASCCSMIG       Count of shared address space
                                            pages migrated by CP from XSTORE
                                            to DASD.
    014C  332 Signed       4 ASCCSINT       Count of shared instantiated
                                            pages.
    0150  336 Signed       4 ASCCSREL       Count of shared pages whose
                                            frames were reclaimed without
                                            preserving the page content
                                            because of the guest page state
                                            (that is, CMM2 state or contents
                                            were released by the guest).
    0154  340 Signed       4 ASCCSINV       Count of shared pages made IBR.
    0158  344 Signed       4 ASCCSPFI       Count of shared IBR pages that
                                            were revalidated while on the
                                            frame owned list.
    015C  348 Signed       4 ASCCSPFA       Count of shared IBR pages that
                                            were revalidated while on the
                                            global aging list.
    0160  352 Signed       4 ASCCSFRY       Count of shared IBR pages on the
                                            global aging list that were
                                            already backed on auxiliary
                                            before the frames needed to be
                                            reclaimed.
    0164  356 Signed       4 ASCCSFNR       Count of shared IBR pages on the
                                            global aging list that were
                                            written to XSTORE or auxiliary
                                            storage immediately prior to the
                                            frames being reclaimed.
    0168  360 Signed       4 ASCCSXRL       Count of XSTORE blocks released
                                            by migration when the shared page
                                            contents were already in
                                            auxiliary storage.
    016C  364 Address      4 *              Reserved for IBM use
          End of address space statistics area.
          The following fields are serialized by the available list
          replenishment demand scan lock.  They are used to sort the
          queue of stolen FRMTEs by address space (for user address
          space frames, VDISK address space frames, and NSS/DCSS
          shared segment frames) and by virtual address megabyte
          (for NSS/DCSS shared segment frames only).
    0170  368 Address      4 ASCSTLNX       Host Logical Address Address of
                                            the next ASCBK for an address
                                            space from which pages were
                                            stolen in this iteration of the
                                            steal task. Each iteration will
                                            initialize this field to
                                            x'FFFFFFFF'. When the entire
                                            queue of FRMTEs is sorted (by
                                            address space), the last ASCBK in
                                            this chain will have x'FFFFFFFF'
                                            in this field.
    0174  372 Address      4 *              Reserved for IBM use
    0178  376 Address      8 ASC1STFRG      Host Logical Address Address of
                                            the first FRMTE that was stolen
                                            from this address space in this
                                            iteration of the steal task, and
                                            anchor of the queue of all FRMTEs
                                            stolen from this address space by
                                            this iteration of the steal task
                                            (queued by FRMTE field FRMFPNTG).
                                            Each iteration will initialize
                                            this field to -1, and a FRMTE
                                            FRMFPNTG value of -1 indicates
                                            that it is the last FRMTE on the
                                            queue.
    0180  384 Address      8 ASCLSTFRG      Host Logical Address Address of
                                            the last (processed) FRMTE that
                                            was stolen from this address
                                            space in this iteration of the
                                            steal task. Each iteration will
                                            initialize this field to -1 and a
                                            FRMTE FRMFPNTG value of -1
                                            indicates that it is the last
                                            FRMTE on the queue. Only used
                                            when sorting FRMTEs for normal
                                            user pages, which do not need to
                                            be sorted by segment (virtual
                                            address megabyte). For NSS/DCSS
                                            shared segment page FRMTEs, use
                                            ASC1STPG instead.
    0188  392 Address      8 ASC1STPG       Host Real Address Address of the
                                            first PGMBK for this address
                                            space from which pages were
                                            stolen in this iteration of the
                                            steal task, and anchor of the
                                            queue of all PGMBKs for this
                                            address space from which pages
                                            were stolen in this iteration of
                                            the steal task (queued by PGMBK
                                            field PGMGNPGM). Each iteration
                                            will initialize this field to all
                                            FFs, and all FFs in a PGMBK
                                            PGMGNPGM field indicates that it
                                            is the last PGMBK on the list.
                                            Only used when sorting FRMTEs for
                                            NSS/DCSS shared segment pages,
                                            which must be sorted by segment
                                            (virtual address megabyte). For
                                            normal user page FRMTEs, use
                                            ASCLSTFRG instead.
    0190  400 Address      8 ASCLSTPG       Host Real Address Address of the
                                            last PGMBK for this address space
                                            from which pages were stolen in
                                            this iteration of the steal task.
                                            Each iteration will initialize
                                            this field to all FFs, and all
                                            FFs in a PGMBK PGMGNPGM field
                                            indicates that it is the last
                                            PGMBK on the list. Only used when
                                            sorting FRMTEs for NSS/DCSS
                                            shared segment pages, which must
                                            be sorted by segment (virtual
                                            address megabyte).
          Region Translation Cache
             ASCR0STD, ASCR0RFT, ASCR0RST, and ASCR0RTT, are in
             ASCE format, that is, the bits which define the table
             level are DT bits (level of the designated table), not
             R*TE format TT bits (which indicate the level of the
             table containing the R*TE).  Any ASCR0R*T fields
             corresponding to table levels higher than that
             designated by the current ASCE are set to zero.
             Serialization of these fields is as follows: For the
             entry designating the current highest level table for
             the address space (that is, the entry which matches the
             current ASCE), PTIL must be held exclusive.  For all
             lower level table entries, either PTIL must be held
             exclusive, or a share of PTIL must be held along with
             RTETRANS in the next higher level R*TE which designates
             the same table.
    0198  408 Dbl-Word     8 ASCR0STD       Host Real Address + other bits
                                            Rx=0 segment table designation
    01A0  416 Dbl-Word     8 ASCR0RFT       Host Real Address + other bits
                                            Rx=0 region first table
                                            designation
    01A8  424 Dbl-Word     8 ASCR0RST       Host Real Address + other bits
                                            Rx=0 region second table
                                            designation
    01B0  432 Dbl-Word     8 ASCR0RTT       Host Real Address + other bits
                                            Rx=0 region third table
                                            designation
    01B8  440 Dbl-Word     8 * (3)          Reserved for IBM use
    01D0  464 Signed       4 ASCMVABV       Number of times a page in this
                                            address space with a frame
                                            address < 2G was moved to a
                                            frame with address >= 2G.
    01D4  468 Signed       4 ASCMVB2G       Number of times a page in this
                                            address space was moved from a
                                            frame with address >= 2G to
                                            one < 2G.
    01D8  472 Signed       8 * (5)          Reserved for IBM use
          Address Space Storage Configuration area
          This array contains address extent information for each
          defined address extent.  For most address spaces, there
          will only be one extent defined, from 0 to ASCHIBYT.  If
          the DEFine STORage CONFIGuration command was used to
          define multiple discontiguous address extents, this array
          contains one additional entry for each additional address
          extent defined.  Up to eight extents are allowed, the
          first extent must begin at address zero.
          Individual array elements are mapped by STCONFIG DSECT.
          Array elements must be sorted in ascending virtual address
          order.  Address ranges must not overlap, and must not be
          contiguous.
              00000008       ASCSTELS       8 Number of elements in storage
                                            configuration array
    0200  512 Signed       4 ASCSTCAE       Number of additional storage
                                            configuration array elements used
                                            to represent the current storage
                                            config. Is also index of last
                                            used element. Element 0 is always
                                            used. Must be between 0 and
                                            ASCSTELS-1, inclusive.
    0204  516 Signed       4 *              Reserved for IBM use
    0208  520 Signed       8 * (0)
    0208  520 Bitstring  128 ASCSTCFG (0)   ASCSTCFG area contains ASCSTELS
                                            elements, two doublewords each
    0208  520 Signed       8 ASCSTCE0 (2)   ASCSTCFG element 0
              00000010       ASCSTLEN       *-ASCSTCE0 Length of one element
              0000000E       ASCWK          (ASCSTELS-1)*2
    0218  536 Signed       8 * (14)         Remaining elements
    0288  648 Address      4 ASCSTCMD       Host Logical Address Pointer to
                                            the GSDBK containing saved image
                                            of the storage configuration
                                            definition string as issued on
                                            the actual DEFine STORage
                                            CONFIGuration command
          Address Space Storage Element Data Area
          While a typical configuration would have at most 512
          address increments per element (if using a sufficiently
          large increment size), we must also allow for the
          artificial increment size of 1M regardless of total
          storage size.  For "DEF STOR 16E", this means that we
          would have 16E/M, or 16T increments.  This requires that
          we define ASCRNMAX as FD.  This also requires ASCEL0cf to
          be defined FD since all storage would be defined to be in
          element 0, and there would be no element 1.
          Changes to the "nbr increments" fields should be done
          under exclusive control of the ASCLOCK lock.
    028C  652 Signed       4 *              Reserved for IBM use The bit maps
                                            of assigned/unassigned address
                                            increments are valid ONLY if
                                            element 1 is defined.
          Element 0 can have 512 increments.
          Element 1 can have 512 increments.
          So we need 1024 bits.
          But we don't map 512 bits to each element.
            If element 0 has 'n' increments,
            then increment 'n+1' is the first of element 1.
    0290  656 Bitstring  128 ASCELbmp       Assigned address increments
    0310  784 Signed       8 ASCEL0cf       EL 0 nbr increments configured
    0318  792 Signed       2 ASCEL0st       EL 0 nbr increments standby
    031A  794 Signed       2 ASCEL0rs       EL 0 nbr increments reserved
    031C  796 Signed       2 ASCEL1cf       EL 1 nbr increments configured
    031E  798 Signed       2 ASCEL1st       EL 1 nbr increments standby
    0320  800 Signed       2 ASCEL1rs       EL 1 nbr increments reserved
    0322  802 Signed       2 *              Reserved for IBM use
    0324  804 Signed       4 *              Reserved for IBM use
    0328  808 Signed       8 ASCRNMAX       Maximum storage increment number
                                            Should be equal to the sum of
                                            ASCEL0cf + ASCEL0st + ASCEL0rs +
                                            ASCEL1cf + ASCEL1st + ASCEL1rs
    0330  816 Signed       8 ASCSTINC       Storage increment size:M
    0338  824 Dbl-Word     8 *              Reserved for IBM use
          End of ASCBK
    0340  832 Dbl-Word     8 ASC$END (0)    End of control block
              00000340       ASCLEN         *-ASCBK Length of ASCBK in bytes
              00000068       ASCSIZE        (ASCLEN+7)/8 Size of ASCBK in
                                            doublewords
          DSECT to map individual ASCSTCFG storage configuration
          elements

ASCBK Storage Layout | Top of page

    *** ASCBK - Address-Space-Control Block
    *
    *     +---------------------------+---------------------------+
    *   0 |         ASCOFPNT          |         ASCSFPNT          |
    *     +---------------------------+---------------------------+
    *   8 |         ASCSBPNT          |         ASCSEQNO          |
    *     +---------------------------+---------------------------+
    *  10 |                       ASCUSRID                        |
    *     +-------------------------------------------------------+
    *  18 |                                                       |
    *     =                       ASCNAME                         =
    *     |                                                       |
    *     +---------------------------+---------------------------+
    *  30 |         ASCSNTBK          |         ASCASTER          |
    *     +---------------------------+---------------------------+
    *  38 |         ASCASTEL          |         ASCSCRSN          |
    *     +---------------------------+---------------------------+
    *  40 |         ASCSPIBK          |         ASCOWNER          |
    *     +---------------------------+---------------------------+
    *  48 |                                                       |
    *     =                       ASCLOCK                         =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  60 |                       ASCHIBYT                        |
    *     +-------------------------------------------------------+
    *  68 |                       ASCDEFSZ                        |
    *     +---------------------------+------+------+------+------+
    *  70 |///////////////////////////|:STATE|:TYPE |:FRMCD|ASCKEY|
    *     +---------------------------+------+------+------+------+
    *  78 |         ASCIACCT          |         ASCITRCT          |
    *     +---------------------------+---------------------------+
    *  80 |         ASCRTRCT          |///////////////////////////|
    *     +---------------------------+------+------+------+------+
    *  88 |         ASCTYPTR          |:FOLST|:SUTYP|:MISC |//////|
    *     +---------------------------+------+------+------+------+
    *  90 |          ASCMSO           |         ASCCTSPI          |
    *     +---------------------------+---------------------------+
    *  98 |         ASCDPPB           |         ASCDPPA           |
    *     +---------------------------+---------------------------+
    *  A0 |         ASCCTPRS          |         ASCCTPLK          |
    *     +---------------------------+---------------------------+
    *  A8 |                      ASCCTPLKA                        |
    *     +---------------------------+---------------------------+
    *  B0 |         ASCCTPGS          |         ASCCTXBK          |
    *     +---------------------------+---------------------------+
    *  B8 |///////////////////////////|         ASCCTPRG          |
    *     +---------------------------+---------------------------+
    *  C0 |         ASCCTINS          |///////////////////////////|
    *     +---------------------------+---------------------------+
    *  C8 |         ASCHLLC           |         ASCHLRC           |
    *     +---------------------------+---------------------------+
    *  D0 |       ASCCTIBRB2G         |       ASCCTIBRA2G         |
    *     +---------------------------+---------------------------+
    *  D8 |       ASCCTAGLB2G         |       ASCCTAGLA2G         |
    *     +---------------------------+---------------------------+
    *  E0 |      ASCCTRABISB2G        |      ASCCTRABISA2G        |
    *     +---------------------------+---------------------------+
    *  E8 |///////////////////////////|         ASCCTRSV          |
    *     +---------------------------+---------------------------+
    *  F0 |///////////////////////////|         ASCDSRSV          |
    *     +---------------------------+---------------------------+
    *  F8 |         ASCCPPST          |         ASCCPPGR          |
    *     +---------------------------+---------------------------+
    * 100 |         ASCCPPGW          |         ASCCPXRD          |
    *     +---------------------------+---------------------------+
    * 108 |         ASCCPXWT          |         ASCCPMIG          |
    *     +---------------------------+---------------------------+
    * 110 |         ASCCPINT          |         ASCCPREL          |
    *     +---------------------------+---------------------------+
    * 118 |         ASCCPINV          |         ASCCPPFI          |
    *     +---------------------------+---------------------------+
    * 120 |         ASCCPPFA          |         ASCCPFRY          |
    *     +---------------------------+---------------------------+
    * 128 |         ASCCPFNR          |         ASCCPXRL          |
    *     +---------------------------+---------------------------+
    * 130 |         ASCPTRSH          |         ASCCSPST          |
    *     +---------------------------+---------------------------+
    * 138 |         ASCCSPGR          |         ASCCSPGW          |
    *     +---------------------------+---------------------------+
    * 140 |         ASCCSXRD          |         ASCCSXWT          |
    *     +---------------------------+---------------------------+
    * 148 |         ASCCSMIG          |         ASCCSINT          |
    *     +---------------------------+---------------------------+
    * 150 |         ASCCSREL          |         ASCCSINV          |
    *     +---------------------------+---------------------------+
    * 158 |         ASCCSPFI          |         ASCCSPFA          |
    *     +---------------------------+---------------------------+
    * 160 |         ASCCSFRY          |         ASCCSFNR          |
    *     +---------------------------+---------------------------+
    * 168 |         ASCCSXRL          |///////////////////////////|
    *     +---------------------------+---------------------------+
    * 170 |         ASCSTLNX          |///////////////////////////|
    *     +---------------------------+---------------------------+
    * 178 |                      ASC1STFRG                        |
    *     +-------------------------------------------------------+
    * 180 |                      ASCLSTFRG                        |
    *     +-------------------------------------------------------+
    * 188 |                       ASC1STPG                        |
    *     +-------------------------------------------------------+
    * 190 |                       ASCLSTPG                        |
    *     +-------------------------------------------------------+
    * 198 |                       ASCR0STD                        |
    *     +-------------------------------------------------------+
    * 1A0 |                       ASCR0RFT                        |
    *     +-------------------------------------------------------+
    * 1A8 |                       ASCR0RST                        |
    *     +-------------------------------------------------------+
    * 1B0 |                       ASCR0RTT                        |
    *     +-------------------------------------------------------+
    * 1B8 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////////////////////////////////|
    *     +---------------------------+---------------------------+
    * 1D0 |         ASCMVABV          |         ASCMVB2G          |
    *     +---------------------------+---------------------------+
    * 1D8 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////////////////////////////////|
    *     +---------------------------+---------------------------+
    * 200 |         ASCSTCAE          |///////////////////////////|
    *     +---------------------------+---------------------------+
    * 208 |                       ASCSTCE0                        |
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 218 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////////////////////////////////|
    *     +---------------------------+---------------------------+
    * 288 |         ASCSTCMD          |///////////////////////////|
    *     +---------------------------+---------------------------+
    * 290 |                                                       |
    *     =                       ASCELBMP                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 310 |                       ASCEL0CF                        |
    *     +-------------+-------------+-------------+-------------+
    * 318 |  ASCEL0ST   |  ASCEL0RS   |  ASCEL1CF   |  ASCEL1ST   |
    *     +-------------+-------------+-------------+-------------+
    * 320 |  ASCEL1RS   |/////////////|///////////////////////////|
    *     +-------------+-------------+---------------------------+
    * 328 |                       ASCRNMAX                        |
    *     +-------------------------------------------------------+
    * 330 |                       ASCSTINC                        |
    *     +-------------------------------------------------------+
    * 338 |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    *
    *** ASCBK - Address-Space-Control Block

ASCBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    ASC$END        0340
    ASCASTEl       0038
    ASCASTEr       0034
    ASCCPFNR       0128
    ASCCPFRY       0124
    ASCCPINT       0110
    ASCCPINV       0118
    ASCCPMIG       010C
    ASCCPPFA       0120
    ASCCPPFI       011C
    ASCCPPGR       00FC
    ASCCPPGW       0100
    ASCCPPST       00F8
    ASCCPREL       0114
    ASCCPXRD       0104
    ASCCPXRL       012C
    ASCCPXWT       0108
    ASCCSFNR       0164
    ASCCSFRY       0160
    ASCCSINT       014C
    ASCCSINV       0154
    ASCCSMIG       0148
    ASCCSPFA       015C
    ASCCSPFI       0158
    ASCCSPGR       0138
    ASCCSPGW       013C
    ASCCSPST       0134
    ASCCSREL       0150
    ASCCSXRD       0140
    ASCCSXRL       0168
    ASCCSXWT       0144
    ASCCTAGLa2g    00DC
    ASCCTAGLb2g    00D8
    ASCCTIBRa2G    00D4
    ASCCTIBRb2g    00D0
    ASCCTINS       00C0
    ASCCTPGS       00B0
    ASCCTPLK       00A4
    ASCCTPLKA      00A8
    ASCCTPRG       00BC
    ASCCTPRS       00A0
    ASCCTRABISa2g  00E4
    ASCCTRABISb2g  00E0
    ASCCTRSV       00EC
    ASCCTSPI       0094
    ASCCTXBK       00B4
    ASCDEFSZ       0068
    ASCDPPA        009C
    ASCDPPB        0098
    ASCDPPCA       0098
    ASCDSRSV       00F4
    ASCDSTRY       008E 80
    ASCEASIT       0038
    ASCELbmp       0290
    ASCEL0cf       0310
    ASCEL0rs       031A
    ASCEL0st       0318
    ASCEL1cf       031C
    ASCEL1rs       0320
    ASCEL1st       031E
    ASCE1ATT       0074 20
    ASCE1DEF       0074 38
    ASCE1RSV       0074 08
    ASCE1SBY       0074 10
    ASCFOLST       008C
    ASCFRMCD       0076
    ASCHIBYT       0060
    ASCHLLC        00C8
    ASCHLRC        00CC
    ASCIACCT       0078
    ASCITRCT       007C
    ASCKEY         0077
    ASCLEN         0340 00000340
    ASCLOCK        0048
    ASCLSTFRG      0180
    ASCLSTPG       0190
    ASCMDEXT       0074 01
    ASCMISC        008E
    ASCMSO         0090
    ASCMVABV       01D0
    ASCMVB2G       01D4
    ASCNAME        0018
    ASCOFPNT       0000
    ASCOUFO        008C 80
    ASCOWNER       0044
    ASCPTRSH       0130
    ASCPUBLC       0074 40
    ASCRELOC       008E 40
    ASCRELSRC      008E 20
    ASCRNMAX       0328
    ASCRTRCT       0080
    ASCRUSYS       0074 02
    ASCR0RFT       01A0
    ASCR0RST       01A8
    ASCR0RTT       01B0
    ASCR0STD       0198
    ASCSBPNT       0008
    ASCSCRSN       003C
    ASCSEQNO       000C
    ASCSFO         008C 40
    ASCSFPNT       0004
    ASCSHARE       0074 80
    ASCSHVDK       008E 10
    ASCSIZE        0340 00000068
    ASCSNTBK       0030
    ASCSPCID       0010
    ASCSPIBK       0040
    ASCSTATE       0074
    ASCSTCAE       0200
    ASCSTCE0       0208
    ASCSTCFG       0208
    ASCSTCMD       0288
    ASCSTELS       01D8 00000008
    ASCSTINC       0330
    ASCSTLEN       0208 00000010
    ASCSTLNX       0170
    ASCSUTYP       008D
    ASCTDATA       0075 40
    ASCTSNT        0075 04
    ASCTSYSU       0075 10
    ASCTSYSX       0075 20
    ASCTUSER       0075 80
    ASCTYPE        0075
    ASCTYPTR       0088
    ASCUCONN       008D 08
    ASCUFTC        008D 10
    ASCUIDNT       008D 04
    ASCUPREF       008D 40
    ASCUPTRM       008D 80
    ASCUREAL       008D 02
    ASCUSRID       0010
    ASCUVDSK       008D 20
    ASCWK          0208 0000000E
    ASC1STFRG      0178
    ASC1STPG       0188

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:27:00 EDT.
Copyright IBM Corporation, 1990, 2020