The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/xen/interface/grant_table.h

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    1 /******************************************************************************
    2  * grant_table.h
    3  *
    4  * Interface for granting foreign access to page frames, and receiving
    5  * page-ownership transfers.
    6  *
    7  * Permission is hereby granted, free of charge, to any person obtaining a copy
    8  * of this software and associated documentation files (the "Software"), to
    9  * deal in the Software without restriction, including without limitation the
   10  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
   11  * sell copies of the Software, and to permit persons to whom the Software is
   12  * furnished to do so, subject to the following conditions:
   13  *
   14  * The above copyright notice and this permission notice shall be included in
   15  * all copies or substantial portions of the Software.
   16  *
   17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   23  * DEALINGS IN THE SOFTWARE.
   24  *
   25  * Copyright (c) 2004, K A Fraser
   26  */
   27 
   28 #ifndef __XEN_PUBLIC_GRANT_TABLE_H__
   29 #define __XEN_PUBLIC_GRANT_TABLE_H__
   30 
   31 #include "xen.h"
   32 
   33 /*
   34  * `incontents 150 gnttab Grant Tables
   35  *
   36  * Xen's grant tables provide a generic mechanism to memory sharing
   37  * between domains. This shared memory interface underpins the split
   38  * device drivers for block and network IO.
   39  *
   40  * Each domain has its own grant table. This is a data structure that
   41  * is shared with Xen; it allows the domain to tell Xen what kind of
   42  * permissions other domains have on its pages. Entries in the grant
   43  * table are identified by grant references. A grant reference is an
   44  * integer, which indexes into the grant table. It acts as a
   45  * capability which the grantee can use to perform operations on the
   46  * granter’s memory.
   47  *
   48  * This capability-based system allows shared-memory communications
   49  * between unprivileged domains. A grant reference also encapsulates
   50  * the details of a shared page, removing the need for a domain to
   51  * know the real machine address of a page it is sharing. This makes
   52  * it possible to share memory correctly with domains running in
   53  * fully virtualised memory.
   54  */
   55 
   56 /***********************************
   57  * GRANT TABLE REPRESENTATION
   58  */
   59 
   60 /* Some rough guidelines on accessing and updating grant-table entries
   61  * in a concurrency-safe manner. For more information, Linux contains a
   62  * reference implementation for guest OSes (drivers/xen/grant_table.c, see
   63  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=drivers/xen/grant-table.c;hb=HEAD
   64  *
   65  * NB. WMB is a no-op on current-generation x86 processors. However, a
   66  *     compiler barrier will still be required.
   67  *
   68  * Introducing a valid entry into the grant table:
   69  *  1. Write ent->domid.
   70  *  2. Write ent->frame:
   71  *      GTF_permit_access:   Frame to which access is permitted.
   72  *      GTF_accept_transfer: Pseudo-phys frame slot being filled by new
   73  *                           frame, or zero if none.
   74  *  3. Write memory barrier (WMB).
   75  *  4. Write ent->flags, inc. valid type.
   76  *
   77  * Invalidating an unused GTF_permit_access entry:
   78  *  1. flags = ent->flags.
   79  *  2. Observe that !(flags & (GTF_reading|GTF_writing)).
   80  *  3. Check result of SMP-safe CMPXCHG(&ent->flags, flags, 0).
   81  *  NB. No need for WMB as reuse of entry is control-dependent on success of
   82  *      step 3, and all architectures guarantee ordering of ctrl-dep writes.
   83  *
   84  * Invalidating an in-use GTF_permit_access entry:
   85  *  This cannot be done directly. Request assistance from the domain controller
   86  *  which can set a timeout on the use of a grant entry and take necessary
   87  *  action. (NB. This is not yet implemented!).
   88  *
   89  * Invalidating an unused GTF_accept_transfer entry:
   90  *  1. flags = ent->flags.
   91  *  2. Observe that !(flags & GTF_transfer_committed). [*]
   92  *  3. Check result of SMP-safe CMPXCHG(&ent->flags, flags, 0).
   93  *  NB. No need for WMB as reuse of entry is control-dependent on success of
   94  *      step 3, and all architectures guarantee ordering of ctrl-dep writes.
   95  *  [*] If GTF_transfer_committed is set then the grant entry is 'committed'.
   96  *      The guest must /not/ modify the grant entry until the address of the
   97  *      transferred frame is written. It is safe for the guest to spin waiting
   98  *      for this to occur (detect by observing GTF_transfer_completed in
   99  *      ent->flags).
  100  *
  101  * Invalidating a committed GTF_accept_transfer entry:
  102  *  1. Wait for (ent->flags & GTF_transfer_completed).
  103  *
  104  * Changing a GTF_permit_access from writable to read-only:
  105  *  Use SMP-safe CMPXCHG to set GTF_readonly, while checking !GTF_writing.
  106  *
  107  * Changing a GTF_permit_access from read-only to writable:
  108  *  Use SMP-safe bit-setting instruction.
  109  */
  110 
  111 /*
  112  * Reference to a grant entry in a specified domain's grant table.
  113  */
  114 typedef uint32_t grant_ref_t;
  115 
  116 /*
  117  * A grant table comprises a packed array of grant entries in one or more
  118  * page frames shared between Xen and a guest.
  119  * [XEN]: This field is written by Xen and read by the sharing guest.
  120  * [GST]: This field is written by the guest and read by Xen.
  121  */
  122 
  123 /*
  124  * Version 1 of the grant table entry structure is maintained purely
  125  * for backwards compatibility.  New guests should use version 2.
  126  */
  127 #if __XEN_INTERFACE_VERSION__ < 0x0003020a
  128 #define grant_entry_v1 grant_entry
  129 #define grant_entry_v1_t grant_entry_t
  130 #endif
  131 struct grant_entry_v1 {
  132     /* GTF_xxx: various type and flag information.  [XEN,GST] */
  133     uint16_t flags;
  134     /* The domain being granted foreign privileges. [GST] */
  135     domid_t  domid;
  136     /*
  137      * GTF_permit_access: Frame that @domid is allowed to map and access. [GST]
  138      * GTF_accept_transfer: Frame whose ownership transferred by @domid. [XEN]
  139      */
  140     uint32_t frame;
  141 };
  142 typedef struct grant_entry_v1 grant_entry_v1_t;
  143 
  144 /* The first few grant table entries will be preserved across grant table
  145  * version changes and may be pre-populated at domain creation by tools.
  146  */
  147 #define GNTTAB_NR_RESERVED_ENTRIES     8
  148 #define GNTTAB_RESERVED_CONSOLE        0
  149 #define GNTTAB_RESERVED_XENSTORE       1
  150 
  151 /*
  152  * Type of grant entry.
  153  *  GTF_invalid: This grant entry grants no privileges.
  154  *  GTF_permit_access: Allow @domid to map/access @frame.
  155  *  GTF_accept_transfer: Allow @domid to transfer ownership of one page frame
  156  *                       to this guest. Xen writes the page number to @frame.
  157  *  GTF_transitive: Allow @domid to transitively access a subrange of
  158  *                  @trans_grant in @trans_domid.  No mappings are allowed.
  159  */
  160 #define GTF_invalid         (0U<<0)
  161 #define GTF_permit_access   (1U<<0)
  162 #define GTF_accept_transfer (2U<<0)
  163 #define GTF_transitive      (3U<<0)
  164 #define GTF_type_mask       (3U<<0)
  165 
  166 /*
  167  * Subflags for GTF_permit_access.
  168  *  GTF_readonly: Restrict @domid to read-only mappings and accesses. [GST]
  169  *  GTF_reading: Grant entry is currently mapped for reading by @domid. [XEN]
  170  *  GTF_writing: Grant entry is currently mapped for writing by @domid. [XEN]
  171  *  GTF_PAT, GTF_PWT, GTF_PCD: (x86) cache attribute flags for the grant [GST]
  172  *  GTF_sub_page: Grant access to only a subrange of the page.  @domid
  173  *                will only be allowed to copy from the grant, and not
  174  *                map it. [GST]
  175  */
  176 #define _GTF_readonly       (2)
  177 #define GTF_readonly        (1U<<_GTF_readonly)
  178 #define _GTF_reading        (3)
  179 #define GTF_reading         (1U<<_GTF_reading)
  180 #define _GTF_writing        (4)
  181 #define GTF_writing         (1U<<_GTF_writing)
  182 #define _GTF_PWT            (5)
  183 #define GTF_PWT             (1U<<_GTF_PWT)
  184 #define _GTF_PCD            (6)
  185 #define GTF_PCD             (1U<<_GTF_PCD)
  186 #define _GTF_PAT            (7)
  187 #define GTF_PAT             (1U<<_GTF_PAT)
  188 #define _GTF_sub_page       (8)
  189 #define GTF_sub_page        (1U<<_GTF_sub_page)
  190 
  191 /*
  192  * Subflags for GTF_accept_transfer:
  193  *  GTF_transfer_committed: Xen sets this flag to indicate that it is committed
  194  *      to transferring ownership of a page frame. When a guest sees this flag
  195  *      it must /not/ modify the grant entry until GTF_transfer_completed is
  196  *      set by Xen.
  197  *  GTF_transfer_completed: It is safe for the guest to spin-wait on this flag
  198  *      after reading GTF_transfer_committed. Xen will always write the frame
  199  *      address, followed by ORing this flag, in a timely manner.
  200  */
  201 #define _GTF_transfer_committed (2)
  202 #define GTF_transfer_committed  (1U<<_GTF_transfer_committed)
  203 #define _GTF_transfer_completed (3)
  204 #define GTF_transfer_completed  (1U<<_GTF_transfer_completed)
  205 
  206 /*
  207  * Version 2 grant table entries.  These fulfil the same role as
  208  * version 1 entries, but can represent more complicated operations.
  209  * Any given domain will have either a version 1 or a version 2 table,
  210  * and every entry in the table will be the same version.
  211  *
  212  * The interface by which domains use grant references does not depend
  213  * on the grant table version in use by the other domain.
  214  */
  215 #if __XEN_INTERFACE_VERSION__ >= 0x0003020a
  216 /*
  217  * Version 1 and version 2 grant entries share a common prefix.  The
  218  * fields of the prefix are documented as part of struct
  219  * grant_entry_v1.
  220  */
  221 struct grant_entry_header {
  222     uint16_t flags;
  223     domid_t  domid;
  224 };
  225 typedef struct grant_entry_header grant_entry_header_t;
  226 
  227 /*
  228  * Version 2 of the grant entry structure.
  229  */
  230 union grant_entry_v2 {
  231     grant_entry_header_t hdr;
  232 
  233     /*
  234      * This member is used for V1-style full page grants, where either:
  235      *
  236      * -- hdr.type is GTF_accept_transfer, or
  237      * -- hdr.type is GTF_permit_access and GTF_sub_page is not set.
  238      *
  239      * In that case, the frame field has the same semantics as the
  240      * field of the same name in the V1 entry structure.
  241      */
  242     struct {
  243         grant_entry_header_t hdr;
  244         uint32_t pad0;
  245         uint64_t frame;
  246     } full_page;
  247 
  248     /*
  249      * If the grant type is GTF_grant_access and GTF_sub_page is set,
  250      * @domid is allowed to access bytes [@page_off,@page_off+@length)
  251      * in frame @frame.
  252      */
  253     struct {
  254         grant_entry_header_t hdr;
  255         uint16_t page_off;
  256         uint16_t length;
  257         uint64_t frame;
  258     } sub_page;
  259 
  260     /*
  261      * If the grant is GTF_transitive, @domid is allowed to use the
  262      * grant @gref in domain @trans_domid, as if it was the local
  263      * domain.  Obviously, the transitive access must be compatible
  264      * with the original grant.
  265      *
  266      * The current version of Xen does not allow transitive grants
  267      * to be mapped.
  268      */
  269     struct {
  270         grant_entry_header_t hdr;
  271         domid_t trans_domid;
  272         uint16_t pad0;
  273         grant_ref_t gref;
  274     } transitive;
  275 
  276     uint32_t __spacer[4]; /* Pad to a power of two */
  277 };
  278 typedef union grant_entry_v2 grant_entry_v2_t;
  279 
  280 typedef uint16_t grant_status_t;
  281 
  282 #endif /* __XEN_INTERFACE_VERSION__ */
  283 
  284 /***********************************
  285  * GRANT TABLE QUERIES AND USES
  286  */
  287 
  288 /* ` enum neg_errnoval
  289  * ` HYPERVISOR_grant_table_op(enum grant_table_op cmd,
  290  * `                           void *args,
  291  * `                           unsigned int count)
  292  * `
  293  *
  294  * @args points to an array of a per-command data structure. The array
  295  * has @count members
  296  */
  297 
  298 /* ` enum grant_table_op { // GNTTABOP_* => struct gnttab_* */
  299 #define GNTTABOP_map_grant_ref        0
  300 #define GNTTABOP_unmap_grant_ref      1
  301 #define GNTTABOP_setup_table          2
  302 #define GNTTABOP_dump_table           3
  303 #define GNTTABOP_transfer             4
  304 #define GNTTABOP_copy                 5
  305 #define GNTTABOP_query_size           6
  306 #define GNTTABOP_unmap_and_replace    7
  307 #if __XEN_INTERFACE_VERSION__ >= 0x0003020a
  308 #define GNTTABOP_set_version          8
  309 #define GNTTABOP_get_status_frames    9
  310 #define GNTTABOP_get_version          10
  311 #define GNTTABOP_swap_grant_ref       11
  312 #endif /* __XEN_INTERFACE_VERSION__ */
  313 /* ` } */
  314 
  315 /*
  316  * Handle to track a mapping created via a grant reference.
  317  */
  318 typedef uint32_t grant_handle_t;
  319 
  320 /*
  321  * GNTTABOP_map_grant_ref: Map the grant entry (<dom>,<ref>) for access
  322  * by devices and/or host CPUs. If successful, <handle> is a tracking number
  323  * that must be presented later to destroy the mapping(s). On error, <handle>
  324  * is a negative status code.
  325  * NOTES:
  326  *  1. If GNTMAP_device_map is specified then <dev_bus_addr> is the address
  327  *     via which I/O devices may access the granted frame.
  328  *  2. If GNTMAP_host_map is specified then a mapping will be added at
  329  *     either a host virtual address in the current address space, or at
  330  *     a PTE at the specified machine address.  The type of mapping to
  331  *     perform is selected through the GNTMAP_contains_pte flag, and the
  332  *     address is specified in <host_addr>.
  333  *  3. Mappings should only be destroyed via GNTTABOP_unmap_grant_ref. If a
  334  *     host mapping is destroyed by other means then it is *NOT* guaranteed
  335  *     to be accounted to the correct grant reference!
  336  */
  337 struct gnttab_map_grant_ref {
  338     /* IN parameters. */
  339     uint64_t host_addr;
  340     uint32_t flags;               /* GNTMAP_* */
  341     grant_ref_t ref;
  342     domid_t  dom;
  343     /* OUT parameters. */
  344     int16_t  status;              /* => enum grant_status */
  345     grant_handle_t handle;
  346     uint64_t dev_bus_addr;
  347 };
  348 typedef struct gnttab_map_grant_ref gnttab_map_grant_ref_t;
  349 DEFINE_XEN_GUEST_HANDLE(gnttab_map_grant_ref_t);
  350 
  351 /*
  352  * GNTTABOP_unmap_grant_ref: Destroy one or more grant-reference mappings
  353  * tracked by <handle>. If <host_addr> or <dev_bus_addr> is zero, that
  354  * field is ignored. If non-zero, they must refer to a device/host mapping
  355  * that is tracked by <handle>
  356  * NOTES:
  357  *  1. The call may fail in an undefined manner if either mapping is not
  358  *     tracked by <handle>.
  359  *  3. After executing a batch of unmaps, it is guaranteed that no stale
  360  *     mappings will remain in the device or host TLBs.
  361  */
  362 struct gnttab_unmap_grant_ref {
  363     /* IN parameters. */
  364     uint64_t host_addr;
  365     uint64_t dev_bus_addr;
  366     grant_handle_t handle;
  367     /* OUT parameters. */
  368     int16_t  status;              /* => enum grant_status */
  369 };
  370 typedef struct gnttab_unmap_grant_ref gnttab_unmap_grant_ref_t;
  371 DEFINE_XEN_GUEST_HANDLE(gnttab_unmap_grant_ref_t);
  372 
  373 /*
  374  * GNTTABOP_setup_table: Set up a grant table for <dom> comprising at least
  375  * <nr_frames> pages. The frame addresses are written to the <frame_list>.
  376  * Only <nr_frames> addresses are written, even if the table is larger.
  377  * NOTES:
  378  *  1. <dom> may be specified as DOMID_SELF.
  379  *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
  380  *  3. Xen may not support more than a single grant-table page per domain.
  381  */
  382 struct gnttab_setup_table {
  383     /* IN parameters. */
  384     domid_t  dom;
  385     uint32_t nr_frames;
  386     /* OUT parameters. */
  387     int16_t  status;              /* => enum grant_status */
  388     XEN_GUEST_HANDLE(ulong) frame_list;
  389 };
  390 typedef struct gnttab_setup_table gnttab_setup_table_t;
  391 DEFINE_XEN_GUEST_HANDLE(gnttab_setup_table_t);
  392 
  393 /*
  394  * GNTTABOP_dump_table: Dump the contents of the grant table to the
  395  * xen console. Debugging use only.
  396  */
  397 struct gnttab_dump_table {
  398     /* IN parameters. */
  399     domid_t dom;
  400     /* OUT parameters. */
  401     int16_t status;               /* => enum grant_status */
  402 };
  403 typedef struct gnttab_dump_table gnttab_dump_table_t;
  404 DEFINE_XEN_GUEST_HANDLE(gnttab_dump_table_t);
  405 
  406 /*
  407  * GNTTABOP_transfer_grant_ref: Transfer <frame> to a foreign domain. The
  408  * foreign domain has previously registered its interest in the transfer via
  409  * <domid, ref>.
  410  *
  411  * Note that, even if the transfer fails, the specified page no longer belongs
  412  * to the calling domain *unless* the error is GNTST_bad_page.
  413  */
  414 struct gnttab_transfer {
  415     /* IN parameters. */
  416     xen_pfn_t     mfn;
  417     domid_t       domid;
  418     grant_ref_t   ref;
  419     /* OUT parameters. */
  420     int16_t       status;
  421 };
  422 typedef struct gnttab_transfer gnttab_transfer_t;
  423 DEFINE_XEN_GUEST_HANDLE(gnttab_transfer_t);
  424 
  425 
  426 /*
  427  * GNTTABOP_copy: Hypervisor based copy
  428  * source and destinations can be eithers MFNs or, for foreign domains,
  429  * grant references. the foreign domain has to grant read/write access
  430  * in its grant table.
  431  *
  432  * The flags specify what type source and destinations are (either MFN
  433  * or grant reference).
  434  *
  435  * Note that this can also be used to copy data between two domains
  436  * via a third party if the source and destination domains had previously
  437  * grant appropriate access to their pages to the third party.
  438  *
  439  * source_offset specifies an offset in the source frame, dest_offset
  440  * the offset in the target frame and  len specifies the number of
  441  * bytes to be copied.
  442  */
  443 
  444 #define _GNTCOPY_source_gref      (0)
  445 #define GNTCOPY_source_gref       (1<<_GNTCOPY_source_gref)
  446 #define _GNTCOPY_dest_gref        (1)
  447 #define GNTCOPY_dest_gref         (1<<_GNTCOPY_dest_gref)
  448 #define _GNTCOPY_can_fail         (2)
  449 #define GNTCOPY_can_fail          (1<<_GNTCOPY_can_fail)
  450 
  451 struct gnttab_copy {
  452     /* IN parameters. */
  453     struct {
  454         union {
  455             grant_ref_t ref;
  456             xen_pfn_t   gmfn;
  457         } u;
  458         domid_t  domid;
  459         uint16_t offset;
  460     } source, dest;
  461     uint16_t      len;
  462     uint16_t      flags;          /* GNTCOPY_* */
  463     /* OUT parameters. */
  464     int16_t       status;
  465 };
  466 typedef struct gnttab_copy  gnttab_copy_t;
  467 DEFINE_XEN_GUEST_HANDLE(gnttab_copy_t);
  468 
  469 /*
  470  * GNTTABOP_query_size: Query the current and maximum sizes of the shared
  471  * grant table.
  472  * NOTES:
  473  *  1. <dom> may be specified as DOMID_SELF.
  474  *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
  475  */
  476 struct gnttab_query_size {
  477     /* IN parameters. */
  478     domid_t  dom;
  479     /* OUT parameters. */
  480     uint32_t nr_frames;
  481     uint32_t max_nr_frames;
  482     int16_t  status;              /* => enum grant_status */
  483 };
  484 typedef struct gnttab_query_size gnttab_query_size_t;
  485 DEFINE_XEN_GUEST_HANDLE(gnttab_query_size_t);
  486 
  487 /*
  488  * GNTTABOP_unmap_and_replace: Destroy one or more grant-reference mappings
  489  * tracked by <handle> but atomically replace the page table entry with one
  490  * pointing to the machine address under <new_addr>.  <new_addr> will be
  491  * redirected to the null entry.
  492  * NOTES:
  493  *  1. The call may fail in an undefined manner if either mapping is not
  494  *     tracked by <handle>.
  495  *  2. After executing a batch of unmaps, it is guaranteed that no stale
  496  *     mappings will remain in the device or host TLBs.
  497  */
  498 struct gnttab_unmap_and_replace {
  499     /* IN parameters. */
  500     uint64_t host_addr;
  501     uint64_t new_addr;
  502     grant_handle_t handle;
  503     /* OUT parameters. */
  504     int16_t  status;              /* => enum grant_status */
  505 };
  506 typedef struct gnttab_unmap_and_replace gnttab_unmap_and_replace_t;
  507 DEFINE_XEN_GUEST_HANDLE(gnttab_unmap_and_replace_t);
  508 
  509 #if __XEN_INTERFACE_VERSION__ >= 0x0003020a
  510 /*
  511  * GNTTABOP_set_version: Request a particular version of the grant
  512  * table shared table structure.  This operation can only be performed
  513  * once in any given domain.  It must be performed before any grants
  514  * are activated; otherwise, the domain will be stuck with version 1.
  515  * The only defined versions are 1 and 2.
  516  */
  517 struct gnttab_set_version {
  518     /* IN/OUT parameters */
  519     uint32_t version;
  520 };
  521 typedef struct gnttab_set_version gnttab_set_version_t;
  522 DEFINE_XEN_GUEST_HANDLE(gnttab_set_version_t);
  523 
  524 
  525 /*
  526  * GNTTABOP_get_status_frames: Get the list of frames used to store grant
  527  * status for <dom>. In grant format version 2, the status is separated
  528  * from the other shared grant fields to allow more efficient synchronization
  529  * using barriers instead of atomic cmpexch operations.
  530  * <nr_frames> specify the size of vector <frame_list>.
  531  * The frame addresses are returned in the <frame_list>.
  532  * Only <nr_frames> addresses are returned, even if the table is larger.
  533  * NOTES:
  534  *  1. <dom> may be specified as DOMID_SELF.
  535  *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
  536  */
  537 struct gnttab_get_status_frames {
  538     /* IN parameters. */
  539     uint32_t nr_frames;
  540     domid_t  dom;
  541     /* OUT parameters. */
  542     int16_t  status;              /* => enum grant_status */
  543     XEN_GUEST_HANDLE(uint64_t) frame_list;
  544 };
  545 typedef struct gnttab_get_status_frames gnttab_get_status_frames_t;
  546 DEFINE_XEN_GUEST_HANDLE(gnttab_get_status_frames_t);
  547 
  548 /*
  549  * GNTTABOP_get_version: Get the grant table version which is in
  550  * effect for domain <dom>.
  551  */
  552 struct gnttab_get_version {
  553     /* IN parameters */
  554     domid_t dom;
  555     uint16_t pad;
  556     /* OUT parameters */
  557     uint32_t version;
  558 };
  559 typedef struct gnttab_get_version gnttab_get_version_t;
  560 DEFINE_XEN_GUEST_HANDLE(gnttab_get_version_t);
  561 
  562 /*
  563  * GNTTABOP_swap_grant_ref: Swap the contents of two grant entries.
  564  */
  565 struct gnttab_swap_grant_ref {
  566     /* IN parameters */
  567     grant_ref_t ref_a;
  568     grant_ref_t ref_b;
  569     /* OUT parameters */
  570     int16_t status;             /* => enum grant_status */
  571 };
  572 typedef struct gnttab_swap_grant_ref gnttab_swap_grant_ref_t;
  573 DEFINE_XEN_GUEST_HANDLE(gnttab_swap_grant_ref_t);
  574 
  575 #endif /* __XEN_INTERFACE_VERSION__ */
  576 
  577 /*
  578  * Bitfield values for gnttab_map_grant_ref.flags.
  579  */
  580  /* Map the grant entry for access by I/O devices. */
  581 #define _GNTMAP_device_map      (0)
  582 #define GNTMAP_device_map       (1<<_GNTMAP_device_map)
  583  /* Map the grant entry for access by host CPUs. */
  584 #define _GNTMAP_host_map        (1)
  585 #define GNTMAP_host_map         (1<<_GNTMAP_host_map)
  586  /* Accesses to the granted frame will be restricted to read-only access. */
  587 #define _GNTMAP_readonly        (2)
  588 #define GNTMAP_readonly         (1<<_GNTMAP_readonly)
  589  /*
  590   * GNTMAP_host_map subflag:
  591   *  0 => The host mapping is usable only by the guest OS.
  592   *  1 => The host mapping is usable by guest OS + current application.
  593   */
  594 #define _GNTMAP_application_map (3)
  595 #define GNTMAP_application_map  (1<<_GNTMAP_application_map)
  596 
  597  /*
  598   * GNTMAP_contains_pte subflag:
  599   *  0 => This map request contains a host virtual address.
  600   *  1 => This map request contains the machine addess of the PTE to update.
  601   */
  602 #define _GNTMAP_contains_pte    (4)
  603 #define GNTMAP_contains_pte     (1<<_GNTMAP_contains_pte)
  604 
  605 #define _GNTMAP_can_fail        (5)
  606 #define GNTMAP_can_fail         (1<<_GNTMAP_can_fail)
  607 
  608 /*
  609  * Bits to be placed in guest kernel available PTE bits (architecture
  610  * dependent; only supported when XENFEAT_gnttab_map_avail_bits is set).
  611  */
  612 #define _GNTMAP_guest_avail0    (16)
  613 #define GNTMAP_guest_avail_mask ((uint32_t)~0 << _GNTMAP_guest_avail0)
  614 
  615 /*
  616  * Values for error status returns. All errors are -ve.
  617  */
  618 /* ` enum grant_status { */
  619 #define GNTST_okay             (0)  /* Normal return.                        */
  620 #define GNTST_general_error    (-1) /* General undefined error.              */
  621 #define GNTST_bad_domain       (-2) /* Unrecognsed domain id.                */
  622 #define GNTST_bad_gntref       (-3) /* Unrecognised or inappropriate gntref. */
  623 #define GNTST_bad_handle       (-4) /* Unrecognised or inappropriate handle. */
  624 #define GNTST_bad_virt_addr    (-5) /* Inappropriate virtual address to map. */
  625 #define GNTST_bad_dev_addr     (-6) /* Inappropriate device address to unmap.*/
  626 #define GNTST_no_device_space  (-7) /* Out of space in I/O MMU.              */
  627 #define GNTST_permission_denied (-8) /* Not enough privilege for operation.  */
  628 #define GNTST_bad_page         (-9) /* Specified page was invalid for op.    */
  629 #define GNTST_bad_copy_arg    (-10) /* copy arguments cross page boundary.   */
  630 #define GNTST_address_too_big (-11) /* transfer page address too large.      */
  631 #define GNTST_eagain          (-12) /* Operation not done; try again.        */
  632 /* ` } */
  633 
  634 #define GNTTABOP_error_msgs {                   \
  635     "okay",                                     \
  636     "undefined error",                          \
  637     "unrecognised domain id",                   \
  638     "invalid grant reference",                  \
  639     "invalid mapping handle",                   \
  640     "invalid virtual address",                  \
  641     "invalid device address",                   \
  642     "no spare translation slot in the I/O MMU", \
  643     "permission denied",                        \
  644     "bad page",                                 \
  645     "copy arguments cross page boundary",       \
  646     "page address size too large",              \
  647     "operation not done; try again"             \
  648 }
  649 
  650 #endif /* __XEN_PUBLIC_GRANT_TABLE_H__ */
  651 
  652 /*
  653  * Local variables:
  654  * mode: C
  655  * c-set-style: "BSD"
  656  * c-basic-offset: 4
  657  * tab-width: 4
  658  * indent-tabs-mode: nil
  659  * End:
  660  */

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