The Design and Implementation of the FreeBSD Operating System, Second Edition
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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: GFN that @domid is allowed to map and access. [GST]
  138      * GTF_accept_transfer: GFN that @domid is allowed to transfer into. [GST]
  139      * GTF_transfer_completed: MFN whose ownership transferred by @domid
  140      *                         (non-translated guests only). [XEN]
  141      */
  142     uint32_t frame;
  143 };
  144 typedef struct grant_entry_v1 grant_entry_v1_t;
  145 
  146 /* The first few grant table entries will be preserved across grant table
  147  * version changes and may be pre-populated at domain creation by tools.
  148  */
  149 #define GNTTAB_NR_RESERVED_ENTRIES     8
  150 #define GNTTAB_RESERVED_CONSOLE        0
  151 #define GNTTAB_RESERVED_XENSTORE       1
  152 
  153 /*
  154  * Type of grant entry.
  155  *  GTF_invalid: This grant entry grants no privileges.
  156  *  GTF_permit_access: Allow @domid to map/access @frame.
  157  *  GTF_accept_transfer: Allow @domid to transfer ownership of one page frame
  158  *                       to this guest. Xen writes the page number to @frame.
  159  *  GTF_transitive: Allow @domid to transitively access a subrange of
  160  *                  @trans_grant in @trans_domid.  No mappings are allowed.
  161  */
  162 #define GTF_invalid         (0U<<0)
  163 #define GTF_permit_access   (1U<<0)
  164 #define GTF_accept_transfer (2U<<0)
  165 #define GTF_transitive      (3U<<0)
  166 #define GTF_type_mask       (3U<<0)
  167 
  168 /*
  169  * Subflags for GTF_permit_access.
  170  *  GTF_readonly: Restrict @domid to read-only mappings and accesses. [GST]
  171  *  GTF_reading: Grant entry is currently mapped for reading by @domid. [XEN]
  172  *  GTF_writing: Grant entry is currently mapped for writing by @domid. [XEN]
  173  *  GTF_PAT, GTF_PWT, GTF_PCD: (x86) cache attribute flags for the grant [GST]
  174  *  GTF_sub_page: Grant access to only a subrange of the page.  @domid
  175  *                will only be allowed to copy from the grant, and not
  176  *                map it. [GST]
  177  */
  178 #define _GTF_readonly       (2)
  179 #define GTF_readonly        (1U<<_GTF_readonly)
  180 #define _GTF_reading        (3)
  181 #define GTF_reading         (1U<<_GTF_reading)
  182 #define _GTF_writing        (4)
  183 #define GTF_writing         (1U<<_GTF_writing)
  184 #define _GTF_PWT            (5)
  185 #define GTF_PWT             (1U<<_GTF_PWT)
  186 #define _GTF_PCD            (6)
  187 #define GTF_PCD             (1U<<_GTF_PCD)
  188 #define _GTF_PAT            (7)
  189 #define GTF_PAT             (1U<<_GTF_PAT)
  190 #define _GTF_sub_page       (8)
  191 #define GTF_sub_page        (1U<<_GTF_sub_page)
  192 
  193 /*
  194  * Subflags for GTF_accept_transfer:
  195  *  GTF_transfer_committed: Xen sets this flag to indicate that it is committed
  196  *      to transferring ownership of a page frame. When a guest sees this flag
  197  *      it must /not/ modify the grant entry until GTF_transfer_completed is
  198  *      set by Xen.
  199  *  GTF_transfer_completed: It is safe for the guest to spin-wait on this flag
  200  *      after reading GTF_transfer_committed. Xen will always write the frame
  201  *      address, followed by ORing this flag, in a timely manner.
  202  */
  203 #define _GTF_transfer_committed (2)
  204 #define GTF_transfer_committed  (1U<<_GTF_transfer_committed)
  205 #define _GTF_transfer_completed (3)
  206 #define GTF_transfer_completed  (1U<<_GTF_transfer_completed)
  207 
  208 /*
  209  * Version 2 grant table entries.  These fulfil the same role as
  210  * version 1 entries, but can represent more complicated operations.
  211  * Any given domain will have either a version 1 or a version 2 table,
  212  * and every entry in the table will be the same version.
  213  *
  214  * The interface by which domains use grant references does not depend
  215  * on the grant table version in use by the other domain.
  216  */
  217 #if __XEN_INTERFACE_VERSION__ >= 0x0003020a
  218 /*
  219  * Version 1 and version 2 grant entries share a common prefix.  The
  220  * fields of the prefix are documented as part of struct
  221  * grant_entry_v1.
  222  */
  223 struct grant_entry_header {
  224     uint16_t flags;
  225     domid_t  domid;
  226 };
  227 typedef struct grant_entry_header grant_entry_header_t;
  228 
  229 /*
  230  * Version 2 of the grant entry structure.
  231  */
  232 union grant_entry_v2 {
  233     grant_entry_header_t hdr;
  234 
  235     /*
  236      * This member is used for V1-style full page grants, where either:
  237      *
  238      * -- hdr.type is GTF_accept_transfer, or
  239      * -- hdr.type is GTF_permit_access and GTF_sub_page is not set.
  240      *
  241      * In that case, the frame field has the same semantics as the
  242      * field of the same name in the V1 entry structure.
  243      */
  244     struct {
  245         grant_entry_header_t hdr;
  246         uint32_t pad0;
  247         uint64_t frame;
  248     } full_page;
  249 
  250     /*
  251      * If the grant type is GTF_grant_access and GTF_sub_page is set,
  252      * @domid is allowed to access bytes [@page_off,@page_off+@length)
  253      * in frame @frame.
  254      */
  255     struct {
  256         grant_entry_header_t hdr;
  257         uint16_t page_off;
  258         uint16_t length;
  259         uint64_t frame;
  260     } sub_page;
  261 
  262     /*
  263      * If the grant is GTF_transitive, @domid is allowed to use the
  264      * grant @gref in domain @trans_domid, as if it was the local
  265      * domain.  Obviously, the transitive access must be compatible
  266      * with the original grant.
  267      *
  268      * The current version of Xen does not allow transitive grants
  269      * to be mapped.
  270      */
  271     struct {
  272         grant_entry_header_t hdr;
  273         domid_t trans_domid;
  274         uint16_t pad0;
  275         grant_ref_t gref;
  276     } transitive;
  277 
  278     uint32_t __spacer[4]; /* Pad to a power of two */
  279 };
  280 typedef union grant_entry_v2 grant_entry_v2_t;
  281 
  282 typedef uint16_t grant_status_t;
  283 
  284 #endif /* __XEN_INTERFACE_VERSION__ */
  285 
  286 /***********************************
  287  * GRANT TABLE QUERIES AND USES
  288  */
  289 
  290 /* ` enum neg_errnoval
  291  * ` HYPERVISOR_grant_table_op(enum grant_table_op cmd,
  292  * `                           void *args,
  293  * `                           unsigned int count)
  294  * `
  295  *
  296  * @args points to an array of a per-command data structure. The array
  297  * has @count members
  298  */
  299 
  300 /* ` enum grant_table_op { // GNTTABOP_* => struct gnttab_* */
  301 #define GNTTABOP_map_grant_ref        0
  302 #define GNTTABOP_unmap_grant_ref      1
  303 #define GNTTABOP_setup_table          2
  304 #define GNTTABOP_dump_table           3
  305 #define GNTTABOP_transfer             4
  306 #define GNTTABOP_copy                 5
  307 #define GNTTABOP_query_size           6
  308 #define GNTTABOP_unmap_and_replace    7
  309 #if __XEN_INTERFACE_VERSION__ >= 0x0003020a
  310 #define GNTTABOP_set_version          8
  311 #define GNTTABOP_get_status_frames    9
  312 #define GNTTABOP_get_version          10
  313 #define GNTTABOP_swap_grant_ref       11
  314 #define GNTTABOP_cache_flush          12
  315 #endif /* __XEN_INTERFACE_VERSION__ */
  316 /* ` } */
  317 
  318 /*
  319  * Handle to track a mapping created via a grant reference.
  320  */
  321 typedef uint32_t grant_handle_t;
  322 
  323 /*
  324  * GNTTABOP_map_grant_ref: Map the grant entry (<dom>,<ref>) for access
  325  * by devices and/or host CPUs. If successful, <handle> is a tracking number
  326  * that must be presented later to destroy the mapping(s). On error, <status>
  327  * is a negative status code.
  328  * NOTES:
  329  *  1. If GNTMAP_device_map is specified then <dev_bus_addr> is the address
  330  *     via which I/O devices may access the granted frame.
  331  *  2. If GNTMAP_host_map is specified then a mapping will be added at
  332  *     either a host virtual address in the current address space, or at
  333  *     a PTE at the specified machine address.  The type of mapping to
  334  *     perform is selected through the GNTMAP_contains_pte flag, and the
  335  *     address is specified in <host_addr>.
  336  *  3. Mappings should only be destroyed via GNTTABOP_unmap_grant_ref. If a
  337  *     host mapping is destroyed by other means then it is *NOT* guaranteed
  338  *     to be accounted to the correct grant reference!
  339  */
  340 struct gnttab_map_grant_ref {
  341     /* IN parameters. */
  342     uint64_t host_addr;
  343     uint32_t flags;               /* GNTMAP_* */
  344     grant_ref_t ref;
  345     domid_t  dom;
  346     /* OUT parameters. */
  347     int16_t  status;              /* => enum grant_status */
  348     grant_handle_t handle;
  349     uint64_t dev_bus_addr;
  350 };
  351 typedef struct gnttab_map_grant_ref gnttab_map_grant_ref_t;
  352 DEFINE_XEN_GUEST_HANDLE(gnttab_map_grant_ref_t);
  353 
  354 /*
  355  * GNTTABOP_unmap_grant_ref: Destroy one or more grant-reference mappings
  356  * tracked by <handle>. If <host_addr> or <dev_bus_addr> is zero, that
  357  * field is ignored. If non-zero, they must refer to a device/host mapping
  358  * that is tracked by <handle>
  359  * NOTES:
  360  *  1. The call may fail in an undefined manner if either mapping is not
  361  *     tracked by <handle>.
  362  *  3. After executing a batch of unmaps, it is guaranteed that no stale
  363  *     mappings will remain in the device or host TLBs.
  364  */
  365 struct gnttab_unmap_grant_ref {
  366     /* IN parameters. */
  367     uint64_t host_addr;
  368     uint64_t dev_bus_addr;
  369     grant_handle_t handle;
  370     /* OUT parameters. */
  371     int16_t  status;              /* => enum grant_status */
  372 };
  373 typedef struct gnttab_unmap_grant_ref gnttab_unmap_grant_ref_t;
  374 DEFINE_XEN_GUEST_HANDLE(gnttab_unmap_grant_ref_t);
  375 
  376 /*
  377  * GNTTABOP_setup_table: Set up a grant table for <dom> comprising at least
  378  * <nr_frames> pages. The frame addresses are written to the <frame_list>.
  379  * Only <nr_frames> addresses are written, even if the table is larger.
  380  * NOTES:
  381  *  1. <dom> may be specified as DOMID_SELF.
  382  *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
  383  *  3. Xen may not support more than a single grant-table page per domain.
  384  */
  385 struct gnttab_setup_table {
  386     /* IN parameters. */
  387     domid_t  dom;
  388     uint32_t nr_frames;
  389     /* OUT parameters. */
  390     int16_t  status;              /* => enum grant_status */
  391 #if __XEN_INTERFACE_VERSION__ < 0x00040300
  392     XEN_GUEST_HANDLE(ulong) frame_list;
  393 #else
  394     XEN_GUEST_HANDLE(xen_pfn_t) frame_list;
  395 #endif
  396 };
  397 typedef struct gnttab_setup_table gnttab_setup_table_t;
  398 DEFINE_XEN_GUEST_HANDLE(gnttab_setup_table_t);
  399 
  400 /*
  401  * GNTTABOP_dump_table: Dump the contents of the grant table to the
  402  * xen console. Debugging use only.
  403  */
  404 struct gnttab_dump_table {
  405     /* IN parameters. */
  406     domid_t dom;
  407     /* OUT parameters. */
  408     int16_t status;               /* => enum grant_status */
  409 };
  410 typedef struct gnttab_dump_table gnttab_dump_table_t;
  411 DEFINE_XEN_GUEST_HANDLE(gnttab_dump_table_t);
  412 
  413 /*
  414  * GNTTABOP_transfer_grant_ref: Transfer <frame> to a foreign domain. The
  415  * foreign domain has previously registered its interest in the transfer via
  416  * <domid, ref>.
  417  *
  418  * Note that, even if the transfer fails, the specified page no longer belongs
  419  * to the calling domain *unless* the error is GNTST_bad_page.
  420  */
  421 struct gnttab_transfer {
  422     /* IN parameters. */
  423     xen_pfn_t     mfn;
  424     domid_t       domid;
  425     grant_ref_t   ref;
  426     /* OUT parameters. */
  427     int16_t       status;
  428 };
  429 typedef struct gnttab_transfer gnttab_transfer_t;
  430 DEFINE_XEN_GUEST_HANDLE(gnttab_transfer_t);
  431 
  432 
  433 /*
  434  * GNTTABOP_copy: Hypervisor based copy
  435  * source and destinations can be eithers MFNs or, for foreign domains,
  436  * grant references. the foreign domain has to grant read/write access
  437  * in its grant table.
  438  *
  439  * The flags specify what type source and destinations are (either MFN
  440  * or grant reference).
  441  *
  442  * Note that this can also be used to copy data between two domains
  443  * via a third party if the source and destination domains had previously
  444  * grant appropriate access to their pages to the third party.
  445  *
  446  * source_offset specifies an offset in the source frame, dest_offset
  447  * the offset in the target frame and  len specifies the number of
  448  * bytes to be copied.
  449  */
  450 
  451 #define _GNTCOPY_source_gref      (0)
  452 #define GNTCOPY_source_gref       (1<<_GNTCOPY_source_gref)
  453 #define _GNTCOPY_dest_gref        (1)
  454 #define GNTCOPY_dest_gref         (1<<_GNTCOPY_dest_gref)
  455 
  456 struct gnttab_copy {
  457     /* IN parameters. */
  458     struct gnttab_copy_ptr {
  459         union {
  460             grant_ref_t ref;
  461             xen_pfn_t   gmfn;
  462         } u;
  463         domid_t  domid;
  464         uint16_t offset;
  465     } source, dest;
  466     uint16_t      len;
  467     uint16_t      flags;          /* GNTCOPY_* */
  468     /* OUT parameters. */
  469     int16_t       status;
  470 };
  471 typedef struct gnttab_copy  gnttab_copy_t;
  472 DEFINE_XEN_GUEST_HANDLE(gnttab_copy_t);
  473 
  474 /*
  475  * GNTTABOP_query_size: Query the current and maximum sizes of the shared
  476  * grant table.
  477  * NOTES:
  478  *  1. <dom> may be specified as DOMID_SELF.
  479  *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
  480  */
  481 struct gnttab_query_size {
  482     /* IN parameters. */
  483     domid_t  dom;
  484     /* OUT parameters. */
  485     uint32_t nr_frames;
  486     uint32_t max_nr_frames;
  487     int16_t  status;              /* => enum grant_status */
  488 };
  489 typedef struct gnttab_query_size gnttab_query_size_t;
  490 DEFINE_XEN_GUEST_HANDLE(gnttab_query_size_t);
  491 
  492 /*
  493  * GNTTABOP_unmap_and_replace: Destroy one or more grant-reference mappings
  494  * tracked by <handle> but atomically replace the page table entry with one
  495  * pointing to the machine address under <new_addr>.  <new_addr> will be
  496  * redirected to the null entry.
  497  * NOTES:
  498  *  1. The call may fail in an undefined manner if either mapping is not
  499  *     tracked by <handle>.
  500  *  2. After executing a batch of unmaps, it is guaranteed that no stale
  501  *     mappings will remain in the device or host TLBs.
  502  */
  503 struct gnttab_unmap_and_replace {
  504     /* IN parameters. */
  505     uint64_t host_addr;
  506     uint64_t new_addr;
  507     grant_handle_t handle;
  508     /* OUT parameters. */
  509     int16_t  status;              /* => enum grant_status */
  510 };
  511 typedef struct gnttab_unmap_and_replace gnttab_unmap_and_replace_t;
  512 DEFINE_XEN_GUEST_HANDLE(gnttab_unmap_and_replace_t);
  513 
  514 #if __XEN_INTERFACE_VERSION__ >= 0x0003020a
  515 /*
  516  * GNTTABOP_set_version: Request a particular version of the grant
  517  * table shared table structure.  This operation can only be performed
  518  * once in any given domain.  It must be performed before any grants
  519  * are activated; otherwise, the domain will be stuck with version 1.
  520  * The only defined versions are 1 and 2.
  521  */
  522 struct gnttab_set_version {
  523     /* IN/OUT parameters */
  524     uint32_t version;
  525 };
  526 typedef struct gnttab_set_version gnttab_set_version_t;
  527 DEFINE_XEN_GUEST_HANDLE(gnttab_set_version_t);
  528 
  529 
  530 /*
  531  * GNTTABOP_get_status_frames: Get the list of frames used to store grant
  532  * status for <dom>. In grant format version 2, the status is separated
  533  * from the other shared grant fields to allow more efficient synchronization
  534  * using barriers instead of atomic cmpexch operations.
  535  * <nr_frames> specify the size of vector <frame_list>.
  536  * The frame addresses are returned in the <frame_list>.
  537  * Only <nr_frames> addresses are returned, even if the table is larger.
  538  * NOTES:
  539  *  1. <dom> may be specified as DOMID_SELF.
  540  *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
  541  */
  542 struct gnttab_get_status_frames {
  543     /* IN parameters. */
  544     uint32_t nr_frames;
  545     domid_t  dom;
  546     /* OUT parameters. */
  547     int16_t  status;              /* => enum grant_status */
  548     XEN_GUEST_HANDLE(uint64_t) frame_list;
  549 };
  550 typedef struct gnttab_get_status_frames gnttab_get_status_frames_t;
  551 DEFINE_XEN_GUEST_HANDLE(gnttab_get_status_frames_t);
  552 
  553 /*
  554  * GNTTABOP_get_version: Get the grant table version which is in
  555  * effect for domain <dom>.
  556  */
  557 struct gnttab_get_version {
  558     /* IN parameters */
  559     domid_t dom;
  560     uint16_t pad;
  561     /* OUT parameters */
  562     uint32_t version;
  563 };
  564 typedef struct gnttab_get_version gnttab_get_version_t;
  565 DEFINE_XEN_GUEST_HANDLE(gnttab_get_version_t);
  566 
  567 /*
  568  * GNTTABOP_swap_grant_ref: Swap the contents of two grant entries.
  569  */
  570 struct gnttab_swap_grant_ref {
  571     /* IN parameters */
  572     grant_ref_t ref_a;
  573     grant_ref_t ref_b;
  574     /* OUT parameters */
  575     int16_t status;             /* => enum grant_status */
  576 };
  577 typedef struct gnttab_swap_grant_ref gnttab_swap_grant_ref_t;
  578 DEFINE_XEN_GUEST_HANDLE(gnttab_swap_grant_ref_t);
  579 
  580 /*
  581  * Issue one or more cache maintenance operations on a portion of a
  582  * page granted to the calling domain by a foreign domain.
  583  */
  584 struct gnttab_cache_flush {
  585     union {
  586         uint64_t dev_bus_addr;
  587         grant_ref_t ref;
  588     } a;
  589     uint16_t offset; /* offset from start of grant */
  590     uint16_t length; /* size within the grant */
  591 #define GNTTAB_CACHE_CLEAN          (1<<0)
  592 #define GNTTAB_CACHE_INVAL          (1<<1)
  593 #define GNTTAB_CACHE_SOURCE_GREF    (1<<31)
  594     uint32_t op;
  595 };
  596 typedef struct gnttab_cache_flush gnttab_cache_flush_t;
  597 DEFINE_XEN_GUEST_HANDLE(gnttab_cache_flush_t);
  598 
  599 #endif /* __XEN_INTERFACE_VERSION__ */
  600 
  601 /*
  602  * Bitfield values for gnttab_map_grant_ref.flags.
  603  */
  604  /* Map the grant entry for access by I/O devices. */
  605 #define _GNTMAP_device_map      (0)
  606 #define GNTMAP_device_map       (1<<_GNTMAP_device_map)
  607  /* Map the grant entry for access by host CPUs. */
  608 #define _GNTMAP_host_map        (1)
  609 #define GNTMAP_host_map         (1<<_GNTMAP_host_map)
  610  /* Accesses to the granted frame will be restricted to read-only access. */
  611 #define _GNTMAP_readonly        (2)
  612 #define GNTMAP_readonly         (1<<_GNTMAP_readonly)
  613  /*
  614   * GNTMAP_host_map subflag:
  615   *  0 => The host mapping is usable only by the guest OS.
  616   *  1 => The host mapping is usable by guest OS + current application.
  617   */
  618 #define _GNTMAP_application_map (3)
  619 #define GNTMAP_application_map  (1<<_GNTMAP_application_map)
  620 
  621  /*
  622   * GNTMAP_contains_pte subflag:
  623   *  0 => This map request contains a host virtual address.
  624   *  1 => This map request contains the machine addess of the PTE to update.
  625   */
  626 #define _GNTMAP_contains_pte    (4)
  627 #define GNTMAP_contains_pte     (1<<_GNTMAP_contains_pte)
  628 
  629 #define _GNTMAP_can_fail        (5)
  630 #define GNTMAP_can_fail         (1<<_GNTMAP_can_fail)
  631 
  632 /*
  633  * Bits to be placed in guest kernel available PTE bits (architecture
  634  * dependent; only supported when XENFEAT_gnttab_map_avail_bits is set).
  635  */
  636 #define _GNTMAP_guest_avail0    (16)
  637 #define GNTMAP_guest_avail_mask ((uint32_t)~0 << _GNTMAP_guest_avail0)
  638 
  639 /*
  640  * Values for error status returns. All errors are -ve.
  641  */
  642 /* ` enum grant_status { */
  643 #define GNTST_okay             (0)  /* Normal return.                        */
  644 #define GNTST_general_error    (-1) /* General undefined error.              */
  645 #define GNTST_bad_domain       (-2) /* Unrecognsed domain id.                */
  646 #define GNTST_bad_gntref       (-3) /* Unrecognised or inappropriate gntref. */
  647 #define GNTST_bad_handle       (-4) /* Unrecognised or inappropriate handle. */
  648 #define GNTST_bad_virt_addr    (-5) /* Inappropriate virtual address to map. */
  649 #define GNTST_bad_dev_addr     (-6) /* Inappropriate device address to unmap.*/
  650 #define GNTST_no_device_space  (-7) /* Out of space in I/O MMU.              */
  651 #define GNTST_permission_denied (-8) /* Not enough privilege for operation.  */
  652 #define GNTST_bad_page         (-9) /* Specified page was invalid for op.    */
  653 #define GNTST_bad_copy_arg    (-10) /* copy arguments cross page boundary.   */
  654 #define GNTST_address_too_big (-11) /* transfer page address too large.      */
  655 #define GNTST_eagain          (-12) /* Operation not done; try again.        */
  656 /* ` } */
  657 
  658 #define GNTTABOP_error_msgs {                   \
  659     "okay",                                     \
  660     "undefined error",                          \
  661     "unrecognised domain id",                   \
  662     "invalid grant reference",                  \
  663     "invalid mapping handle",                   \
  664     "invalid virtual address",                  \
  665     "invalid device address",                   \
  666     "no spare translation slot in the I/O MMU", \
  667     "permission denied",                        \
  668     "bad page",                                 \
  669     "copy arguments cross page boundary",       \
  670     "page address size too large",              \
  671     "operation not done; try again"             \
  672 }
  673 
  674 #endif /* __XEN_PUBLIC_GRANT_TABLE_H__ */
  675 
  676 /*
  677  * Local variables:
  678  * mode: C
  679  * c-file-style: "BSD"
  680  * c-basic-offset: 4
  681  * tab-width: 4
  682  * indent-tabs-mode: nil
  683  * End:
  684  */

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