/****************************************************************************** * grant_table.h * * Interface for granting foreign access to page frames, and receiving * page-ownership transfers. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to * deal in the Software without restriction, including without limitation the * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or * sell copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. * * Copyright (c) 2004, K A Fraser */ #ifndef __XEN_PUBLIC_GRANT_TABLE_H__#define __XEN_PUBLIC_GRANT_TABLE_H__ #include <xen/interface/xen.h> /*********************************** * GRANT TABLE REPRESENTATION */ /* Some rough guidelines on accessing and updating grant-table entries * in a concurrency-safe manner. For more information, Linux contains a * reference implementation for guest OSes (arch/xen/kernel/grant_table.c). * * NB. WMB is a no-op on current-generation x86 processors. However, a *     compiler barrier will still be required. * * Introducing a valid entry into the grant table: *  1. Write ent->domid. *  2. Write ent->frame: *      GTF_permit_access:   Frame to which access is permitted. *      GTF_accept_transfer: Pseudo-phys frame slot being filled by new *                           frame, or zero if none. *  3. Write memory barrier (WMB). *  4. Write ent->flags, inc. valid type. * * Invalidating an unused GTF_permit_access entry: *  1. flags = ent->flags. *  2. Observe that !(flags & (GTF_reading|GTF_writing)). *  3. Check result of SMP-safe CMPXCHG(&ent->flags, flags, 0). *  NB. No need for WMB as reuse of entry is control-dependent on success of *      step 3, and all architectures guarantee ordering of ctrl-dep writes. * * Invalidating an in-use GTF_permit_access entry: *  This cannot be done directly. Request assistance from the domain controller *  which can set a timeout on the use of a grant entry and take necessary *  action. (NB. This is not yet implemented!). * * Invalidating an unused GTF_accept_transfer entry: *  1. flags = ent->flags. *  2. Observe that !(flags & GTF_transfer_committed). [*] *  3. Check result of SMP-safe CMPXCHG(&ent->flags, flags, 0). *  NB. No need for WMB as reuse of entry is control-dependent on success of *      step 3, and all architectures guarantee ordering of ctrl-dep writes. *  [*] If GTF_transfer_committed is set then the grant entry is 'committed'. *      The guest must /not/ modify the grant entry until the address of the *      transferred frame is written. It is safe for the guest to spin waiting *      for this to occur (detect by observing GTF_transfer_completed in *      ent->flags). * * Invalidating a committed GTF_accept_transfer entry: *  1. Wait for (ent->flags & GTF_transfer_completed). * * Changing a GTF_permit_access from writable to read-only: *  Use SMP-safe CMPXCHG to set GTF_readonly, while checking !GTF_writing. * * Changing a GTF_permit_access from read-only to writable: *  Use SMP-safe bit-setting instruction. */ /* * Reference to a grant entry in a specified domain's grant table. */typedef uint32_t grant_ref_t; /* * A grant table comprises a packed array of grant entries in one or more * page frames shared between Xen and a guest. * [XEN]: This field is written by Xen and read by the sharing guest. * [GST]: This field is written by the guest and read by Xen. */ /* * Version 1 of the grant table entry structure is maintained purely * for backwards compatibility.  New guests should use version 2. */struct grant_entry_v1 {    /* GTF_xxx: various type and flag information.  [XEN,GST] */    uint16_t flags;    /* The domain being granted foreign privileges. [GST] */    domid_t  domid;    /*     * GTF_permit_access: Frame that @domid is allowed to map and access. [GST]     * GTF_accept_transfer: Frame whose ownership transferred by @domid. [XEN]     */    uint32_t frame;}; /* * Type of grant entry. *  GTF_invalid: This grant entry grants no privileges. *  GTF_permit_access: Allow @domid to map/access @frame. *  GTF_accept_transfer: Allow @domid to transfer ownership of one page frame *                       to this guest. Xen writes the page number to @frame. *  GTF_transitive: Allow @domid to transitively access a subrange of *                  @trans_grant in @trans_domid.  No mappings are allowed. */#define GTF_invalid         (0U<<0)#define GTF_permit_access   (1U<<0)#define GTF_accept_transfer (2U<<0)#define GTF_transitive      (3U<<0)#define GTF_type_mask       (3U<<0) /* * Subflags for GTF_permit_access. *  GTF_readonly: Restrict @domid to read-only mappings and accesses. [GST] *  GTF_reading: Grant entry is currently mapped for reading by @domid. [XEN] *  GTF_writing: Grant entry is currently mapped for writing by @domid. [XEN] *  GTF_sub_page: Grant access to only a subrange of the page.  @domid *                will only be allowed to copy from the grant, and not *                map it. [GST] */#define _GTF_readonly       (2)#define GTF_readonly        (1U<<_GTF_readonly)#define _GTF_reading        (3)#define GTF_reading         (1U<<_GTF_reading)#define _GTF_writing        (4)#define GTF_writing         (1U<<_GTF_writing)#define _GTF_sub_page       (8)#define GTF_sub_page        (1U<<_GTF_sub_page) /* * Subflags for GTF_accept_transfer: *  GTF_transfer_committed: Xen sets this flag to indicate that it is committed *      to transferring ownership of a page frame. When a guest sees this flag *      it must /not/ modify the grant entry until GTF_transfer_completed is *      set by Xen. *  GTF_transfer_completed: It is safe for the guest to spin-wait on this flag *      after reading GTF_transfer_committed. Xen will always write the frame *      address, followed by ORing this flag, in a timely manner. */#define _GTF_transfer_committed (2)#define GTF_transfer_committed  (1U<<_GTF_transfer_committed)#define _GTF_transfer_completed (3)#define GTF_transfer_completed  (1U<<_GTF_transfer_completed) /* * Version 2 grant table entries.  These fulfil the same role as * version 1 entries, but can represent more complicated operations. * Any given domain will have either a version 1 or a version 2 table, * and every entry in the table will be the same version. * * The interface by which domains use grant references does not depend * on the grant table version in use by the other domain. */ /* * Version 1 and version 2 grant entries share a common prefix.  The * fields of the prefix are documented as part of struct * grant_entry_v1. */struct grant_entry_header {    uint16_t flags;    domid_t  domid;}; /* * Version 2 of the grant entry structure, here is a union because three * different types are suppotted: full_page, sub_page and transitive. */union grant_entry_v2 {    struct grant_entry_header hdr;     /*     * This member is used for V1-style full page grants, where either:     *     * -- hdr.type is GTF_accept_transfer, or     * -- hdr.type is GTF_permit_access and GTF_sub_page is not set.     *     * In that case, the frame field has the same semantics as the     * field of the same name in the V1 entry structure.     */    struct {	struct grant_entry_header hdr;	uint32_t pad0;	uint64_t frame;    } full_page;     /*     * If the grant type is GTF_grant_access and GTF_sub_page is set,     * @domid is allowed to access bytes [@page_off,@page_off+@length)     * in frame @frame.     */    struct {	struct grant_entry_header hdr;	uint16_t page_off;	uint16_t length;	uint64_t frame;    } sub_page;     /*     * If the grant is GTF_transitive, @domid is allowed to use the     * grant @gref in domain @trans_domid, as if it was the local     * domain.  Obviously, the transitive access must be compatible     * with the original grant.     */    struct {	struct grant_entry_header hdr;	domid_t trans_domid;	uint16_t pad0;	grant_ref_t gref;    } transitive;     uint32_t __spacer[4]; /* Pad to a power of two */}; typedef uint16_t grant_status_t; /*********************************** * GRANT TABLE QUERIES AND USES */ /* * Handle to track a mapping created via a grant reference. */typedef uint32_t grant_handle_t; /* * GNTTABOP_map_grant_ref: Map the grant entry (<dom>,<ref>) for access * by devices and/or host CPUs. If successful, <handle> is a tracking number * that must be presented later to destroy the mapping(s). On error, <handle> * is a negative status code. * NOTES: *  1. If GNTMAP_device_map is specified then <dev_bus_addr> is the address *     via which I/O devices may access the granted frame. *  2. If GNTMAP_host_map is specified then a mapping will be added at *     either a host virtual address in the current address space, or at *     a PTE at the specified machine address.  The type of mapping to *     perform is selected through the GNTMAP_contains_pte flag, and the *     address is specified in <host_addr>. *  3. Mappings should only be destroyed via GNTTABOP_unmap_grant_ref. If a *     host mapping is destroyed by other means then it is *NOT* guaranteed *     to be accounted to the correct grant reference! */#define GNTTABOP_map_grant_ref        0struct gnttab_map_grant_ref {    /* IN parameters. */    uint64_t host_addr;    uint32_t flags;               /* GNTMAP_* */    grant_ref_t ref;    domid_t  dom;    /* OUT parameters. */    int16_t  status;              /* GNTST_* */    grant_handle_t handle;    uint64_t dev_bus_addr;};DEFINE_GUEST_HANDLE_STRUCT(gnttab_map_grant_ref); /* * GNTTABOP_unmap_grant_ref: Destroy one or more grant-reference mappings * tracked by <handle>. If <host_addr> or <dev_bus_addr> is zero, that * field is ignored. If non-zero, they must refer to a device/host mapping * that is tracked by <handle> * NOTES: *  1. The call may fail in an undefined manner if either mapping is not *     tracked by <handle>. *  3. After executing a batch of unmaps, it is guaranteed that no stale *     mappings will remain in the device or host TLBs. */#define GNTTABOP_unmap_grant_ref      1struct gnttab_unmap_grant_ref {    /* IN parameters. */    uint64_t host_addr;    uint64_t dev_bus_addr;    grant_handle_t handle;    /* OUT parameters. */    int16_t  status;              /* GNTST_* */};DEFINE_GUEST_HANDLE_STRUCT(gnttab_unmap_grant_ref); /* * GNTTABOP_setup_table: Set up a grant table for <dom> comprising at least * <nr_frames> pages. The frame addresses are written to the <frame_list>. * Only <nr_frames> addresses are written, even if the table is larger. * NOTES: *  1. <dom> may be specified as DOMID_SELF. *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF. *  3. Xen may not support more than a single grant-table page per domain. */#define GNTTABOP_setup_table          2struct gnttab_setup_table {    /* IN parameters. */    domid_t  dom;    uint32_t nr_frames;    /* OUT parameters. */    int16_t  status;              /* GNTST_* */    GUEST_HANDLE(xen_pfn_t) frame_list;};DEFINE_GUEST_HANDLE_STRUCT(gnttab_setup_table); /* * GNTTABOP_dump_table: Dump the contents of the grant table to the * xen console. Debugging use only. */#define GNTTABOP_dump_table           3struct gnttab_dump_table {    /* IN parameters. */    domid_t dom;    /* OUT parameters. */    int16_t status;               /* GNTST_* */};DEFINE_GUEST_HANDLE_STRUCT(gnttab_dump_table); /* * GNTTABOP_transfer_grant_ref: Transfer <frame> to a foreign domain. The * foreign domain has previously registered its interest in the transfer via * <domid, ref>. * * Note that, even if the transfer fails, the specified page no longer belongs * to the calling domain *unless* the error is GNTST_bad_page. */#define GNTTABOP_transfer                4struct gnttab_transfer {    /* IN parameters. */    xen_pfn_t mfn;    domid_t       domid;    grant_ref_t   ref;    /* OUT parameters. */    int16_t       status;};DEFINE_GUEST_HANDLE_STRUCT(gnttab_transfer); /* * GNTTABOP_copy: Hypervisor based copy * source and destinations can be eithers MFNs or, for foreign domains, * grant references. the foreign domain has to grant read/write access * in its grant table. * * The flags specify what type source and destinations are (either MFN * or grant reference). * * Note that this can also be used to copy data between two domains * via a third party if the source and destination domains had previously * grant appropriate access to their pages to the third party. * * source_offset specifies an offset in the source frame, dest_offset * the offset in the target frame and  len specifies the number of * bytes to be copied. */ #define _GNTCOPY_source_gref      (0)#define GNTCOPY_source_gref       (1<<_GNTCOPY_source_gref)#define _GNTCOPY_dest_gref        (1)#define GNTCOPY_dest_gref         (1<<_GNTCOPY_dest_gref) #define GNTTABOP_copy                 5struct gnttab_copy {	/* IN parameters. */	struct {		union {			grant_ref_t ref;			xen_pfn_t   gmfn;		} u;		domid_t  domid;		uint16_t offset;	} source, dest;	uint16_t      len;	uint16_t      flags;          /* GNTCOPY_* */	/* OUT parameters. */	int16_t       status;};DEFINE_GUEST_HANDLE_STRUCT(gnttab_copy); /* * GNTTABOP_query_size: Query the current and maximum sizes of the shared * grant table. * NOTES: *  1. <dom> may be specified as DOMID_SELF. *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF. */#define GNTTABOP_query_size           6struct gnttab_query_size {    /* IN parameters. */    domid_t  dom;    /* OUT parameters. */    uint32_t nr_frames;    uint32_t max_nr_frames;    int16_t  status;              /* GNTST_* */};DEFINE_GUEST_HANDLE_STRUCT(gnttab_query_size); /* * GNTTABOP_unmap_and_replace: Destroy one or more grant-reference mappings * tracked by <handle> but atomically replace the page table entry with one * pointing to the machine address under <new_addr>.  <new_addr> will be * redirected to the null entry. * NOTES: *  1. The call may fail in an undefined manner if either mapping is not *     tracked by <handle>. *  2. After executing a batch of unmaps, it is guaranteed that no stale *     mappings will remain in the device or host TLBs. */#define GNTTABOP_unmap_and_replace    7struct gnttab_unmap_and_replace {    /* IN parameters. */    uint64_t host_addr;    uint64_t new_addr;    grant_handle_t handle;    /* OUT parameters. */    int16_t  status;              /* GNTST_* */};DEFINE_GUEST_HANDLE_STRUCT(gnttab_unmap_and_replace); /* * GNTTABOP_set_version: Request a particular version of the grant * table shared table structure.  This operation can only be performed * once in any given domain.  It must be performed before any grants * are activated; otherwise, the domain will be stuck with version 1. * The only defined versions are 1 and 2. */#define GNTTABOP_set_version          8struct gnttab_set_version {    /* IN parameters */    uint32_t version;};DEFINE_GUEST_HANDLE_STRUCT(gnttab_set_version); /* * GNTTABOP_get_status_frames: Get the list of frames used to store grant * status for <dom>. In grant format version 2, the status is separated * from the other shared grant fields to allow more efficient synchronization * using barriers instead of atomic cmpexch operations. * <nr_frames> specify the size of vector <frame_list>. * The frame addresses are returned in the <frame_list>. * Only <nr_frames> addresses are returned, even if the table is larger. * NOTES: *  1. <dom> may be specified as DOMID_SELF. *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF. */#define GNTTABOP_get_status_frames     9struct gnttab_get_status_frames {    /* IN parameters. */    uint32_t nr_frames;    domid_t  dom;    /* OUT parameters. */    int16_t  status;              /* GNTST_* */    GUEST_HANDLE(uint64_t) frame_list;};DEFINE_GUEST_HANDLE_STRUCT(gnttab_get_status_frames); /* * GNTTABOP_get_version: Get the grant table version which is in * effect for domain <dom>. */#define GNTTABOP_get_version          10struct gnttab_get_version {    /* IN parameters */    domid_t dom;    uint16_t pad;    /* OUT parameters */    uint32_t version;};DEFINE_GUEST_HANDLE_STRUCT(gnttab_get_version); /* * Issue one or more cache maintenance operations on a portion of a * page granted to the calling domain by a foreign domain. */#define GNTTABOP_cache_flush          12struct gnttab_cache_flush {    union {        uint64_t dev_bus_addr;        grant_ref_t ref;    } a;    uint16_t offset;   /* offset from start of grant */    uint16_t length;   /* size within the grant */#define GNTTAB_CACHE_CLEAN          (1<<0)#define GNTTAB_CACHE_INVAL          (1<<1)#define GNTTAB_CACHE_SOURCE_GREF    (1<<31)    uint32_t op;};DEFINE_GUEST_HANDLE_STRUCT(gnttab_cache_flush); /*

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