1/******************************************************************************
2 * SPDX-License-Identifier: MIT OR GPL-2.0-only
3 *
4 * gnttab.h
5 *
6 * Two sets of functionality:
7 * 1. Granting foreign access to our memory reservation.
8 * 2. Accessing others' memory reservations via grant references.
9 * (i.e., mechanisms for both sender and recipient of grant references)
10 *
11 * Copyright (c) 2004-2005, K A Fraser
12 * Copyright (c) 2005, Christopher Clark
13 *
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License version 2
16 * as published by the Free Software Foundation; or, when distributed
17 * separately from the Linux kernel or incorporated into other
18 * software packages, subject to the following license:
19 *
20 * Permission is hereby granted, free of charge, to any person obtaining a copy
21 * of this source file (the "Software"), to deal in the Software without
22 * restriction, including without limitation the rights to use, copy, modify,
23 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
24 * and to permit persons to whom the Software is furnished to do so, subject to
25 * the following conditions:
26 *
27 * The above copyright notice and this permission notice shall be included in
28 * all copies or substantial portions of the Software.
29 *
30 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
31 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
32 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
33 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
34 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
35 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
36 * IN THE SOFTWARE.
37 */
38
39#ifndef __ASM_GNTTAB_H__
40#define __ASM_GNTTAB_H__
41
42#include <xen/xen-os.h>
43#include <xen/hypervisor.h>
44#include <xen/features.h>
45
46#include <contrib/xen/grant_table.h>
47
48#define GNTTAB_LIST_END GRANT_REF_INVALID
49
50struct gnttab_free_callback {
51	struct gnttab_free_callback *next;
52	void (*fn)(void *);
53	void *arg;
54	uint16_t count;
55};
56
57/*
58 * Allocate a grant table reference and return it in *result. Returns
59 * zero on success or errno on error.
60 */
61int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
62    int flags, grant_ref_t *result);
63
64/*
65 * End access through the given grant reference, iff the grant entry is no
66 * longer in use.  Return 1 if the grant entry was freed, 0 if it is still in
67 * use.
68 */
69int gnttab_end_foreign_access_ref(grant_ref_t ref);
70
71/*
72 * Eventually end access through the given grant reference, and once that
73 * access has been ended, free the given page too.  Access will be ended
74 * immediately iff the grant entry is not in use, otherwise it will happen
75 * some time later.  page may be 0, in which case no freeing will occur.
76 */
77void gnttab_end_foreign_access(grant_ref_t ref, void *page);
78
79/*
80 * Eventually end access through the given array of grant references.
81 * Access will be ended immediately iff the grant entry is not in use,
82 * otherwise it will happen some time later
83 */
84void gnttab_end_foreign_access_references(u_int count, grant_ref_t *refs);
85
86int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn, grant_ref_t *result);
87
88unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);
89unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);
90
91int gnttab_query_foreign_access(grant_ref_t ref);
92
93/*
94 * operations on reserved batches of grant references
95 */
96int gnttab_alloc_grant_references(uint16_t count, grant_ref_t *pprivate_head);
97
98void gnttab_free_grant_reference(grant_ref_t ref);
99
100void gnttab_free_grant_references(grant_ref_t head);
101
102int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
103
104int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
105
106void gnttab_release_grant_reference(grant_ref_t *private_head,
107				    grant_ref_t release);
108
109void gnttab_request_free_callback(struct gnttab_free_callback *callback,
110				  void (*fn)(void *), void *arg, uint16_t count);
111void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
112
113void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
114				     unsigned long frame, int flags);
115
116void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
117				       unsigned long pfn);
118
119int gnttab_suspend(void);
120int gnttab_resume(device_t);
121
122#endif /* __ASM_GNTTAB_H__ */
123