1 /******************************************************************************
2 * grant_table.c
3 * x86 specific part
4 *
5 * Granting foreign access to our memory reservation.
6 *
7 * Copyright (c) 2005-2006, Christopher Clark
8 * Copyright (c) 2004-2005, K A Fraser
9 * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
10 * VA Linux Systems Japan. Split out x86 specific part.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License version 2
14 * as published by the Free Software Foundation; or, when distributed
15 * separately from the Linux kernel or incorporated into other
16 * software packages, subject to the following license:
17 *
18 * Permission is hereby granted, free of charge, to any person obtaining a copy
19 * of this source file (the "Software"), to deal in the Software without
20 * restriction, including without limitation the rights to use, copy, modify,
21 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
22 * and to permit persons to whom the Software is furnished to do so, subject to
23 * the following conditions:
24 *
25 * The above copyright notice and this permission notice shall be included in
26 * all copies or substantial portions of the Software.
27 *
28 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
29 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
30 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
31 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
32 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
33 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
34 * IN THE SOFTWARE.
35 */
36
37 #include <linux/sched.h>
38 #include <linux/mm.h>
39 #include <linux/vmalloc.h>
40
41 #include <xen/interface/xen.h>
42 #include <xen/page.h>
43 #include <xen/grant_table.h>
44
45 #include <asm/pgtable.h>
46
map_pte_fn(pte_t * pte,struct page * pmd_page,unsigned long addr,void * data)47 static int map_pte_fn(pte_t *pte, struct page *pmd_page,
48 unsigned long addr, void *data)
49 {
50 unsigned long **frames = (unsigned long **)data;
51
52 set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL));
53 (*frames)++;
54 return 0;
55 }
56
57 /*
58 * This function is used to map shared frames to store grant status. It is
59 * different from map_pte_fn above, the frames type here is uint64_t.
60 */
map_pte_fn_status(pte_t * pte,struct page * pmd_page,unsigned long addr,void * data)61 static int map_pte_fn_status(pte_t *pte, struct page *pmd_page,
62 unsigned long addr, void *data)
63 {
64 uint64_t **frames = (uint64_t **)data;
65
66 set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL));
67 (*frames)++;
68 return 0;
69 }
70
unmap_pte_fn(pte_t * pte,struct page * pmd_page,unsigned long addr,void * data)71 static int unmap_pte_fn(pte_t *pte, struct page *pmd_page,
72 unsigned long addr, void *data)
73 {
74
75 set_pte_at(&init_mm, addr, pte, __pte(0));
76 return 0;
77 }
78
arch_gnttab_map_shared(unsigned long * frames,unsigned long nr_gframes,unsigned long max_nr_gframes,void ** __shared)79 int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
80 unsigned long max_nr_gframes,
81 void **__shared)
82 {
83 int rc;
84 void *shared = *__shared;
85
86 if (shared == NULL) {
87 struct vm_struct *area =
88 alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL);
89 BUG_ON(area == NULL);
90 shared = area->addr;
91 *__shared = shared;
92 }
93
94 rc = apply_to_page_range(&init_mm, (unsigned long)shared,
95 PAGE_SIZE * nr_gframes,
96 map_pte_fn, &frames);
97 return rc;
98 }
99
arch_gnttab_map_status(uint64_t * frames,unsigned long nr_gframes,unsigned long max_nr_gframes,grant_status_t ** __shared)100 int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
101 unsigned long max_nr_gframes,
102 grant_status_t **__shared)
103 {
104 int rc;
105 grant_status_t *shared = *__shared;
106
107 if (shared == NULL) {
108 /* No need to pass in PTE as we are going to do it
109 * in apply_to_page_range anyhow. */
110 struct vm_struct *area =
111 alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL);
112 BUG_ON(area == NULL);
113 shared = area->addr;
114 *__shared = shared;
115 }
116
117 rc = apply_to_page_range(&init_mm, (unsigned long)shared,
118 PAGE_SIZE * nr_gframes,
119 map_pte_fn_status, &frames);
120 return rc;
121 }
122
arch_gnttab_unmap(void * shared,unsigned long nr_gframes)123 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
124 {
125 apply_to_page_range(&init_mm, (unsigned long)shared,
126 PAGE_SIZE * nr_gframes, unmap_pte_fn, NULL);
127 }
128