1 // SPDX-License-Identifier: GPL-2.0 OR MIT
2 /******************************************************************************
3 * grant_table.c
4 * x86 specific part
5 *
6 * Granting foreign access to our memory reservation.
7 *
8 * Copyright (c) 2005-2006, Christopher Clark
9 * Copyright (c) 2004-2005, K A Fraser
10 * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
11 * VA Linux Systems Japan. Split out x86 specific part.
12 */
13
14 #include <linux/sched.h>
15 #include <linux/mm.h>
16 #include <linux/slab.h>
17 #include <linux/vmalloc.h>
18
19 #include <xen/interface/xen.h>
20 #include <xen/page.h>
21 #include <xen/grant_table.h>
22 #include <xen/xen.h>
23
24
25 static struct gnttab_vm_area {
26 struct vm_struct *area;
27 pte_t **ptes;
28 int idx;
29 } gnttab_shared_vm_area, gnttab_status_vm_area;
30
31 int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
32 unsigned long max_nr_gframes,
33 void **__shared)
34 {
35 void *shared = *__shared;
36 unsigned long addr;
37 unsigned long i;
38
39 if (shared == NULL)
40 *__shared = shared = gnttab_shared_vm_area.area->addr;
41
42 addr = (unsigned long)shared;
43
44 for (i = 0; i < nr_gframes; i++) {
45 set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i],
46 mfn_pte(frames[i], PAGE_KERNEL));
47 addr += PAGE_SIZE;
48 }
49
50 return 0;
51 }
52
53 int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
54 unsigned long max_nr_gframes,
55 grant_status_t **__shared)
56 {
57 grant_status_t *shared = *__shared;
58 unsigned long addr;
59 unsigned long i;
60
61 if (shared == NULL)
62 *__shared = shared = gnttab_status_vm_area.area->addr;
63
64 addr = (unsigned long)shared;
65
66 for (i = 0; i < nr_gframes; i++) {
67 set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i],
68 mfn_pte(frames[i], PAGE_KERNEL));
69 addr += PAGE_SIZE;
70 }
71
72 return 0;
73 }
74
75 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
76 {
77 pte_t **ptes;
78 unsigned long addr;
79 unsigned long i;
80
81 if (shared == gnttab_status_vm_area.area->addr)
82 ptes = gnttab_status_vm_area.ptes;
83 else
84 ptes = gnttab_shared_vm_area.ptes;
85
86 addr = (unsigned long)shared;
87
88 for (i = 0; i < nr_gframes; i++) {
89 set_pte_at(&init_mm, addr, ptes[i], __pte(0));
90 addr += PAGE_SIZE;
91 }
92 }
93
94 static int gnttab_apply(pte_t *pte, unsigned long addr, void *data)
95 {
96 struct gnttab_vm_area *area = data;
97
98 area->ptes[area->idx++] = pte;
99 return 0;
100 }
101
102 static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames)
103 {
104 area->ptes = kmalloc_array(nr_frames, sizeof(*area->ptes), GFP_KERNEL);
105 if (area->ptes == NULL)
106 return -ENOMEM;
107 area->area = get_vm_area(PAGE_SIZE * nr_frames, VM_IOREMAP);
108 if (!area->area)
109 goto out_free_ptes;
110 if (apply_to_page_range(&init_mm, (unsigned long)area->area->addr,
111 PAGE_SIZE * nr_frames, gnttab_apply, area))
112 goto out_free_vm_area;
113 return 0;
114 out_free_vm_area:
115 free_vm_area(area->area);
116 out_free_ptes:
117 kfree(area->ptes);
118 return -ENOMEM;
119 }
120
121 static void arch_gnttab_vfree(struct gnttab_vm_area *area)
122 {
123 free_vm_area(area->area);
124 kfree(area->ptes);
125 }
126
127 int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status)
128 {
129 int ret;
130
131 if (!xen_pv_domain())
132 return 0;
133
134 ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
135 if (ret < 0)
136 return ret;
137
138 /*
139 * Always allocate the space for the status frames in case
140 * we're migrated to a host with V2 support.
141 */
142 ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status);
143 if (ret < 0)
144 goto err;
145
146 return 0;
147 err:
148 arch_gnttab_vfree(&gnttab_shared_vm_area);
149 return -ENOMEM;
150 }
151
152 #ifdef CONFIG_XEN_PVH
153 #include <xen/events.h>
154 #include <xen/xen-ops.h>
155 static int __init xen_pvh_gnttab_setup(void)
156 {
157 if (!xen_pvh_domain())
158 return -ENODEV;
159
160 xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames();
161
162 return xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn,
163 &xen_auto_xlat_grant_frames.vaddr,
164 xen_auto_xlat_grant_frames.count);
165 }
166 /* Call it _before_ __gnttab_init as we need to initialize the
167 * xen_auto_xlat_grant_frames first. */
168 core_initcall(xen_pvh_gnttab_setup);
169 #endif
170
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