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(n: nr_frames, size: 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(mm: &init_mm, address: (unsigned long)area->area->addr, |
111 | PAGE_SIZE * nr_frames, fn: gnttab_apply, data: area)) |
112 | goto out_free_vm_area; |
113 | return 0; |
114 | out_free_vm_area: |
115 | free_vm_area(area: area->area); |
116 | out_free_ptes: |
117 | kfree(objp: 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->area); |
124 | kfree(objp: 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(area: &gnttab_shared_vm_area, nr_frames: 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(area: &gnttab_status_vm_area, nr_frames: nr_status); |
143 | if (ret < 0) |
144 | goto err; |
145 | |
146 | return 0; |
147 | err: |
148 | arch_gnttab_vfree(area: &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(pfns: &xen_auto_xlat_grant_frames.pfn, |
163 | vaddr: &xen_auto_xlat_grant_frames.vaddr, |
164 | nr_grant_frames: 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 | |