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1 | /* |
2 | * QEMU host memfd memory backend | |
3 | * | |
4 | * Copyright (C) 2018 Red Hat Inc | |
5 | * | |
6 | * Authors: | |
7 | * Marc-André Lureau <[email protected]> | |
8 | * | |
9 | * This work is licensed under the terms of the GNU GPL, version 2 or later. | |
10 | * See the COPYING file in the top-level directory. | |
11 | */ | |
12 | #include "qemu/osdep.h" | |
13 | #include "qemu-common.h" | |
14 | #include "sysemu/hostmem.h" | |
15 | #include "sysemu/sysemu.h" | |
16 | #include "qom/object_interfaces.h" | |
17 | #include "qemu/memfd.h" | |
18 | #include "qapi/error.h" | |
19 | ||
20 | #define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd" | |
21 | ||
22 | #define MEMORY_BACKEND_MEMFD(obj) \ | |
23 | OBJECT_CHECK(HostMemoryBackendMemfd, (obj), TYPE_MEMORY_BACKEND_MEMFD) | |
24 | ||
25 | typedef struct HostMemoryBackendMemfd HostMemoryBackendMemfd; | |
26 | ||
27 | struct HostMemoryBackendMemfd { | |
28 | HostMemoryBackend parent_obj; | |
29 | ||
30 | bool hugetlb; | |
31 | uint64_t hugetlbsize; | |
32 | bool seal; | |
33 | }; | |
34 | ||
35 | static void | |
36 | memfd_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) | |
37 | { | |
38 | HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(backend); | |
39 | char *name; | |
40 | int fd; | |
41 | ||
42 | if (!backend->size) { | |
43 | error_setg(errp, "can't create backend with size 0"); | |
44 | return; | |
45 | } | |
46 | ||
47 | if (host_memory_backend_mr_inited(backend)) { | |
48 | return; | |
49 | } | |
50 | ||
51 | backend->force_prealloc = mem_prealloc; | |
52 | fd = qemu_memfd_create(TYPE_MEMORY_BACKEND_MEMFD, backend->size, | |
53 | m->hugetlb, m->hugetlbsize, m->seal ? | |
54 | F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL : 0, | |
55 | errp); | |
56 | if (fd == -1) { | |
57 | return; | |
58 | } | |
59 | ||
60 | name = object_get_canonical_path(OBJECT(backend)); | |
61 | memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend), | |
62 | name, backend->size, true, fd, errp); | |
63 | g_free(name); | |
64 | } | |
65 | ||
66 | static bool | |
67 | memfd_backend_get_hugetlb(Object *o, Error **errp) | |
68 | { | |
69 | return MEMORY_BACKEND_MEMFD(o)->hugetlb; | |
70 | } | |
71 | ||
72 | static void | |
73 | memfd_backend_set_hugetlb(Object *o, bool value, Error **errp) | |
74 | { | |
75 | MEMORY_BACKEND_MEMFD(o)->hugetlb = value; | |
76 | } | |
77 | ||
78 | static void | |
79 | memfd_backend_set_hugetlbsize(Object *obj, Visitor *v, const char *name, | |
80 | void *opaque, Error **errp) | |
81 | { | |
82 | HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj); | |
83 | Error *local_err = NULL; | |
84 | uint64_t value; | |
85 | ||
86 | if (host_memory_backend_mr_inited(MEMORY_BACKEND(obj))) { | |
87 | error_setg(&local_err, "cannot change property value"); | |
88 | goto out; | |
89 | } | |
90 | ||
91 | visit_type_size(v, name, &value, &local_err); | |
92 | if (local_err) { | |
93 | goto out; | |
94 | } | |
95 | if (!value) { | |
96 | error_setg(&local_err, "Property '%s.%s' doesn't take value '%" | |
97 | PRIu64 "'", object_get_typename(obj), name, value); | |
98 | goto out; | |
99 | } | |
100 | m->hugetlbsize = value; | |
101 | out: | |
102 | error_propagate(errp, local_err); | |
103 | } | |
104 | ||
105 | static void | |
106 | memfd_backend_get_hugetlbsize(Object *obj, Visitor *v, const char *name, | |
107 | void *opaque, Error **errp) | |
108 | { | |
109 | HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj); | |
110 | uint64_t value = m->hugetlbsize; | |
111 | ||
112 | visit_type_size(v, name, &value, errp); | |
113 | } | |
114 | ||
115 | static bool | |
116 | memfd_backend_get_seal(Object *o, Error **errp) | |
117 | { | |
118 | return MEMORY_BACKEND_MEMFD(o)->seal; | |
119 | } | |
120 | ||
121 | static void | |
122 | memfd_backend_set_seal(Object *o, bool value, Error **errp) | |
123 | { | |
124 | MEMORY_BACKEND_MEMFD(o)->seal = value; | |
125 | } | |
126 | ||
127 | static void | |
128 | memfd_backend_instance_init(Object *obj) | |
129 | { | |
130 | HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj); | |
131 | ||
132 | /* default to sealed file */ | |
133 | m->seal = true; | |
134 | } | |
135 | ||
136 | static void | |
137 | memfd_backend_class_init(ObjectClass *oc, void *data) | |
138 | { | |
139 | HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); | |
140 | ||
141 | bc->alloc = memfd_backend_memory_alloc; | |
142 | ||
143 | object_class_property_add_bool(oc, "hugetlb", | |
144 | memfd_backend_get_hugetlb, | |
145 | memfd_backend_set_hugetlb, | |
146 | &error_abort); | |
147 | object_class_property_add(oc, "hugetlbsize", "int", | |
148 | memfd_backend_get_hugetlbsize, | |
149 | memfd_backend_set_hugetlbsize, | |
150 | NULL, NULL, &error_abort); | |
151 | object_class_property_add_bool(oc, "seal", | |
152 | memfd_backend_get_seal, | |
153 | memfd_backend_set_seal, | |
154 | &error_abort); | |
155 | } | |
156 | ||
157 | static const TypeInfo memfd_backend_info = { | |
158 | .name = TYPE_MEMORY_BACKEND_MEMFD, | |
159 | .parent = TYPE_MEMORY_BACKEND, | |
160 | .instance_init = memfd_backend_instance_init, | |
161 | .class_init = memfd_backend_class_init, | |
162 | .instance_size = sizeof(HostMemoryBackendMemfd), | |
163 | }; | |
164 | ||
165 | static void register_types(void) | |
166 | { | |
167 | type_register_static(&memfd_backend_info); | |
168 | } | |
169 | ||
170 | type_init(register_types); |