Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20211016' into staging
[qemu.git] / backends / hostmem-memfd.c
1 /*
2 * QEMU host memfd memory backend
3 *
4 * Copyright (C) 2018 Red Hat Inc
5 *
6 * Authors:
7 * Marc-André Lureau <marcandre.lureau@redhat.com>
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
13 #include "qemu/osdep.h"
14 #include "sysemu/hostmem.h"
15 #include "qom/object_interfaces.h"
16 #include "qemu/memfd.h"
17 #include "qemu/module.h"
18 #include "qapi/error.h"
19 #include "qom/object.h"
20
21 #define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd"
22
23 OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendMemfd, MEMORY_BACKEND_MEMFD)
24
25
26 struct HostMemoryBackendMemfd {
27 HostMemoryBackend parent_obj;
28
29 bool hugetlb;
30 uint64_t hugetlbsize;
31 bool seal;
32 };
33
34 static void
35 memfd_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
36 {
37 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(backend);
38 char *name;
39 int fd;
40
41 if (!backend->size) {
42 error_setg(errp, "can't create backend with size 0");
43 return;
44 }
45
46 fd = qemu_memfd_create(TYPE_MEMORY_BACKEND_MEMFD, backend->size,
47 m->hugetlb, m->hugetlbsize, m->seal ?
48 F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL : 0,
49 errp);
50 if (fd == -1) {
51 return;
52 }
53
54 name = host_memory_backend_get_name(backend);
55 memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend),
56 name, backend->size,
57 backend->share, fd, 0, errp);
58 g_free(name);
59 }
60
61 static bool
62 memfd_backend_get_hugetlb(Object *o, Error **errp)
63 {
64 return MEMORY_BACKEND_MEMFD(o)->hugetlb;
65 }
66
67 static void
68 memfd_backend_set_hugetlb(Object *o, bool value, Error **errp)
69 {
70 MEMORY_BACKEND_MEMFD(o)->hugetlb = value;
71 }
72
73 static void
74 memfd_backend_set_hugetlbsize(Object *obj, Visitor *v, const char *name,
75 void *opaque, Error **errp)
76 {
77 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj);
78 uint64_t value;
79
80 if (host_memory_backend_mr_inited(MEMORY_BACKEND(obj))) {
81 error_setg(errp, "cannot change property value");
82 return;
83 }
84
85 if (!visit_type_size(v, name, &value, errp)) {
86 return;
87 }
88 if (!value) {
89 error_setg(errp, "Property '%s.%s' doesn't take value '%" PRIu64 "'",
90 object_get_typename(obj), name, value);
91 return;
92 }
93 m->hugetlbsize = value;
94 }
95
96 static void
97 memfd_backend_get_hugetlbsize(Object *obj, Visitor *v, const char *name,
98 void *opaque, Error **errp)
99 {
100 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj);
101 uint64_t value = m->hugetlbsize;
102
103 visit_type_size(v, name, &value, errp);
104 }
105
106 static bool
107 memfd_backend_get_seal(Object *o, Error **errp)
108 {
109 return MEMORY_BACKEND_MEMFD(o)->seal;
110 }
111
112 static void
113 memfd_backend_set_seal(Object *o, bool value, Error **errp)
114 {
115 MEMORY_BACKEND_MEMFD(o)->seal = value;
116 }
117
118 static void
119 memfd_backend_instance_init(Object *obj)
120 {
121 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj);
122
123 /* default to sealed file */
124 m->seal = true;
125 MEMORY_BACKEND(m)->share = true;
126 }
127
128 static void
129 memfd_backend_class_init(ObjectClass *oc, void *data)
130 {
131 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
132
133 bc->alloc = memfd_backend_memory_alloc;
134
135 if (qemu_memfd_check(MFD_HUGETLB)) {
136 object_class_property_add_bool(oc, "hugetlb",
137 memfd_backend_get_hugetlb,
138 memfd_backend_set_hugetlb);
139 object_class_property_set_description(oc, "hugetlb",
140 "Use huge pages");
141 object_class_property_add(oc, "hugetlbsize", "int",
142 memfd_backend_get_hugetlbsize,
143 memfd_backend_set_hugetlbsize,
144 NULL, NULL);
145 object_class_property_set_description(oc, "hugetlbsize",
146 "Huge pages size (ex: 2M, 1G)");
147 }
148 object_class_property_add_bool(oc, "seal",
149 memfd_backend_get_seal,
150 memfd_backend_set_seal);
151 object_class_property_set_description(oc, "seal",
152 "Seal growing & shrinking");
153 }
154
155 static const TypeInfo memfd_backend_info = {
156 .name = TYPE_MEMORY_BACKEND_MEMFD,
157 .parent = TYPE_MEMORY_BACKEND,
158 .instance_init = memfd_backend_instance_init,
159 .class_init = memfd_backend_class_init,
160 .instance_size = sizeof(HostMemoryBackendMemfd),
161 };
162
163 static void register_types(void)
164 {
165 if (qemu_memfd_check(MFD_ALLOW_SEALING)) {
166 type_register_static(&memfd_backend_info);
167 }
168 }
169
170 type_init(register_types);