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Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +01001/*
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 */
Markus Armbruster0b8fa322019-05-23 16:35:07 +020012
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010013#include "qemu/osdep.h"
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010014#include "sysemu/hostmem.h"
15#include "sysemu/sysemu.h"
16#include "qom/object_interfaces.h"
17#include "qemu/memfd.h"
Markus Armbruster0b8fa322019-05-23 16:35:07 +020018#include "qemu/module.h"
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010019#include "qapi/error.h"
Eduardo Habkostdb1015e2020-09-03 16:43:22 -040020#include "qom/object.h"
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010021
22#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd"
23
Eduardo Habkost80633962020-09-16 14:25:19 -040024OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendMemfd, MEMORY_BACKEND_MEMFD)
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010025
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010026
27struct HostMemoryBackendMemfd {
28 HostMemoryBackend parent_obj;
29
30 bool hugetlb;
31 uint64_t hugetlbsize;
32 bool seal;
33};
34
35static void
36memfd_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
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010047 fd = qemu_memfd_create(TYPE_MEMORY_BACKEND_MEMFD, backend->size,
48 m->hugetlb, m->hugetlbsize, m->seal ?
49 F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL : 0,
50 errp);
51 if (fd == -1) {
52 return;
53 }
54
Marc-André Lureaufa0cb342018-09-12 16:18:00 +040055 name = host_memory_backend_get_name(backend);
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010056 memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend),
Marc-André Lureau36ea3972018-08-28 17:38:40 +020057 name, backend->size,
Jagannathan Raman44a4ff32021-01-29 11:46:04 -050058 backend->share, fd, 0, errp);
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010059 g_free(name);
60}
61
62static bool
63memfd_backend_get_hugetlb(Object *o, Error **errp)
64{
65 return MEMORY_BACKEND_MEMFD(o)->hugetlb;
66}
67
68static void
69memfd_backend_set_hugetlb(Object *o, bool value, Error **errp)
70{
71 MEMORY_BACKEND_MEMFD(o)->hugetlb = value;
72}
73
74static void
75memfd_backend_set_hugetlbsize(Object *obj, Visitor *v, const char *name,
76 void *opaque, Error **errp)
77{
78 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj);
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010079 uint64_t value;
80
81 if (host_memory_backend_mr_inited(MEMORY_BACKEND(obj))) {
Markus Armbrusterdcfe4802020-07-07 18:06:01 +020082 error_setg(errp, "cannot change property value");
83 return;
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010084 }
85
Markus Armbruster668f62e2020-07-07 18:06:02 +020086 if (!visit_type_size(v, name, &value, errp)) {
Markus Armbrusterdcfe4802020-07-07 18:06:01 +020087 return;
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010088 }
89 if (!value) {
Markus Armbrusterdcfe4802020-07-07 18:06:01 +020090 error_setg(errp, "Property '%s.%s' doesn't take value '%" PRIu64 "'",
91 object_get_typename(obj), name, value);
92 return;
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010093 }
94 m->hugetlbsize = value;
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +010095}
96
97static void
98memfd_backend_get_hugetlbsize(Object *obj, Visitor *v, const char *name,
99 void *opaque, Error **errp)
100{
101 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj);
102 uint64_t value = m->hugetlbsize;
103
104 visit_type_size(v, name, &value, errp);
105}
106
107static bool
108memfd_backend_get_seal(Object *o, Error **errp)
109{
110 return MEMORY_BACKEND_MEMFD(o)->seal;
111}
112
113static void
114memfd_backend_set_seal(Object *o, bool value, Error **errp)
115{
116 MEMORY_BACKEND_MEMFD(o)->seal = value;
117}
118
119static void
120memfd_backend_instance_init(Object *obj)
121{
122 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj);
123
124 /* default to sealed file */
125 m->seal = true;
Marc-André Lureau36ea3972018-08-28 17:38:40 +0200126 MEMORY_BACKEND(m)->share = true;
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +0100127}
128
129static void
130memfd_backend_class_init(ObjectClass *oc, void *data)
131{
132 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
133
134 bc->alloc = memfd_backend_memory_alloc;
135
Marc-André Lureau38296402018-09-06 20:14:15 +0400136 if (qemu_memfd_check(MFD_HUGETLB)) {
137 object_class_property_add_bool(oc, "hugetlb",
138 memfd_backend_get_hugetlb,
Markus Armbrusterd2623122020-05-05 17:29:22 +0200139 memfd_backend_set_hugetlb);
Marc-André Lureau033bfc52018-09-06 18:39:08 +0400140 object_class_property_set_description(oc, "hugetlb",
Markus Armbruster7eecec72020-05-05 17:29:15 +0200141 "Use huge pages");
Marc-André Lureau38296402018-09-06 20:14:15 +0400142 object_class_property_add(oc, "hugetlbsize", "int",
143 memfd_backend_get_hugetlbsize,
144 memfd_backend_set_hugetlbsize,
Markus Armbrusterd2623122020-05-05 17:29:22 +0200145 NULL, NULL);
Marc-André Lureau033bfc52018-09-06 18:39:08 +0400146 object_class_property_set_description(oc, "hugetlbsize",
Markus Armbruster7eecec72020-05-05 17:29:15 +0200147 "Huge pages size (ex: 2M, 1G)");
Marc-André Lureau38296402018-09-06 20:14:15 +0400148 }
Ilya Maximets4a66c7a2019-03-11 16:58:47 +0300149 object_class_property_add_bool(oc, "seal",
150 memfd_backend_get_seal,
Markus Armbrusterd2623122020-05-05 17:29:22 +0200151 memfd_backend_set_seal);
Ilya Maximets4a66c7a2019-03-11 16:58:47 +0300152 object_class_property_set_description(oc, "seal",
Markus Armbruster7eecec72020-05-05 17:29:15 +0200153 "Seal growing & shrinking");
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +0100154}
155
156static const TypeInfo memfd_backend_info = {
157 .name = TYPE_MEMORY_BACKEND_MEMFD,
158 .parent = TYPE_MEMORY_BACKEND,
159 .instance_init = memfd_backend_instance_init,
160 .class_init = memfd_backend_class_init,
161 .instance_size = sizeof(HostMemoryBackendMemfd),
162};
163
164static void register_types(void)
165{
Ilya Maximets4a66c7a2019-03-11 16:58:47 +0300166 if (qemu_memfd_check(MFD_ALLOW_SEALING)) {
Marc-André Lureau38296402018-09-06 20:14:15 +0400167 type_register_static(&memfd_backend_info);
168 }
Marc-André Lureaudbb9e0f2018-02-01 14:27:54 +0100169}
170
171type_init(register_types);