2 * QEMU host memfd memory backend
4 * Copyright (C) 2018 Red Hat Inc
7 * Marc-André Lureau <marcandre.lureau@redhat.com>
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.
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"
21 #define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd"
23 OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendMemfd
, MEMORY_BACKEND_MEMFD
)
26 struct HostMemoryBackendMemfd
{
27 HostMemoryBackend parent_obj
;
35 memfd_backend_memory_alloc(HostMemoryBackend
*backend
, Error
**errp
)
37 HostMemoryBackendMemfd
*m
= MEMORY_BACKEND_MEMFD(backend
);
42 error_setg(errp
, "can't create backend with size 0");
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,
54 name
= host_memory_backend_get_name(backend
);
55 memory_region_init_ram_from_fd(&backend
->mr
, OBJECT(backend
),
57 backend
->share
, fd
, 0, errp
);
62 memfd_backend_get_hugetlb(Object
*o
, Error
**errp
)
64 return MEMORY_BACKEND_MEMFD(o
)->hugetlb
;
68 memfd_backend_set_hugetlb(Object
*o
, bool value
, Error
**errp
)
70 MEMORY_BACKEND_MEMFD(o
)->hugetlb
= value
;
74 memfd_backend_set_hugetlbsize(Object
*obj
, Visitor
*v
, const char *name
,
75 void *opaque
, Error
**errp
)
77 HostMemoryBackendMemfd
*m
= MEMORY_BACKEND_MEMFD(obj
);
80 if (host_memory_backend_mr_inited(MEMORY_BACKEND(obj
))) {
81 error_setg(errp
, "cannot change property value");
85 if (!visit_type_size(v
, name
, &value
, errp
)) {
89 error_setg(errp
, "Property '%s.%s' doesn't take value '%" PRIu64
"'",
90 object_get_typename(obj
), name
, value
);
93 m
->hugetlbsize
= value
;
97 memfd_backend_get_hugetlbsize(Object
*obj
, Visitor
*v
, const char *name
,
98 void *opaque
, Error
**errp
)
100 HostMemoryBackendMemfd
*m
= MEMORY_BACKEND_MEMFD(obj
);
101 uint64_t value
= m
->hugetlbsize
;
103 visit_type_size(v
, name
, &value
, errp
);
107 memfd_backend_get_seal(Object
*o
, Error
**errp
)
109 return MEMORY_BACKEND_MEMFD(o
)->seal
;
113 memfd_backend_set_seal(Object
*o
, bool value
, Error
**errp
)
115 MEMORY_BACKEND_MEMFD(o
)->seal
= value
;
119 memfd_backend_instance_init(Object
*obj
)
121 HostMemoryBackendMemfd
*m
= MEMORY_BACKEND_MEMFD(obj
);
123 /* default to sealed file */
125 MEMORY_BACKEND(m
)->share
= true;
129 memfd_backend_class_init(ObjectClass
*oc
, void *data
)
131 HostMemoryBackendClass
*bc
= MEMORY_BACKEND_CLASS(oc
);
133 bc
->alloc
= memfd_backend_memory_alloc
;
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",
141 object_class_property_add(oc
, "hugetlbsize", "int",
142 memfd_backend_get_hugetlbsize
,
143 memfd_backend_set_hugetlbsize
,
145 object_class_property_set_description(oc
, "hugetlbsize",
146 "Huge pages size (ex: 2M, 1G)");
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");
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
),
163 static void register_types(void)
165 if (qemu_memfd_check(MFD_ALLOW_SEALING
)) {
166 type_register_static(&memfd_backend_info
);
170 type_init(register_types
);