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 "sysemu/sysemu.h" 16 #include "qom/object_interfaces.h" 17 #include "qemu/memfd.h" 18 #include "qemu/module.h" 19 #include "qapi/error.h" 20 21 #define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd" 22 23 #define MEMORY_BACKEND_MEMFD(obj) \ 24 OBJECT_CHECK(HostMemoryBackendMemfd, (obj), TYPE_MEMORY_BACKEND_MEMFD) 25 26 typedef struct HostMemoryBackendMemfd HostMemoryBackendMemfd; 27 28 struct HostMemoryBackendMemfd { 29 HostMemoryBackend parent_obj; 30 31 bool hugetlb; 32 uint64_t hugetlbsize; 33 bool seal; 34 }; 35 36 static void 37 memfd_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 38 { 39 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(backend); 40 char *name; 41 int fd; 42 43 if (!backend->size) { 44 error_setg(errp, "can't create backend with size 0"); 45 return; 46 } 47 48 fd = qemu_memfd_create(TYPE_MEMORY_BACKEND_MEMFD, backend->size, 49 m->hugetlb, m->hugetlbsize, m->seal ? 50 F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL : 0, 51 errp); 52 if (fd == -1) { 53 return; 54 } 55 56 name = host_memory_backend_get_name(backend); 57 memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend), 58 name, backend->size, 59 backend->share, fd, errp); 60 g_free(name); 61 } 62 63 static bool 64 memfd_backend_get_hugetlb(Object *o, Error **errp) 65 { 66 return MEMORY_BACKEND_MEMFD(o)->hugetlb; 67 } 68 69 static void 70 memfd_backend_set_hugetlb(Object *o, bool value, Error **errp) 71 { 72 MEMORY_BACKEND_MEMFD(o)->hugetlb = value; 73 } 74 75 static void 76 memfd_backend_set_hugetlbsize(Object *obj, Visitor *v, const char *name, 77 void *opaque, Error **errp) 78 { 79 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj); 80 Error *local_err = NULL; 81 uint64_t value; 82 83 if (host_memory_backend_mr_inited(MEMORY_BACKEND(obj))) { 84 error_setg(&local_err, "cannot change property value"); 85 goto out; 86 } 87 88 visit_type_size(v, name, &value, &local_err); 89 if (local_err) { 90 goto out; 91 } 92 if (!value) { 93 error_setg(&local_err, "Property '%s.%s' doesn't take value '%" 94 PRIu64 "'", object_get_typename(obj), name, value); 95 goto out; 96 } 97 m->hugetlbsize = value; 98 out: 99 error_propagate(errp, local_err); 100 } 101 102 static void 103 memfd_backend_get_hugetlbsize(Object *obj, Visitor *v, const char *name, 104 void *opaque, Error **errp) 105 { 106 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj); 107 uint64_t value = m->hugetlbsize; 108 109 visit_type_size(v, name, &value, errp); 110 } 111 112 static bool 113 memfd_backend_get_seal(Object *o, Error **errp) 114 { 115 return MEMORY_BACKEND_MEMFD(o)->seal; 116 } 117 118 static void 119 memfd_backend_set_seal(Object *o, bool value, Error **errp) 120 { 121 MEMORY_BACKEND_MEMFD(o)->seal = value; 122 } 123 124 static void 125 memfd_backend_instance_init(Object *obj) 126 { 127 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj); 128 129 /* default to sealed file */ 130 m->seal = true; 131 MEMORY_BACKEND(m)->share = true; 132 } 133 134 static void 135 memfd_backend_class_init(ObjectClass *oc, void *data) 136 { 137 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 138 139 bc->alloc = memfd_backend_memory_alloc; 140 141 if (qemu_memfd_check(MFD_HUGETLB)) { 142 object_class_property_add_bool(oc, "hugetlb", 143 memfd_backend_get_hugetlb, 144 memfd_backend_set_hugetlb); 145 object_class_property_set_description(oc, "hugetlb", 146 "Use huge pages"); 147 object_class_property_add(oc, "hugetlbsize", "int", 148 memfd_backend_get_hugetlbsize, 149 memfd_backend_set_hugetlbsize, 150 NULL, NULL); 151 object_class_property_set_description(oc, "hugetlbsize", 152 "Huge pages size (ex: 2M, 1G)"); 153 } 154 object_class_property_add_bool(oc, "seal", 155 memfd_backend_get_seal, 156 memfd_backend_set_seal); 157 object_class_property_set_description(oc, "seal", 158 "Seal growing & shrinking"); 159 } 160 161 static const TypeInfo memfd_backend_info = { 162 .name = TYPE_MEMORY_BACKEND_MEMFD, 163 .parent = TYPE_MEMORY_BACKEND, 164 .instance_init = memfd_backend_instance_init, 165 .class_init = memfd_backend_class_init, 166 .instance_size = sizeof(HostMemoryBackendMemfd), 167 }; 168 169 static void register_types(void) 170 { 171 if (qemu_memfd_check(MFD_ALLOW_SEALING)) { 172 type_register_static(&memfd_backend_info); 173 } 174 } 175 176 type_init(register_types); 177