1 /* 2 * QEMU Host Memory Backend for hugetlbfs 3 * 4 * Copyright (C) 2013-2014 Red Hat Inc 5 * 6 * Authors: 7 * Paolo Bonzini <pbonzini@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 "qapi/error.h" 15 #include "qemu/error-report.h" 16 #include "qemu/module.h" 17 #include "qemu/madvise.h" 18 #include "sysemu/hostmem.h" 19 #include "qom/object_interfaces.h" 20 #include "qom/object.h" 21 #include "qapi/visitor.h" 22 #include "qapi/qapi-visit-common.h" 23 24 OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendFile, MEMORY_BACKEND_FILE) 25 26 27 struct HostMemoryBackendFile { 28 HostMemoryBackend parent_obj; 29 30 char *mem_path; 31 uint64_t align; 32 uint64_t offset; 33 bool discard_data; 34 bool is_pmem; 35 bool readonly; 36 OnOffAuto rom; 37 }; 38 39 static bool 40 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 41 { 42 #ifndef CONFIG_POSIX 43 error_setg(errp, "backend '%s' not supported on this host", 44 object_get_typename(OBJECT(backend))); 45 return false; 46 #else 47 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend); 48 g_autofree gchar *name = NULL; 49 uint32_t ram_flags; 50 51 if (!backend->size) { 52 error_setg(errp, "can't create backend with size 0"); 53 return false; 54 } 55 if (!fb->mem_path) { 56 error_setg(errp, "mem-path property not set"); 57 return false; 58 } 59 60 switch (fb->rom) { 61 case ON_OFF_AUTO_AUTO: 62 /* Traditionally, opening the file readonly always resulted in ROM. */ 63 fb->rom = fb->readonly ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF; 64 break; 65 case ON_OFF_AUTO_ON: 66 if (!fb->readonly) { 67 error_setg(errp, "property 'rom' = 'on' is not supported with" 68 " 'readonly' = 'off'"); 69 return false; 70 } 71 break; 72 case ON_OFF_AUTO_OFF: 73 if (fb->readonly && backend->share) { 74 error_setg(errp, "property 'rom' = 'off' is incompatible with" 75 " 'readonly' = 'on' and 'share' = 'on'"); 76 return false; 77 } 78 break; 79 default: 80 g_assert_not_reached(); 81 } 82 83 name = host_memory_backend_get_name(backend); 84 ram_flags = backend->share ? RAM_SHARED : 0; 85 ram_flags |= fb->readonly ? RAM_READONLY_FD : 0; 86 ram_flags |= fb->rom == ON_OFF_AUTO_ON ? RAM_READONLY : 0; 87 ram_flags |= backend->reserve ? 0 : RAM_NORESERVE; 88 ram_flags |= fb->is_pmem ? RAM_PMEM : 0; 89 ram_flags |= RAM_NAMED_FILE; 90 return memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name, 91 backend->size, fb->align, ram_flags, 92 fb->mem_path, fb->offset, errp); 93 #endif 94 } 95 96 static char *get_mem_path(Object *o, Error **errp) 97 { 98 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 99 100 return g_strdup(fb->mem_path); 101 } 102 103 static void set_mem_path(Object *o, const char *str, Error **errp) 104 { 105 HostMemoryBackend *backend = MEMORY_BACKEND(o); 106 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 107 108 if (host_memory_backend_mr_inited(backend)) { 109 error_setg(errp, "cannot change property 'mem-path' of %s", 110 object_get_typename(o)); 111 return; 112 } 113 g_free(fb->mem_path); 114 fb->mem_path = g_strdup(str); 115 } 116 117 static bool file_memory_backend_get_discard_data(Object *o, Error **errp) 118 { 119 return MEMORY_BACKEND_FILE(o)->discard_data; 120 } 121 122 static void file_memory_backend_set_discard_data(Object *o, bool value, 123 Error **errp) 124 { 125 MEMORY_BACKEND_FILE(o)->discard_data = value; 126 } 127 128 static void file_memory_backend_get_align(Object *o, Visitor *v, 129 const char *name, void *opaque, 130 Error **errp) 131 { 132 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 133 uint64_t val = fb->align; 134 135 visit_type_size(v, name, &val, errp); 136 } 137 138 static void file_memory_backend_set_align(Object *o, Visitor *v, 139 const char *name, void *opaque, 140 Error **errp) 141 { 142 HostMemoryBackend *backend = MEMORY_BACKEND(o); 143 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 144 uint64_t val; 145 146 if (host_memory_backend_mr_inited(backend)) { 147 error_setg(errp, "cannot change property '%s' of %s", name, 148 object_get_typename(o)); 149 return; 150 } 151 152 if (!visit_type_size(v, name, &val, errp)) { 153 return; 154 } 155 fb->align = val; 156 } 157 158 static void file_memory_backend_get_offset(Object *o, Visitor *v, 159 const char *name, void *opaque, 160 Error **errp) 161 { 162 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 163 uint64_t val = fb->offset; 164 165 visit_type_size(v, name, &val, errp); 166 } 167 168 static void file_memory_backend_set_offset(Object *o, Visitor *v, 169 const char *name, void *opaque, 170 Error **errp) 171 { 172 HostMemoryBackend *backend = MEMORY_BACKEND(o); 173 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 174 uint64_t val; 175 176 if (host_memory_backend_mr_inited(backend)) { 177 error_setg(errp, "cannot change property '%s' of %s", name, 178 object_get_typename(o)); 179 return; 180 } 181 182 if (!visit_type_size(v, name, &val, errp)) { 183 return; 184 } 185 fb->offset = val; 186 } 187 188 #ifdef CONFIG_LIBPMEM 189 static bool file_memory_backend_get_pmem(Object *o, Error **errp) 190 { 191 return MEMORY_BACKEND_FILE(o)->is_pmem; 192 } 193 194 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp) 195 { 196 HostMemoryBackend *backend = MEMORY_BACKEND(o); 197 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 198 199 if (host_memory_backend_mr_inited(backend)) { 200 error_setg(errp, "cannot change property 'pmem' of %s.", 201 object_get_typename(o)); 202 return; 203 } 204 205 fb->is_pmem = value; 206 } 207 #endif /* CONFIG_LIBPMEM */ 208 209 static bool file_memory_backend_get_readonly(Object *obj, Error **errp) 210 { 211 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 212 213 return fb->readonly; 214 } 215 216 static void file_memory_backend_set_readonly(Object *obj, bool value, 217 Error **errp) 218 { 219 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 220 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 221 222 if (host_memory_backend_mr_inited(backend)) { 223 error_setg(errp, "cannot change property 'readonly' of %s.", 224 object_get_typename(obj)); 225 return; 226 } 227 228 fb->readonly = value; 229 } 230 231 static void file_memory_backend_get_rom(Object *obj, Visitor *v, 232 const char *name, void *opaque, 233 Error **errp) 234 { 235 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 236 OnOffAuto rom = fb->rom; 237 238 visit_type_OnOffAuto(v, name, &rom, errp); 239 } 240 241 static void file_memory_backend_set_rom(Object *obj, Visitor *v, 242 const char *name, void *opaque, 243 Error **errp) 244 { 245 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 246 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 247 248 if (host_memory_backend_mr_inited(backend)) { 249 error_setg(errp, "cannot change property '%s' of %s.", name, 250 object_get_typename(obj)); 251 return; 252 } 253 254 visit_type_OnOffAuto(v, name, &fb->rom, errp); 255 } 256 257 static void file_backend_unparent(Object *obj) 258 { 259 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 260 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 261 262 if (host_memory_backend_mr_inited(backend) && fb->discard_data) { 263 void *ptr = memory_region_get_ram_ptr(&backend->mr); 264 uint64_t sz = memory_region_size(&backend->mr); 265 266 qemu_madvise(ptr, sz, QEMU_MADV_REMOVE); 267 } 268 } 269 270 static void 271 file_backend_class_init(ObjectClass *oc, void *data) 272 { 273 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 274 275 bc->alloc = file_backend_memory_alloc; 276 oc->unparent = file_backend_unparent; 277 278 object_class_property_add_bool(oc, "discard-data", 279 file_memory_backend_get_discard_data, file_memory_backend_set_discard_data); 280 object_class_property_add_str(oc, "mem-path", 281 get_mem_path, set_mem_path); 282 object_class_property_add(oc, "align", "int", 283 file_memory_backend_get_align, 284 file_memory_backend_set_align, 285 NULL, NULL); 286 object_class_property_add(oc, "offset", "int", 287 file_memory_backend_get_offset, 288 file_memory_backend_set_offset, 289 NULL, NULL); 290 object_class_property_set_description(oc, "offset", 291 "Offset into the target file (ex: 1G)"); 292 #ifdef CONFIG_LIBPMEM 293 object_class_property_add_bool(oc, "pmem", 294 file_memory_backend_get_pmem, file_memory_backend_set_pmem); 295 #endif 296 object_class_property_add_bool(oc, "readonly", 297 file_memory_backend_get_readonly, 298 file_memory_backend_set_readonly); 299 object_class_property_add(oc, "rom", "OnOffAuto", 300 file_memory_backend_get_rom, file_memory_backend_set_rom, NULL, NULL); 301 object_class_property_set_description(oc, "rom", 302 "Whether to create Read Only Memory (ROM)"); 303 } 304 305 static void file_backend_instance_finalize(Object *o) 306 { 307 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 308 309 g_free(fb->mem_path); 310 } 311 312 static const TypeInfo file_backend_info = { 313 .name = TYPE_MEMORY_BACKEND_FILE, 314 .parent = TYPE_MEMORY_BACKEND, 315 .class_init = file_backend_class_init, 316 .instance_finalize = file_backend_instance_finalize, 317 .instance_size = sizeof(HostMemoryBackendFile), 318 }; 319 320 static void register_types(void) 321 { 322 type_register_static(&file_backend_info); 323 } 324 325 type_init(register_types); 326