vmstate.c (17302B)
1 /* 2 * VMState interpreter 3 * 4 * Copyright (c) 2009-2017 Red Hat Inc 5 * 6 * Authors: 7 * Juan Quintela <quintela@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 "migration.h" 15 #include "migration/vmstate.h" 16 #include "savevm.h" 17 #include "qapi/qmp/json-writer.h" 18 #include "qemu-file.h" 19 #include "qemu/bitops.h" 20 #include "qemu/error-report.h" 21 #include "trace.h" 22 23 static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd, 24 void *opaque, JSONWriter *vmdesc); 25 static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, 26 void *opaque); 27 28 static int vmstate_n_elems(void *opaque, const VMStateField *field) 29 { 30 int n_elems = 1; 31 32 if (field->flags & VMS_ARRAY) { 33 n_elems = field->num; 34 } else if (field->flags & VMS_VARRAY_INT32) { 35 n_elems = *(int32_t *)(opaque + field->num_offset); 36 } else if (field->flags & VMS_VARRAY_UINT32) { 37 n_elems = *(uint32_t *)(opaque + field->num_offset); 38 } else if (field->flags & VMS_VARRAY_UINT16) { 39 n_elems = *(uint16_t *)(opaque + field->num_offset); 40 } else if (field->flags & VMS_VARRAY_UINT8) { 41 n_elems = *(uint8_t *)(opaque + field->num_offset); 42 } 43 44 if (field->flags & VMS_MULTIPLY_ELEMENTS) { 45 n_elems *= field->num; 46 } 47 48 trace_vmstate_n_elems(field->name, n_elems); 49 return n_elems; 50 } 51 52 static int vmstate_size(void *opaque, const VMStateField *field) 53 { 54 int size = field->size; 55 56 if (field->flags & VMS_VBUFFER) { 57 size = *(int32_t *)(opaque + field->size_offset); 58 if (field->flags & VMS_MULTIPLY) { 59 size *= field->size; 60 } 61 } 62 63 return size; 64 } 65 66 static void vmstate_handle_alloc(void *ptr, const VMStateField *field, 67 void *opaque) 68 { 69 if (field->flags & VMS_POINTER && field->flags & VMS_ALLOC) { 70 gsize size = vmstate_size(opaque, field); 71 size *= vmstate_n_elems(opaque, field); 72 if (size) { 73 *(void **)ptr = g_malloc(size); 74 } 75 } 76 } 77 78 int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd, 79 void *opaque, int version_id) 80 { 81 const VMStateField *field = vmsd->fields; 82 int ret = 0; 83 84 trace_vmstate_load_state(vmsd->name, version_id); 85 if (version_id > vmsd->version_id) { 86 error_report("%s: incoming version_id %d is too new " 87 "for local version_id %d", 88 vmsd->name, version_id, vmsd->version_id); 89 trace_vmstate_load_state_end(vmsd->name, "too new", -EINVAL); 90 return -EINVAL; 91 } 92 if (version_id < vmsd->minimum_version_id) { 93 error_report("%s: incoming version_id %d is too old " 94 "for local minimum version_id %d", 95 vmsd->name, version_id, vmsd->minimum_version_id); 96 trace_vmstate_load_state_end(vmsd->name, "too old", -EINVAL); 97 return -EINVAL; 98 } 99 if (vmsd->pre_load) { 100 int ret = vmsd->pre_load(opaque); 101 if (ret) { 102 return ret; 103 } 104 } 105 while (field->name) { 106 trace_vmstate_load_state_field(vmsd->name, field->name); 107 if ((field->field_exists && 108 field->field_exists(opaque, version_id)) || 109 (!field->field_exists && 110 field->version_id <= version_id)) { 111 void *first_elem = opaque + field->offset; 112 int i, n_elems = vmstate_n_elems(opaque, field); 113 int size = vmstate_size(opaque, field); 114 115 vmstate_handle_alloc(first_elem, field, opaque); 116 if (field->flags & VMS_POINTER) { 117 first_elem = *(void **)first_elem; 118 assert(first_elem || !n_elems || !size); 119 } 120 for (i = 0; i < n_elems; i++) { 121 void *curr_elem = first_elem + size * i; 122 123 if (field->flags & VMS_ARRAY_OF_POINTER) { 124 curr_elem = *(void **)curr_elem; 125 } 126 if (!curr_elem && size) { 127 /* if null pointer check placeholder and do not follow */ 128 assert(field->flags & VMS_ARRAY_OF_POINTER); 129 ret = vmstate_info_nullptr.get(f, curr_elem, size, NULL); 130 } else if (field->flags & VMS_STRUCT) { 131 ret = vmstate_load_state(f, field->vmsd, curr_elem, 132 field->vmsd->version_id); 133 } else if (field->flags & VMS_VSTRUCT) { 134 ret = vmstate_load_state(f, field->vmsd, curr_elem, 135 field->struct_version_id); 136 } else { 137 ret = field->info->get(f, curr_elem, size, field); 138 } 139 if (ret >= 0) { 140 ret = qemu_file_get_error(f); 141 } 142 if (ret < 0) { 143 qemu_file_set_error(f, ret); 144 error_report("Failed to load %s:%s", vmsd->name, 145 field->name); 146 trace_vmstate_load_field_error(field->name, ret); 147 return ret; 148 } 149 } 150 } else if (field->flags & VMS_MUST_EXIST) { 151 error_report("Input validation failed: %s/%s", 152 vmsd->name, field->name); 153 return -1; 154 } 155 field++; 156 } 157 ret = vmstate_subsection_load(f, vmsd, opaque); 158 if (ret != 0) { 159 return ret; 160 } 161 if (vmsd->post_load) { 162 ret = vmsd->post_load(opaque, version_id); 163 } 164 trace_vmstate_load_state_end(vmsd->name, "end", ret); 165 return ret; 166 } 167 168 static int vmfield_name_num(const VMStateField *start, 169 const VMStateField *search) 170 { 171 const VMStateField *field; 172 int found = 0; 173 174 for (field = start; field->name; field++) { 175 if (!strcmp(field->name, search->name)) { 176 if (field == search) { 177 return found; 178 } 179 found++; 180 } 181 } 182 183 return -1; 184 } 185 186 static bool vmfield_name_is_unique(const VMStateField *start, 187 const VMStateField *search) 188 { 189 const VMStateField *field; 190 int found = 0; 191 192 for (field = start; field->name; field++) { 193 if (!strcmp(field->name, search->name)) { 194 found++; 195 /* name found more than once, so it's not unique */ 196 if (found > 1) { 197 return false; 198 } 199 } 200 } 201 202 return true; 203 } 204 205 static const char *vmfield_get_type_name(const VMStateField *field) 206 { 207 const char *type = "unknown"; 208 209 if (field->flags & VMS_STRUCT) { 210 type = "struct"; 211 } else if (field->flags & VMS_VSTRUCT) { 212 type = "vstruct"; 213 } else if (field->info->name) { 214 type = field->info->name; 215 } 216 217 return type; 218 } 219 220 static bool vmsd_can_compress(const VMStateField *field) 221 { 222 if (field->field_exists) { 223 /* Dynamically existing fields mess up compression */ 224 return false; 225 } 226 227 if (field->flags & VMS_STRUCT) { 228 const VMStateField *sfield = field->vmsd->fields; 229 while (sfield->name) { 230 if (!vmsd_can_compress(sfield)) { 231 /* Child elements can't compress, so can't we */ 232 return false; 233 } 234 sfield++; 235 } 236 237 if (field->vmsd->subsections) { 238 /* Subsections may come and go, better don't compress */ 239 return false; 240 } 241 } 242 243 return true; 244 } 245 246 static void vmsd_desc_field_start(const VMStateDescription *vmsd, 247 JSONWriter *vmdesc, 248 const VMStateField *field, int i, int max) 249 { 250 char *name, *old_name; 251 bool is_array = max > 1; 252 bool can_compress = vmsd_can_compress(field); 253 254 if (!vmdesc) { 255 return; 256 } 257 258 name = g_strdup(field->name); 259 260 /* Field name is not unique, need to make it unique */ 261 if (!vmfield_name_is_unique(vmsd->fields, field)) { 262 int num = vmfield_name_num(vmsd->fields, field); 263 old_name = name; 264 name = g_strdup_printf("%s[%d]", name, num); 265 g_free(old_name); 266 } 267 268 json_writer_start_object(vmdesc, NULL); 269 json_writer_str(vmdesc, "name", name); 270 if (is_array) { 271 if (can_compress) { 272 json_writer_int64(vmdesc, "array_len", max); 273 } else { 274 json_writer_int64(vmdesc, "index", i); 275 } 276 } 277 json_writer_str(vmdesc, "type", vmfield_get_type_name(field)); 278 279 if (field->flags & VMS_STRUCT) { 280 json_writer_start_object(vmdesc, "struct"); 281 } 282 283 g_free(name); 284 } 285 286 static void vmsd_desc_field_end(const VMStateDescription *vmsd, 287 JSONWriter *vmdesc, 288 const VMStateField *field, size_t size, int i) 289 { 290 if (!vmdesc) { 291 return; 292 } 293 294 if (field->flags & VMS_STRUCT) { 295 /* We printed a struct in between, close its child object */ 296 json_writer_end_object(vmdesc); 297 } 298 299 json_writer_int64(vmdesc, "size", size); 300 json_writer_end_object(vmdesc); 301 } 302 303 304 bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque) 305 { 306 if (vmsd->needed && !vmsd->needed(opaque)) { 307 /* optional section not needed */ 308 return false; 309 } 310 return true; 311 } 312 313 314 int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd, 315 void *opaque, JSONWriter *vmdesc_id) 316 { 317 return vmstate_save_state_v(f, vmsd, opaque, vmdesc_id, vmsd->version_id); 318 } 319 320 int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd, 321 void *opaque, JSONWriter *vmdesc, int version_id) 322 { 323 int ret = 0; 324 const VMStateField *field = vmsd->fields; 325 326 trace_vmstate_save_state_top(vmsd->name); 327 328 if (vmsd->pre_save) { 329 ret = vmsd->pre_save(opaque); 330 trace_vmstate_save_state_pre_save_res(vmsd->name, ret); 331 if (ret) { 332 error_report("pre-save failed: %s", vmsd->name); 333 return ret; 334 } 335 } 336 337 if (vmdesc) { 338 json_writer_str(vmdesc, "vmsd_name", vmsd->name); 339 json_writer_int64(vmdesc, "version", version_id); 340 json_writer_start_array(vmdesc, "fields"); 341 } 342 343 while (field->name) { 344 if ((field->field_exists && 345 field->field_exists(opaque, version_id)) || 346 (!field->field_exists && 347 field->version_id <= version_id)) { 348 void *first_elem = opaque + field->offset; 349 int i, n_elems = vmstate_n_elems(opaque, field); 350 int size = vmstate_size(opaque, field); 351 int64_t old_offset, written_bytes; 352 JSONWriter *vmdesc_loop = vmdesc; 353 354 trace_vmstate_save_state_loop(vmsd->name, field->name, n_elems); 355 if (field->flags & VMS_POINTER) { 356 first_elem = *(void **)first_elem; 357 assert(first_elem || !n_elems || !size); 358 } 359 for (i = 0; i < n_elems; i++) { 360 void *curr_elem = first_elem + size * i; 361 362 vmsd_desc_field_start(vmsd, vmdesc_loop, field, i, n_elems); 363 old_offset = qemu_file_total_transferred_fast(f); 364 if (field->flags & VMS_ARRAY_OF_POINTER) { 365 assert(curr_elem); 366 curr_elem = *(void **)curr_elem; 367 } 368 if (!curr_elem && size) { 369 /* if null pointer write placeholder and do not follow */ 370 assert(field->flags & VMS_ARRAY_OF_POINTER); 371 ret = vmstate_info_nullptr.put(f, curr_elem, size, NULL, 372 NULL); 373 } else if (field->flags & VMS_STRUCT) { 374 ret = vmstate_save_state(f, field->vmsd, curr_elem, 375 vmdesc_loop); 376 } else if (field->flags & VMS_VSTRUCT) { 377 ret = vmstate_save_state_v(f, field->vmsd, curr_elem, 378 vmdesc_loop, 379 field->struct_version_id); 380 } else { 381 ret = field->info->put(f, curr_elem, size, field, 382 vmdesc_loop); 383 } 384 if (ret) { 385 error_report("Save of field %s/%s failed", 386 vmsd->name, field->name); 387 if (vmsd->post_save) { 388 vmsd->post_save(opaque); 389 } 390 return ret; 391 } 392 393 written_bytes = qemu_file_total_transferred_fast(f) - 394 old_offset; 395 vmsd_desc_field_end(vmsd, vmdesc_loop, field, written_bytes, i); 396 397 /* Compressed arrays only care about the first element */ 398 if (vmdesc_loop && vmsd_can_compress(field)) { 399 vmdesc_loop = NULL; 400 } 401 } 402 } else { 403 if (field->flags & VMS_MUST_EXIST) { 404 error_report("Output state validation failed: %s/%s", 405 vmsd->name, field->name); 406 assert(!(field->flags & VMS_MUST_EXIST)); 407 } 408 } 409 field++; 410 } 411 412 if (vmdesc) { 413 json_writer_end_array(vmdesc); 414 } 415 416 ret = vmstate_subsection_save(f, vmsd, opaque, vmdesc); 417 418 if (vmsd->post_save) { 419 int ps_ret = vmsd->post_save(opaque); 420 if (!ret) { 421 ret = ps_ret; 422 } 423 } 424 return ret; 425 } 426 427 static const VMStateDescription * 428 vmstate_get_subsection(const VMStateDescription **sub, char *idstr) 429 { 430 while (sub && *sub) { 431 if (strcmp(idstr, (*sub)->name) == 0) { 432 return *sub; 433 } 434 sub++; 435 } 436 return NULL; 437 } 438 439 static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, 440 void *opaque) 441 { 442 trace_vmstate_subsection_load(vmsd->name); 443 444 while (qemu_peek_byte(f, 0) == QEMU_VM_SUBSECTION) { 445 char idstr[256], *idstr_ret; 446 int ret; 447 uint8_t version_id, len, size; 448 const VMStateDescription *sub_vmsd; 449 450 len = qemu_peek_byte(f, 1); 451 if (len < strlen(vmsd->name) + 1) { 452 /* subsection name has be be "section_name/a" */ 453 trace_vmstate_subsection_load_bad(vmsd->name, "(short)", ""); 454 return 0; 455 } 456 size = qemu_peek_buffer(f, (uint8_t **)&idstr_ret, len, 2); 457 if (size != len) { 458 trace_vmstate_subsection_load_bad(vmsd->name, "(peek fail)", ""); 459 return 0; 460 } 461 memcpy(idstr, idstr_ret, size); 462 idstr[size] = 0; 463 464 if (strncmp(vmsd->name, idstr, strlen(vmsd->name)) != 0) { 465 trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(prefix)"); 466 /* it doesn't have a valid subsection name */ 467 return 0; 468 } 469 sub_vmsd = vmstate_get_subsection(vmsd->subsections, idstr); 470 if (sub_vmsd == NULL) { 471 trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(lookup)"); 472 return -ENOENT; 473 } 474 qemu_file_skip(f, 1); /* subsection */ 475 qemu_file_skip(f, 1); /* len */ 476 qemu_file_skip(f, len); /* idstr */ 477 version_id = qemu_get_be32(f); 478 479 ret = vmstate_load_state(f, sub_vmsd, opaque, version_id); 480 if (ret) { 481 trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(child)"); 482 return ret; 483 } 484 } 485 486 trace_vmstate_subsection_load_good(vmsd->name); 487 return 0; 488 } 489 490 static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd, 491 void *opaque, JSONWriter *vmdesc) 492 { 493 const VMStateDescription **sub = vmsd->subsections; 494 bool vmdesc_has_subsections = false; 495 int ret = 0; 496 497 trace_vmstate_subsection_save_top(vmsd->name); 498 while (sub && *sub) { 499 if (vmstate_save_needed(*sub, opaque)) { 500 const VMStateDescription *vmsdsub = *sub; 501 uint8_t len; 502 503 trace_vmstate_subsection_save_loop(vmsd->name, vmsdsub->name); 504 if (vmdesc) { 505 /* Only create subsection array when we have any */ 506 if (!vmdesc_has_subsections) { 507 json_writer_start_array(vmdesc, "subsections"); 508 vmdesc_has_subsections = true; 509 } 510 511 json_writer_start_object(vmdesc, NULL); 512 } 513 514 qemu_put_byte(f, QEMU_VM_SUBSECTION); 515 len = strlen(vmsdsub->name); 516 qemu_put_byte(f, len); 517 qemu_put_buffer(f, (uint8_t *)vmsdsub->name, len); 518 qemu_put_be32(f, vmsdsub->version_id); 519 ret = vmstate_save_state(f, vmsdsub, opaque, vmdesc); 520 if (ret) { 521 return ret; 522 } 523 524 if (vmdesc) { 525 json_writer_end_object(vmdesc); 526 } 527 } 528 sub++; 529 } 530 531 if (vmdesc_has_subsections) { 532 json_writer_end_array(vmdesc); 533 } 534 535 return ret; 536 }