xref: /openbmc/qemu/migration/savevm.c (revision b45c03f5)
1 /*
2  * QEMU System Emulator
3  *
4  * Copyright (c) 2003-2008 Fabrice Bellard
5  * Copyright (c) 2009-2015 Red Hat Inc
6  *
7  * Authors:
8  *  Juan Quintela <quintela@redhat.com>
9  *
10  * Permission is hereby granted, free of charge, to any person obtaining a copy
11  * of this software and associated documentation files (the "Software"), to deal
12  * in the Software without restriction, including without limitation the rights
13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14  * copies of the Software, and to permit persons to whom the Software is
15  * furnished to do so, subject to the following conditions:
16  *
17  * The above copyright notice and this permission notice shall be included in
18  * all copies or substantial portions of the Software.
19  *
20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26  * THE SOFTWARE.
27  */
28 
29 #include "config-host.h"
30 #include "qemu-common.h"
31 #include "hw/boards.h"
32 #include "hw/hw.h"
33 #include "hw/qdev.h"
34 #include "net/net.h"
35 #include "monitor/monitor.h"
36 #include "sysemu/sysemu.h"
37 #include "qemu/timer.h"
38 #include "audio/audio.h"
39 #include "migration/migration.h"
40 #include "qapi/qmp/qerror.h"
41 #include "qemu/error-report.h"
42 #include "qemu/sockets.h"
43 #include "qemu/queue.h"
44 #include "sysemu/cpus.h"
45 #include "exec/memory.h"
46 #include "qmp-commands.h"
47 #include "trace.h"
48 #include "qemu/iov.h"
49 #include "block/snapshot.h"
50 #include "block/qapi.h"
51 
52 
53 #ifndef ETH_P_RARP
54 #define ETH_P_RARP 0x8035
55 #endif
56 #define ARP_HTYPE_ETH 0x0001
57 #define ARP_PTYPE_IP 0x0800
58 #define ARP_OP_REQUEST_REV 0x3
59 
60 static bool skip_section_footers;
61 
62 static int announce_self_create(uint8_t *buf,
63                                 uint8_t *mac_addr)
64 {
65     /* Ethernet header. */
66     memset(buf, 0xff, 6);         /* destination MAC addr */
67     memcpy(buf + 6, mac_addr, 6); /* source MAC addr */
68     *(uint16_t *)(buf + 12) = htons(ETH_P_RARP); /* ethertype */
69 
70     /* RARP header. */
71     *(uint16_t *)(buf + 14) = htons(ARP_HTYPE_ETH); /* hardware addr space */
72     *(uint16_t *)(buf + 16) = htons(ARP_PTYPE_IP); /* protocol addr space */
73     *(buf + 18) = 6; /* hardware addr length (ethernet) */
74     *(buf + 19) = 4; /* protocol addr length (IPv4) */
75     *(uint16_t *)(buf + 20) = htons(ARP_OP_REQUEST_REV); /* opcode */
76     memcpy(buf + 22, mac_addr, 6); /* source hw addr */
77     memset(buf + 28, 0x00, 4);     /* source protocol addr */
78     memcpy(buf + 32, mac_addr, 6); /* target hw addr */
79     memset(buf + 38, 0x00, 4);     /* target protocol addr */
80 
81     /* Padding to get up to 60 bytes (ethernet min packet size, minus FCS). */
82     memset(buf + 42, 0x00, 18);
83 
84     return 60; /* len (FCS will be added by hardware) */
85 }
86 
87 static void qemu_announce_self_iter(NICState *nic, void *opaque)
88 {
89     uint8_t buf[60];
90     int len;
91 
92     trace_qemu_announce_self_iter(qemu_ether_ntoa(&nic->conf->macaddr));
93     len = announce_self_create(buf, nic->conf->macaddr.a);
94 
95     qemu_send_packet_raw(qemu_get_queue(nic), buf, len);
96 }
97 
98 
99 static void qemu_announce_self_once(void *opaque)
100 {
101     static int count = SELF_ANNOUNCE_ROUNDS;
102     QEMUTimer *timer = *(QEMUTimer **)opaque;
103 
104     qemu_foreach_nic(qemu_announce_self_iter, NULL);
105 
106     if (--count) {
107         /* delay 50ms, 150ms, 250ms, ... */
108         timer_mod(timer, qemu_clock_get_ms(QEMU_CLOCK_REALTIME) +
109                   self_announce_delay(count));
110     } else {
111             timer_del(timer);
112             timer_free(timer);
113     }
114 }
115 
116 void qemu_announce_self(void)
117 {
118     static QEMUTimer *timer;
119     timer = timer_new_ms(QEMU_CLOCK_REALTIME, qemu_announce_self_once, &timer);
120     qemu_announce_self_once(&timer);
121 }
122 
123 /***********************************************************/
124 /* savevm/loadvm support */
125 
126 static ssize_t block_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
127                                    int64_t pos)
128 {
129     int ret;
130     QEMUIOVector qiov;
131 
132     qemu_iovec_init_external(&qiov, iov, iovcnt);
133     ret = bdrv_writev_vmstate(opaque, &qiov, pos);
134     if (ret < 0) {
135         return ret;
136     }
137 
138     return qiov.size;
139 }
140 
141 static int block_put_buffer(void *opaque, const uint8_t *buf,
142                            int64_t pos, int size)
143 {
144     bdrv_save_vmstate(opaque, buf, pos, size);
145     return size;
146 }
147 
148 static int block_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
149 {
150     return bdrv_load_vmstate(opaque, buf, pos, size);
151 }
152 
153 static int bdrv_fclose(void *opaque)
154 {
155     return bdrv_flush(opaque);
156 }
157 
158 static const QEMUFileOps bdrv_read_ops = {
159     .get_buffer = block_get_buffer,
160     .close =      bdrv_fclose
161 };
162 
163 static const QEMUFileOps bdrv_write_ops = {
164     .put_buffer     = block_put_buffer,
165     .writev_buffer  = block_writev_buffer,
166     .close          = bdrv_fclose
167 };
168 
169 static QEMUFile *qemu_fopen_bdrv(BlockDriverState *bs, int is_writable)
170 {
171     if (is_writable) {
172         return qemu_fopen_ops(bs, &bdrv_write_ops);
173     }
174     return qemu_fopen_ops(bs, &bdrv_read_ops);
175 }
176 
177 
178 /* QEMUFile timer support.
179  * Not in qemu-file.c to not add qemu-timer.c as dependency to qemu-file.c
180  */
181 
182 void timer_put(QEMUFile *f, QEMUTimer *ts)
183 {
184     uint64_t expire_time;
185 
186     expire_time = timer_expire_time_ns(ts);
187     qemu_put_be64(f, expire_time);
188 }
189 
190 void timer_get(QEMUFile *f, QEMUTimer *ts)
191 {
192     uint64_t expire_time;
193 
194     expire_time = qemu_get_be64(f);
195     if (expire_time != -1) {
196         timer_mod_ns(ts, expire_time);
197     } else {
198         timer_del(ts);
199     }
200 }
201 
202 
203 /* VMState timer support.
204  * Not in vmstate.c to not add qemu-timer.c as dependency to vmstate.c
205  */
206 
207 static int get_timer(QEMUFile *f, void *pv, size_t size)
208 {
209     QEMUTimer *v = pv;
210     timer_get(f, v);
211     return 0;
212 }
213 
214 static void put_timer(QEMUFile *f, void *pv, size_t size)
215 {
216     QEMUTimer *v = pv;
217     timer_put(f, v);
218 }
219 
220 const VMStateInfo vmstate_info_timer = {
221     .name = "timer",
222     .get  = get_timer,
223     .put  = put_timer,
224 };
225 
226 
227 typedef struct CompatEntry {
228     char idstr[256];
229     int instance_id;
230 } CompatEntry;
231 
232 typedef struct SaveStateEntry {
233     QTAILQ_ENTRY(SaveStateEntry) entry;
234     char idstr[256];
235     int instance_id;
236     int alias_id;
237     int version_id;
238     int section_id;
239     SaveVMHandlers *ops;
240     const VMStateDescription *vmsd;
241     void *opaque;
242     CompatEntry *compat;
243     int is_ram;
244 } SaveStateEntry;
245 
246 typedef struct SaveState {
247     QTAILQ_HEAD(, SaveStateEntry) handlers;
248     int global_section_id;
249     bool skip_configuration;
250     uint32_t len;
251     const char *name;
252 } SaveState;
253 
254 static SaveState savevm_state = {
255     .handlers = QTAILQ_HEAD_INITIALIZER(savevm_state.handlers),
256     .global_section_id = 0,
257     .skip_configuration = false,
258 };
259 
260 void savevm_skip_configuration(void)
261 {
262     savevm_state.skip_configuration = true;
263 }
264 
265 
266 static void configuration_pre_save(void *opaque)
267 {
268     SaveState *state = opaque;
269     const char *current_name = MACHINE_GET_CLASS(current_machine)->name;
270 
271     state->len = strlen(current_name);
272     state->name = current_name;
273 }
274 
275 static int configuration_post_load(void *opaque, int version_id)
276 {
277     SaveState *state = opaque;
278     const char *current_name = MACHINE_GET_CLASS(current_machine)->name;
279 
280     if (strncmp(state->name, current_name, state->len) != 0) {
281         error_report("Machine type received is '%s' and local is '%s'",
282                      state->name, current_name);
283         return -EINVAL;
284     }
285     return 0;
286 }
287 
288 static const VMStateDescription vmstate_configuration = {
289     .name = "configuration",
290     .version_id = 1,
291     .post_load = configuration_post_load,
292     .pre_save = configuration_pre_save,
293     .fields = (VMStateField[]) {
294         VMSTATE_UINT32(len, SaveState),
295         VMSTATE_VBUFFER_ALLOC_UINT32(name, SaveState, 0, NULL, 0, len),
296         VMSTATE_END_OF_LIST()
297     },
298 };
299 
300 static void dump_vmstate_vmsd(FILE *out_file,
301                               const VMStateDescription *vmsd, int indent,
302                               bool is_subsection);
303 
304 static void dump_vmstate_vmsf(FILE *out_file, const VMStateField *field,
305                               int indent)
306 {
307     fprintf(out_file, "%*s{\n", indent, "");
308     indent += 2;
309     fprintf(out_file, "%*s\"field\": \"%s\",\n", indent, "", field->name);
310     fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "",
311             field->version_id);
312     fprintf(out_file, "%*s\"field_exists\": %s,\n", indent, "",
313             field->field_exists ? "true" : "false");
314     fprintf(out_file, "%*s\"size\": %zu", indent, "", field->size);
315     if (field->vmsd != NULL) {
316         fprintf(out_file, ",\n");
317         dump_vmstate_vmsd(out_file, field->vmsd, indent, false);
318     }
319     fprintf(out_file, "\n%*s}", indent - 2, "");
320 }
321 
322 static void dump_vmstate_vmss(FILE *out_file,
323                               const VMStateDescription **subsection,
324                               int indent)
325 {
326     if (*subsection != NULL) {
327         dump_vmstate_vmsd(out_file, *subsection, indent, true);
328     }
329 }
330 
331 static void dump_vmstate_vmsd(FILE *out_file,
332                               const VMStateDescription *vmsd, int indent,
333                               bool is_subsection)
334 {
335     if (is_subsection) {
336         fprintf(out_file, "%*s{\n", indent, "");
337     } else {
338         fprintf(out_file, "%*s\"%s\": {\n", indent, "", "Description");
339     }
340     indent += 2;
341     fprintf(out_file, "%*s\"name\": \"%s\",\n", indent, "", vmsd->name);
342     fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "",
343             vmsd->version_id);
344     fprintf(out_file, "%*s\"minimum_version_id\": %d", indent, "",
345             vmsd->minimum_version_id);
346     if (vmsd->fields != NULL) {
347         const VMStateField *field = vmsd->fields;
348         bool first;
349 
350         fprintf(out_file, ",\n%*s\"Fields\": [\n", indent, "");
351         first = true;
352         while (field->name != NULL) {
353             if (field->flags & VMS_MUST_EXIST) {
354                 /* Ignore VMSTATE_VALIDATE bits; these don't get migrated */
355                 field++;
356                 continue;
357             }
358             if (!first) {
359                 fprintf(out_file, ",\n");
360             }
361             dump_vmstate_vmsf(out_file, field, indent + 2);
362             field++;
363             first = false;
364         }
365         fprintf(out_file, "\n%*s]", indent, "");
366     }
367     if (vmsd->subsections != NULL) {
368         const VMStateDescription **subsection = vmsd->subsections;
369         bool first;
370 
371         fprintf(out_file, ",\n%*s\"Subsections\": [\n", indent, "");
372         first = true;
373         while (*subsection != NULL) {
374             if (!first) {
375                 fprintf(out_file, ",\n");
376             }
377             dump_vmstate_vmss(out_file, subsection, indent + 2);
378             subsection++;
379             first = false;
380         }
381         fprintf(out_file, "\n%*s]", indent, "");
382     }
383     fprintf(out_file, "\n%*s}", indent - 2, "");
384 }
385 
386 static void dump_machine_type(FILE *out_file)
387 {
388     MachineClass *mc;
389 
390     mc = MACHINE_GET_CLASS(current_machine);
391 
392     fprintf(out_file, "  \"vmschkmachine\": {\n");
393     fprintf(out_file, "    \"Name\": \"%s\"\n", mc->name);
394     fprintf(out_file, "  },\n");
395 }
396 
397 void dump_vmstate_json_to_file(FILE *out_file)
398 {
399     GSList *list, *elt;
400     bool first;
401 
402     fprintf(out_file, "{\n");
403     dump_machine_type(out_file);
404 
405     first = true;
406     list = object_class_get_list(TYPE_DEVICE, true);
407     for (elt = list; elt; elt = elt->next) {
408         DeviceClass *dc = OBJECT_CLASS_CHECK(DeviceClass, elt->data,
409                                              TYPE_DEVICE);
410         const char *name;
411         int indent = 2;
412 
413         if (!dc->vmsd) {
414             continue;
415         }
416 
417         if (!first) {
418             fprintf(out_file, ",\n");
419         }
420         name = object_class_get_name(OBJECT_CLASS(dc));
421         fprintf(out_file, "%*s\"%s\": {\n", indent, "", name);
422         indent += 2;
423         fprintf(out_file, "%*s\"Name\": \"%s\",\n", indent, "", name);
424         fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "",
425                 dc->vmsd->version_id);
426         fprintf(out_file, "%*s\"minimum_version_id\": %d,\n", indent, "",
427                 dc->vmsd->minimum_version_id);
428 
429         dump_vmstate_vmsd(out_file, dc->vmsd, indent, false);
430 
431         fprintf(out_file, "\n%*s}", indent - 2, "");
432         first = false;
433     }
434     fprintf(out_file, "\n}\n");
435     fclose(out_file);
436 }
437 
438 static int calculate_new_instance_id(const char *idstr)
439 {
440     SaveStateEntry *se;
441     int instance_id = 0;
442 
443     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
444         if (strcmp(idstr, se->idstr) == 0
445             && instance_id <= se->instance_id) {
446             instance_id = se->instance_id + 1;
447         }
448     }
449     return instance_id;
450 }
451 
452 static int calculate_compat_instance_id(const char *idstr)
453 {
454     SaveStateEntry *se;
455     int instance_id = 0;
456 
457     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
458         if (!se->compat) {
459             continue;
460         }
461 
462         if (strcmp(idstr, se->compat->idstr) == 0
463             && instance_id <= se->compat->instance_id) {
464             instance_id = se->compat->instance_id + 1;
465         }
466     }
467     return instance_id;
468 }
469 
470 /* TODO: Individual devices generally have very little idea about the rest
471    of the system, so instance_id should be removed/replaced.
472    Meanwhile pass -1 as instance_id if you do not already have a clearly
473    distinguishing id for all instances of your device class. */
474 int register_savevm_live(DeviceState *dev,
475                          const char *idstr,
476                          int instance_id,
477                          int version_id,
478                          SaveVMHandlers *ops,
479                          void *opaque)
480 {
481     SaveStateEntry *se;
482 
483     se = g_malloc0(sizeof(SaveStateEntry));
484     se->version_id = version_id;
485     se->section_id = savevm_state.global_section_id++;
486     se->ops = ops;
487     se->opaque = opaque;
488     se->vmsd = NULL;
489     /* if this is a live_savem then set is_ram */
490     if (ops->save_live_setup != NULL) {
491         se->is_ram = 1;
492     }
493 
494     if (dev) {
495         char *id = qdev_get_dev_path(dev);
496         if (id) {
497             pstrcpy(se->idstr, sizeof(se->idstr), id);
498             pstrcat(se->idstr, sizeof(se->idstr), "/");
499             g_free(id);
500 
501             se->compat = g_malloc0(sizeof(CompatEntry));
502             pstrcpy(se->compat->idstr, sizeof(se->compat->idstr), idstr);
503             se->compat->instance_id = instance_id == -1 ?
504                          calculate_compat_instance_id(idstr) : instance_id;
505             instance_id = -1;
506         }
507     }
508     pstrcat(se->idstr, sizeof(se->idstr), idstr);
509 
510     if (instance_id == -1) {
511         se->instance_id = calculate_new_instance_id(se->idstr);
512     } else {
513         se->instance_id = instance_id;
514     }
515     assert(!se->compat || se->instance_id == 0);
516     /* add at the end of list */
517     QTAILQ_INSERT_TAIL(&savevm_state.handlers, se, entry);
518     return 0;
519 }
520 
521 int register_savevm(DeviceState *dev,
522                     const char *idstr,
523                     int instance_id,
524                     int version_id,
525                     SaveStateHandler *save_state,
526                     LoadStateHandler *load_state,
527                     void *opaque)
528 {
529     SaveVMHandlers *ops = g_malloc0(sizeof(SaveVMHandlers));
530     ops->save_state = save_state;
531     ops->load_state = load_state;
532     return register_savevm_live(dev, idstr, instance_id, version_id,
533                                 ops, opaque);
534 }
535 
536 void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque)
537 {
538     SaveStateEntry *se, *new_se;
539     char id[256] = "";
540 
541     if (dev) {
542         char *path = qdev_get_dev_path(dev);
543         if (path) {
544             pstrcpy(id, sizeof(id), path);
545             pstrcat(id, sizeof(id), "/");
546             g_free(path);
547         }
548     }
549     pstrcat(id, sizeof(id), idstr);
550 
551     QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) {
552         if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) {
553             QTAILQ_REMOVE(&savevm_state.handlers, se, entry);
554             if (se->compat) {
555                 g_free(se->compat);
556             }
557             g_free(se->ops);
558             g_free(se);
559         }
560     }
561 }
562 
563 int vmstate_register_with_alias_id(DeviceState *dev, int instance_id,
564                                    const VMStateDescription *vmsd,
565                                    void *opaque, int alias_id,
566                                    int required_for_version)
567 {
568     SaveStateEntry *se;
569 
570     /* If this triggers, alias support can be dropped for the vmsd. */
571     assert(alias_id == -1 || required_for_version >= vmsd->minimum_version_id);
572 
573     se = g_malloc0(sizeof(SaveStateEntry));
574     se->version_id = vmsd->version_id;
575     se->section_id = savevm_state.global_section_id++;
576     se->opaque = opaque;
577     se->vmsd = vmsd;
578     se->alias_id = alias_id;
579 
580     if (dev) {
581         char *id = qdev_get_dev_path(dev);
582         if (id) {
583             pstrcpy(se->idstr, sizeof(se->idstr), id);
584             pstrcat(se->idstr, sizeof(se->idstr), "/");
585             g_free(id);
586 
587             se->compat = g_malloc0(sizeof(CompatEntry));
588             pstrcpy(se->compat->idstr, sizeof(se->compat->idstr), vmsd->name);
589             se->compat->instance_id = instance_id == -1 ?
590                          calculate_compat_instance_id(vmsd->name) : instance_id;
591             instance_id = -1;
592         }
593     }
594     pstrcat(se->idstr, sizeof(se->idstr), vmsd->name);
595 
596     if (instance_id == -1) {
597         se->instance_id = calculate_new_instance_id(se->idstr);
598     } else {
599         se->instance_id = instance_id;
600     }
601     assert(!se->compat || se->instance_id == 0);
602     /* add at the end of list */
603     QTAILQ_INSERT_TAIL(&savevm_state.handlers, se, entry);
604     return 0;
605 }
606 
607 void vmstate_unregister(DeviceState *dev, const VMStateDescription *vmsd,
608                         void *opaque)
609 {
610     SaveStateEntry *se, *new_se;
611 
612     QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) {
613         if (se->vmsd == vmsd && se->opaque == opaque) {
614             QTAILQ_REMOVE(&savevm_state.handlers, se, entry);
615             if (se->compat) {
616                 g_free(se->compat);
617             }
618             g_free(se);
619         }
620     }
621 }
622 
623 static int vmstate_load(QEMUFile *f, SaveStateEntry *se, int version_id)
624 {
625     trace_vmstate_load(se->idstr, se->vmsd ? se->vmsd->name : "(old)");
626     if (!se->vmsd) {         /* Old style */
627         return se->ops->load_state(f, se->opaque, version_id);
628     }
629     return vmstate_load_state(f, se->vmsd, se->opaque, version_id);
630 }
631 
632 static void vmstate_save_old_style(QEMUFile *f, SaveStateEntry *se, QJSON *vmdesc)
633 {
634     int64_t old_offset, size;
635 
636     old_offset = qemu_ftell_fast(f);
637     se->ops->save_state(f, se->opaque);
638     size = qemu_ftell_fast(f) - old_offset;
639 
640     if (vmdesc) {
641         json_prop_int(vmdesc, "size", size);
642         json_start_array(vmdesc, "fields");
643         json_start_object(vmdesc, NULL);
644         json_prop_str(vmdesc, "name", "data");
645         json_prop_int(vmdesc, "size", size);
646         json_prop_str(vmdesc, "type", "buffer");
647         json_end_object(vmdesc);
648         json_end_array(vmdesc);
649     }
650 }
651 
652 static void vmstate_save(QEMUFile *f, SaveStateEntry *se, QJSON *vmdesc)
653 {
654     trace_vmstate_save(se->idstr, se->vmsd ? se->vmsd->name : "(old)");
655     if (!se->vmsd) {
656         vmstate_save_old_style(f, se, vmdesc);
657         return;
658     }
659     vmstate_save_state(f, se->vmsd, se->opaque, vmdesc);
660 }
661 
662 void savevm_skip_section_footers(void)
663 {
664     skip_section_footers = true;
665 }
666 
667 /*
668  * Write the header for device section (QEMU_VM_SECTION START/END/PART/FULL)
669  */
670 static void save_section_header(QEMUFile *f, SaveStateEntry *se,
671                                 uint8_t section_type)
672 {
673     qemu_put_byte(f, section_type);
674     qemu_put_be32(f, se->section_id);
675 
676     if (section_type == QEMU_VM_SECTION_FULL ||
677         section_type == QEMU_VM_SECTION_START) {
678         /* ID string */
679         size_t len = strlen(se->idstr);
680         qemu_put_byte(f, len);
681         qemu_put_buffer(f, (uint8_t *)se->idstr, len);
682 
683         qemu_put_be32(f, se->instance_id);
684         qemu_put_be32(f, se->version_id);
685     }
686 }
687 
688 /*
689  * Write a footer onto device sections that catches cases misformatted device
690  * sections.
691  */
692 static void save_section_footer(QEMUFile *f, SaveStateEntry *se)
693 {
694     if (!skip_section_footers) {
695         qemu_put_byte(f, QEMU_VM_SECTION_FOOTER);
696         qemu_put_be32(f, se->section_id);
697     }
698 }
699 
700 bool qemu_savevm_state_blocked(Error **errp)
701 {
702     SaveStateEntry *se;
703 
704     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
705         if (se->vmsd && se->vmsd->unmigratable) {
706             error_setg(errp, "State blocked by non-migratable device '%s'",
707                        se->idstr);
708             return true;
709         }
710     }
711     return false;
712 }
713 
714 void qemu_savevm_state_header(QEMUFile *f)
715 {
716     trace_savevm_state_header();
717     qemu_put_be32(f, QEMU_VM_FILE_MAGIC);
718     qemu_put_be32(f, QEMU_VM_FILE_VERSION);
719 }
720 
721 void qemu_savevm_state_begin(QEMUFile *f,
722                              const MigrationParams *params)
723 {
724     SaveStateEntry *se;
725     int ret;
726 
727     trace_savevm_state_begin();
728     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
729         if (!se->ops || !se->ops->set_params) {
730             continue;
731         }
732         se->ops->set_params(params, se->opaque);
733     }
734 
735     if (!savevm_state.skip_configuration) {
736         qemu_put_byte(f, QEMU_VM_CONFIGURATION);
737         vmstate_save_state(f, &vmstate_configuration, &savevm_state, 0);
738     }
739 
740     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
741         if (!se->ops || !se->ops->save_live_setup) {
742             continue;
743         }
744         if (se->ops && se->ops->is_active) {
745             if (!se->ops->is_active(se->opaque)) {
746                 continue;
747             }
748         }
749         save_section_header(f, se, QEMU_VM_SECTION_START);
750 
751         ret = se->ops->save_live_setup(f, se->opaque);
752         save_section_footer(f, se);
753         if (ret < 0) {
754             qemu_file_set_error(f, ret);
755             break;
756         }
757     }
758 }
759 
760 /*
761  * this function has three return values:
762  *   negative: there was one error, and we have -errno.
763  *   0 : We haven't finished, caller have to go again
764  *   1 : We have finished, we can go to complete phase
765  */
766 int qemu_savevm_state_iterate(QEMUFile *f)
767 {
768     SaveStateEntry *se;
769     int ret = 1;
770 
771     trace_savevm_state_iterate();
772     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
773         if (!se->ops || !se->ops->save_live_iterate) {
774             continue;
775         }
776         if (se->ops && se->ops->is_active) {
777             if (!se->ops->is_active(se->opaque)) {
778                 continue;
779             }
780         }
781         if (qemu_file_rate_limit(f)) {
782             return 0;
783         }
784         trace_savevm_section_start(se->idstr, se->section_id);
785 
786         save_section_header(f, se, QEMU_VM_SECTION_PART);
787 
788         ret = se->ops->save_live_iterate(f, se->opaque);
789         trace_savevm_section_end(se->idstr, se->section_id, ret);
790         save_section_footer(f, se);
791 
792         if (ret < 0) {
793             qemu_file_set_error(f, ret);
794         }
795         if (ret <= 0) {
796             /* Do not proceed to the next vmstate before this one reported
797                completion of the current stage. This serializes the migration
798                and reduces the probability that a faster changing state is
799                synchronized over and over again. */
800             break;
801         }
802     }
803     return ret;
804 }
805 
806 static bool should_send_vmdesc(void)
807 {
808     MachineState *machine = MACHINE(qdev_get_machine());
809     return !machine->suppress_vmdesc;
810 }
811 
812 void qemu_savevm_state_complete(QEMUFile *f)
813 {
814     QJSON *vmdesc;
815     int vmdesc_len;
816     SaveStateEntry *se;
817     int ret;
818 
819     trace_savevm_state_complete();
820 
821     cpu_synchronize_all_states();
822 
823     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
824         if (!se->ops || !se->ops->save_live_complete) {
825             continue;
826         }
827         if (se->ops && se->ops->is_active) {
828             if (!se->ops->is_active(se->opaque)) {
829                 continue;
830             }
831         }
832         trace_savevm_section_start(se->idstr, se->section_id);
833 
834         save_section_header(f, se, QEMU_VM_SECTION_END);
835 
836         ret = se->ops->save_live_complete(f, se->opaque);
837         trace_savevm_section_end(se->idstr, se->section_id, ret);
838         save_section_footer(f, se);
839         if (ret < 0) {
840             qemu_file_set_error(f, ret);
841             return;
842         }
843     }
844 
845     vmdesc = qjson_new();
846     json_prop_int(vmdesc, "page_size", TARGET_PAGE_SIZE);
847     json_start_array(vmdesc, "devices");
848     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
849 
850         if ((!se->ops || !se->ops->save_state) && !se->vmsd) {
851             continue;
852         }
853         if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) {
854             trace_savevm_section_skip(se->idstr, se->section_id);
855             continue;
856         }
857 
858         trace_savevm_section_start(se->idstr, se->section_id);
859 
860         json_start_object(vmdesc, NULL);
861         json_prop_str(vmdesc, "name", se->idstr);
862         json_prop_int(vmdesc, "instance_id", se->instance_id);
863 
864         save_section_header(f, se, QEMU_VM_SECTION_FULL);
865 
866         vmstate_save(f, se, vmdesc);
867 
868         json_end_object(vmdesc);
869         trace_savevm_section_end(se->idstr, se->section_id, 0);
870         save_section_footer(f, se);
871     }
872 
873     qemu_put_byte(f, QEMU_VM_EOF);
874 
875     json_end_array(vmdesc);
876     qjson_finish(vmdesc);
877     vmdesc_len = strlen(qjson_get_str(vmdesc));
878 
879     if (should_send_vmdesc()) {
880         qemu_put_byte(f, QEMU_VM_VMDESCRIPTION);
881         qemu_put_be32(f, vmdesc_len);
882         qemu_put_buffer(f, (uint8_t *)qjson_get_str(vmdesc), vmdesc_len);
883     }
884     object_unref(OBJECT(vmdesc));
885 
886     qemu_fflush(f);
887 }
888 
889 uint64_t qemu_savevm_state_pending(QEMUFile *f, uint64_t max_size)
890 {
891     SaveStateEntry *se;
892     uint64_t ret = 0;
893 
894     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
895         if (!se->ops || !se->ops->save_live_pending) {
896             continue;
897         }
898         if (se->ops && se->ops->is_active) {
899             if (!se->ops->is_active(se->opaque)) {
900                 continue;
901             }
902         }
903         ret += se->ops->save_live_pending(f, se->opaque, max_size);
904     }
905     return ret;
906 }
907 
908 void qemu_savevm_state_cancel(void)
909 {
910     SaveStateEntry *se;
911 
912     trace_savevm_state_cancel();
913     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
914         if (se->ops && se->ops->cancel) {
915             se->ops->cancel(se->opaque);
916         }
917     }
918 }
919 
920 static int qemu_savevm_state(QEMUFile *f, Error **errp)
921 {
922     int ret;
923     MigrationParams params = {
924         .blk = 0,
925         .shared = 0
926     };
927 
928     if (qemu_savevm_state_blocked(errp)) {
929         return -EINVAL;
930     }
931 
932     qemu_mutex_unlock_iothread();
933     qemu_savevm_state_header(f);
934     qemu_savevm_state_begin(f, &params);
935     qemu_mutex_lock_iothread();
936 
937     while (qemu_file_get_error(f) == 0) {
938         if (qemu_savevm_state_iterate(f) > 0) {
939             break;
940         }
941     }
942 
943     ret = qemu_file_get_error(f);
944     if (ret == 0) {
945         qemu_savevm_state_complete(f);
946         ret = qemu_file_get_error(f);
947     }
948     if (ret != 0) {
949         qemu_savevm_state_cancel();
950         error_setg_errno(errp, -ret, "Error while writing VM state");
951     }
952     return ret;
953 }
954 
955 static int qemu_save_device_state(QEMUFile *f)
956 {
957     SaveStateEntry *se;
958 
959     qemu_put_be32(f, QEMU_VM_FILE_MAGIC);
960     qemu_put_be32(f, QEMU_VM_FILE_VERSION);
961 
962     cpu_synchronize_all_states();
963 
964     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
965         if (se->is_ram) {
966             continue;
967         }
968         if ((!se->ops || !se->ops->save_state) && !se->vmsd) {
969             continue;
970         }
971         if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) {
972             continue;
973         }
974 
975         save_section_header(f, se, QEMU_VM_SECTION_FULL);
976 
977         vmstate_save(f, se, NULL);
978 
979         save_section_footer(f, se);
980     }
981 
982     qemu_put_byte(f, QEMU_VM_EOF);
983 
984     return qemu_file_get_error(f);
985 }
986 
987 static SaveStateEntry *find_se(const char *idstr, int instance_id)
988 {
989     SaveStateEntry *se;
990 
991     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
992         if (!strcmp(se->idstr, idstr) &&
993             (instance_id == se->instance_id ||
994              instance_id == se->alias_id))
995             return se;
996         /* Migrating from an older version? */
997         if (strstr(se->idstr, idstr) && se->compat) {
998             if (!strcmp(se->compat->idstr, idstr) &&
999                 (instance_id == se->compat->instance_id ||
1000                  instance_id == se->alias_id))
1001                 return se;
1002         }
1003     }
1004     return NULL;
1005 }
1006 
1007 struct LoadStateEntry {
1008     QLIST_ENTRY(LoadStateEntry) entry;
1009     SaveStateEntry *se;
1010     int section_id;
1011     int version_id;
1012 };
1013 
1014 /*
1015  * Read a footer off the wire and check that it matches the expected section
1016  *
1017  * Returns: true if the footer was good
1018  *          false if there is a problem (and calls error_report to say why)
1019  */
1020 static bool check_section_footer(QEMUFile *f, LoadStateEntry *le)
1021 {
1022     uint8_t read_mark;
1023     uint32_t read_section_id;
1024 
1025     if (skip_section_footers) {
1026         /* No footer to check */
1027         return true;
1028     }
1029 
1030     read_mark = qemu_get_byte(f);
1031 
1032     if (read_mark != QEMU_VM_SECTION_FOOTER) {
1033         error_report("Missing section footer for %s", le->se->idstr);
1034         return false;
1035     }
1036 
1037     read_section_id = qemu_get_be32(f);
1038     if (read_section_id != le->section_id) {
1039         error_report("Mismatched section id in footer for %s -"
1040                      " read 0x%x expected 0x%x",
1041                      le->se->idstr, read_section_id, le->section_id);
1042         return false;
1043     }
1044 
1045     /* All good */
1046     return true;
1047 }
1048 
1049 void loadvm_free_handlers(MigrationIncomingState *mis)
1050 {
1051     LoadStateEntry *le, *new_le;
1052 
1053     QLIST_FOREACH_SAFE(le, &mis->loadvm_handlers, entry, new_le) {
1054         QLIST_REMOVE(le, entry);
1055         g_free(le);
1056     }
1057 }
1058 
1059 int qemu_loadvm_state(QEMUFile *f)
1060 {
1061     MigrationIncomingState *mis = migration_incoming_get_current();
1062     Error *local_err = NULL;
1063     uint8_t section_type;
1064     unsigned int v;
1065     int ret;
1066     int file_error_after_eof = -1;
1067 
1068     if (qemu_savevm_state_blocked(&local_err)) {
1069         error_report_err(local_err);
1070         return -EINVAL;
1071     }
1072 
1073     v = qemu_get_be32(f);
1074     if (v != QEMU_VM_FILE_MAGIC) {
1075         error_report("Not a migration stream");
1076         return -EINVAL;
1077     }
1078 
1079     v = qemu_get_be32(f);
1080     if (v == QEMU_VM_FILE_VERSION_COMPAT) {
1081         error_report("SaveVM v2 format is obsolete and don't work anymore");
1082         return -ENOTSUP;
1083     }
1084     if (v != QEMU_VM_FILE_VERSION) {
1085         error_report("Unsupported migration stream version");
1086         return -ENOTSUP;
1087     }
1088 
1089     if (!savevm_state.skip_configuration) {
1090         if (qemu_get_byte(f) != QEMU_VM_CONFIGURATION) {
1091             error_report("Configuration section missing");
1092             return -EINVAL;
1093         }
1094         ret = vmstate_load_state(f, &vmstate_configuration, &savevm_state, 0);
1095 
1096         if (ret) {
1097             return ret;
1098         }
1099     }
1100 
1101     while ((section_type = qemu_get_byte(f)) != QEMU_VM_EOF) {
1102         uint32_t instance_id, version_id, section_id;
1103         SaveStateEntry *se;
1104         LoadStateEntry *le;
1105         char idstr[256];
1106 
1107         trace_qemu_loadvm_state_section(section_type);
1108         switch (section_type) {
1109         case QEMU_VM_SECTION_START:
1110         case QEMU_VM_SECTION_FULL:
1111             /* Read section start */
1112             section_id = qemu_get_be32(f);
1113             if (!qemu_get_counted_string(f, idstr)) {
1114                 error_report("Unable to read ID string for section %u",
1115                             section_id);
1116                 return -EINVAL;
1117             }
1118             instance_id = qemu_get_be32(f);
1119             version_id = qemu_get_be32(f);
1120 
1121             trace_qemu_loadvm_state_section_startfull(section_id, idstr,
1122                                                       instance_id, version_id);
1123             /* Find savevm section */
1124             se = find_se(idstr, instance_id);
1125             if (se == NULL) {
1126                 error_report("Unknown savevm section or instance '%s' %d",
1127                              idstr, instance_id);
1128                 ret = -EINVAL;
1129                 goto out;
1130             }
1131 
1132             /* Validate version */
1133             if (version_id > se->version_id) {
1134                 error_report("savevm: unsupported version %d for '%s' v%d",
1135                              version_id, idstr, se->version_id);
1136                 ret = -EINVAL;
1137                 goto out;
1138             }
1139 
1140             /* Add entry */
1141             le = g_malloc0(sizeof(*le));
1142 
1143             le->se = se;
1144             le->section_id = section_id;
1145             le->version_id = version_id;
1146             QLIST_INSERT_HEAD(&mis->loadvm_handlers, le, entry);
1147 
1148             ret = vmstate_load(f, le->se, le->version_id);
1149             if (ret < 0) {
1150                 error_report("error while loading state for instance 0x%x of"
1151                              " device '%s'", instance_id, idstr);
1152                 goto out;
1153             }
1154             if (!check_section_footer(f, le)) {
1155                 ret = -EINVAL;
1156                 goto out;
1157             }
1158             break;
1159         case QEMU_VM_SECTION_PART:
1160         case QEMU_VM_SECTION_END:
1161             section_id = qemu_get_be32(f);
1162 
1163             trace_qemu_loadvm_state_section_partend(section_id);
1164             QLIST_FOREACH(le, &mis->loadvm_handlers, entry) {
1165                 if (le->section_id == section_id) {
1166                     break;
1167                 }
1168             }
1169             if (le == NULL) {
1170                 error_report("Unknown savevm section %d", section_id);
1171                 ret = -EINVAL;
1172                 goto out;
1173             }
1174 
1175             ret = vmstate_load(f, le->se, le->version_id);
1176             if (ret < 0) {
1177                 error_report("error while loading state section id %d(%s)",
1178                              section_id, le->se->idstr);
1179                 goto out;
1180             }
1181             if (!check_section_footer(f, le)) {
1182                 ret = -EINVAL;
1183                 goto out;
1184             }
1185             break;
1186         default:
1187             error_report("Unknown savevm section type %d", section_type);
1188             ret = -EINVAL;
1189             goto out;
1190         }
1191     }
1192 
1193     file_error_after_eof = qemu_file_get_error(f);
1194 
1195     /*
1196      * Try to read in the VMDESC section as well, so that dumping tools that
1197      * intercept our migration stream have the chance to see it.
1198      */
1199 
1200     /* We've got to be careful; if we don't read the data and just shut the fd
1201      * then the sender can error if we close while it's still sending.
1202      * We also mustn't read data that isn't there; some transports (RDMA)
1203      * will stall waiting for that data when the source has already closed.
1204      */
1205     if (should_send_vmdesc()) {
1206         uint8_t *buf;
1207         uint32_t size;
1208         section_type = qemu_get_byte(f);
1209 
1210         if (section_type != QEMU_VM_VMDESCRIPTION) {
1211             error_report("Expected vmdescription section, but got %d",
1212                          section_type);
1213             /*
1214              * It doesn't seem worth failing at this point since
1215              * we apparently have an otherwise valid VM state
1216              */
1217         } else {
1218             buf = g_malloc(0x1000);
1219             size = qemu_get_be32(f);
1220 
1221             while (size > 0) {
1222                 uint32_t read_chunk = MIN(size, 0x1000);
1223                 qemu_get_buffer(f, buf, read_chunk);
1224                 size -= read_chunk;
1225             }
1226             g_free(buf);
1227         }
1228     }
1229 
1230     cpu_synchronize_all_post_init();
1231 
1232     ret = 0;
1233 
1234 out:
1235     if (ret == 0) {
1236         /* We may not have a VMDESC section, so ignore relative errors */
1237         ret = file_error_after_eof;
1238     }
1239 
1240     return ret;
1241 }
1242 
1243 static BlockDriverState *find_vmstate_bs(void)
1244 {
1245     BlockDriverState *bs = NULL;
1246     while ((bs = bdrv_next(bs))) {
1247         if (bdrv_can_snapshot(bs)) {
1248             return bs;
1249         }
1250     }
1251     return NULL;
1252 }
1253 
1254 /*
1255  * Deletes snapshots of a given name in all opened images.
1256  */
1257 static int del_existing_snapshots(Monitor *mon, const char *name)
1258 {
1259     BlockDriverState *bs;
1260     QEMUSnapshotInfo sn1, *snapshot = &sn1;
1261     Error *err = NULL;
1262 
1263     bs = NULL;
1264     while ((bs = bdrv_next(bs))) {
1265         if (bdrv_can_snapshot(bs) &&
1266             bdrv_snapshot_find(bs, snapshot, name) >= 0) {
1267             bdrv_snapshot_delete_by_id_or_name(bs, name, &err);
1268             if (err) {
1269                 monitor_printf(mon,
1270                                "Error while deleting snapshot on device '%s':"
1271                                " %s\n",
1272                                bdrv_get_device_name(bs),
1273                                error_get_pretty(err));
1274                 error_free(err);
1275                 return -1;
1276             }
1277         }
1278     }
1279 
1280     return 0;
1281 }
1282 
1283 void hmp_savevm(Monitor *mon, const QDict *qdict)
1284 {
1285     BlockDriverState *bs, *bs1;
1286     QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1;
1287     int ret;
1288     QEMUFile *f;
1289     int saved_vm_running;
1290     uint64_t vm_state_size;
1291     qemu_timeval tv;
1292     struct tm tm;
1293     const char *name = qdict_get_try_str(qdict, "name");
1294     Error *local_err = NULL;
1295 
1296     /* Verify if there is a device that doesn't support snapshots and is writable */
1297     bs = NULL;
1298     while ((bs = bdrv_next(bs))) {
1299 
1300         if (!bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
1301             continue;
1302         }
1303 
1304         if (!bdrv_can_snapshot(bs)) {
1305             monitor_printf(mon, "Device '%s' is writable but does not support snapshots.\n",
1306                                bdrv_get_device_name(bs));
1307             return;
1308         }
1309     }
1310 
1311     bs = find_vmstate_bs();
1312     if (!bs) {
1313         monitor_printf(mon, "No block device can accept snapshots\n");
1314         return;
1315     }
1316 
1317     saved_vm_running = runstate_is_running();
1318 
1319     ret = global_state_store();
1320     if (ret) {
1321         monitor_printf(mon, "Error saving global state\n");
1322         return;
1323     }
1324     vm_stop(RUN_STATE_SAVE_VM);
1325 
1326     memset(sn, 0, sizeof(*sn));
1327 
1328     /* fill auxiliary fields */
1329     qemu_gettimeofday(&tv);
1330     sn->date_sec = tv.tv_sec;
1331     sn->date_nsec = tv.tv_usec * 1000;
1332     sn->vm_clock_nsec = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
1333 
1334     if (name) {
1335         ret = bdrv_snapshot_find(bs, old_sn, name);
1336         if (ret >= 0) {
1337             pstrcpy(sn->name, sizeof(sn->name), old_sn->name);
1338             pstrcpy(sn->id_str, sizeof(sn->id_str), old_sn->id_str);
1339         } else {
1340             pstrcpy(sn->name, sizeof(sn->name), name);
1341         }
1342     } else {
1343         /* cast below needed for OpenBSD where tv_sec is still 'long' */
1344         localtime_r((const time_t *)&tv.tv_sec, &tm);
1345         strftime(sn->name, sizeof(sn->name), "vm-%Y%m%d%H%M%S", &tm);
1346     }
1347 
1348     /* Delete old snapshots of the same name */
1349     if (name && del_existing_snapshots(mon, name) < 0) {
1350         goto the_end;
1351     }
1352 
1353     /* save the VM state */
1354     f = qemu_fopen_bdrv(bs, 1);
1355     if (!f) {
1356         monitor_printf(mon, "Could not open VM state file\n");
1357         goto the_end;
1358     }
1359     ret = qemu_savevm_state(f, &local_err);
1360     vm_state_size = qemu_ftell(f);
1361     qemu_fclose(f);
1362     if (ret < 0) {
1363         monitor_printf(mon, "%s\n", error_get_pretty(local_err));
1364         error_free(local_err);
1365         goto the_end;
1366     }
1367 
1368     /* create the snapshots */
1369 
1370     bs1 = NULL;
1371     while ((bs1 = bdrv_next(bs1))) {
1372         if (bdrv_can_snapshot(bs1)) {
1373             /* Write VM state size only to the image that contains the state */
1374             sn->vm_state_size = (bs == bs1 ? vm_state_size : 0);
1375             ret = bdrv_snapshot_create(bs1, sn);
1376             if (ret < 0) {
1377                 monitor_printf(mon, "Error while creating snapshot on '%s'\n",
1378                                bdrv_get_device_name(bs1));
1379             }
1380         }
1381     }
1382 
1383  the_end:
1384     if (saved_vm_running) {
1385         vm_start();
1386     }
1387 }
1388 
1389 void qmp_xen_save_devices_state(const char *filename, Error **errp)
1390 {
1391     QEMUFile *f;
1392     int saved_vm_running;
1393     int ret;
1394 
1395     saved_vm_running = runstate_is_running();
1396     vm_stop(RUN_STATE_SAVE_VM);
1397     global_state_store_running();
1398 
1399     f = qemu_fopen(filename, "wb");
1400     if (!f) {
1401         error_setg_file_open(errp, errno, filename);
1402         goto the_end;
1403     }
1404     ret = qemu_save_device_state(f);
1405     qemu_fclose(f);
1406     if (ret < 0) {
1407         error_setg(errp, QERR_IO_ERROR);
1408     }
1409 
1410  the_end:
1411     if (saved_vm_running) {
1412         vm_start();
1413     }
1414 }
1415 
1416 int load_vmstate(const char *name)
1417 {
1418     BlockDriverState *bs, *bs_vm_state;
1419     QEMUSnapshotInfo sn;
1420     QEMUFile *f;
1421     int ret;
1422 
1423     bs_vm_state = find_vmstate_bs();
1424     if (!bs_vm_state) {
1425         error_report("No block device supports snapshots");
1426         return -ENOTSUP;
1427     }
1428 
1429     /* Don't even try to load empty VM states */
1430     ret = bdrv_snapshot_find(bs_vm_state, &sn, name);
1431     if (ret < 0) {
1432         return ret;
1433     } else if (sn.vm_state_size == 0) {
1434         error_report("This is a disk-only snapshot. Revert to it offline "
1435             "using qemu-img.");
1436         return -EINVAL;
1437     }
1438 
1439     /* Verify if there is any device that doesn't support snapshots and is
1440     writable and check if the requested snapshot is available too. */
1441     bs = NULL;
1442     while ((bs = bdrv_next(bs))) {
1443 
1444         if (!bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
1445             continue;
1446         }
1447 
1448         if (!bdrv_can_snapshot(bs)) {
1449             error_report("Device '%s' is writable but does not support snapshots.",
1450                                bdrv_get_device_name(bs));
1451             return -ENOTSUP;
1452         }
1453 
1454         ret = bdrv_snapshot_find(bs, &sn, name);
1455         if (ret < 0) {
1456             error_report("Device '%s' does not have the requested snapshot '%s'",
1457                            bdrv_get_device_name(bs), name);
1458             return ret;
1459         }
1460     }
1461 
1462     /* Flush all IO requests so they don't interfere with the new state.  */
1463     bdrv_drain_all();
1464 
1465     bs = NULL;
1466     while ((bs = bdrv_next(bs))) {
1467         if (bdrv_can_snapshot(bs)) {
1468             ret = bdrv_snapshot_goto(bs, name);
1469             if (ret < 0) {
1470                 error_report("Error %d while activating snapshot '%s' on '%s'",
1471                              ret, name, bdrv_get_device_name(bs));
1472                 return ret;
1473             }
1474         }
1475     }
1476 
1477     /* restore the VM state */
1478     f = qemu_fopen_bdrv(bs_vm_state, 0);
1479     if (!f) {
1480         error_report("Could not open VM state file");
1481         return -EINVAL;
1482     }
1483 
1484     qemu_system_reset(VMRESET_SILENT);
1485     migration_incoming_state_new(f);
1486     ret = qemu_loadvm_state(f);
1487 
1488     qemu_fclose(f);
1489     migration_incoming_state_destroy();
1490     if (ret < 0) {
1491         error_report("Error %d while loading VM state", ret);
1492         return ret;
1493     }
1494 
1495     return 0;
1496 }
1497 
1498 void hmp_delvm(Monitor *mon, const QDict *qdict)
1499 {
1500     BlockDriverState *bs;
1501     Error *err;
1502     const char *name = qdict_get_str(qdict, "name");
1503 
1504     if (!find_vmstate_bs()) {
1505         monitor_printf(mon, "No block device supports snapshots\n");
1506         return;
1507     }
1508 
1509     bs = NULL;
1510     while ((bs = bdrv_next(bs))) {
1511         if (bdrv_can_snapshot(bs)) {
1512             err = NULL;
1513             bdrv_snapshot_delete_by_id_or_name(bs, name, &err);
1514             if (err) {
1515                 monitor_printf(mon,
1516                                "Error while deleting snapshot on device '%s':"
1517                                " %s\n",
1518                                bdrv_get_device_name(bs),
1519                                error_get_pretty(err));
1520                 error_free(err);
1521             }
1522         }
1523     }
1524 }
1525 
1526 void hmp_info_snapshots(Monitor *mon, const QDict *qdict)
1527 {
1528     BlockDriverState *bs, *bs1;
1529     QEMUSnapshotInfo *sn_tab, *sn, s, *sn_info = &s;
1530     int nb_sns, i, ret, available;
1531     int total;
1532     int *available_snapshots;
1533 
1534     bs = find_vmstate_bs();
1535     if (!bs) {
1536         monitor_printf(mon, "No available block device supports snapshots\n");
1537         return;
1538     }
1539 
1540     nb_sns = bdrv_snapshot_list(bs, &sn_tab);
1541     if (nb_sns < 0) {
1542         monitor_printf(mon, "bdrv_snapshot_list: error %d\n", nb_sns);
1543         return;
1544     }
1545 
1546     if (nb_sns == 0) {
1547         monitor_printf(mon, "There is no snapshot available.\n");
1548         return;
1549     }
1550 
1551     available_snapshots = g_malloc0(sizeof(int) * nb_sns);
1552     total = 0;
1553     for (i = 0; i < nb_sns; i++) {
1554         sn = &sn_tab[i];
1555         available = 1;
1556         bs1 = NULL;
1557 
1558         while ((bs1 = bdrv_next(bs1))) {
1559             if (bdrv_can_snapshot(bs1) && bs1 != bs) {
1560                 ret = bdrv_snapshot_find(bs1, sn_info, sn->id_str);
1561                 if (ret < 0) {
1562                     available = 0;
1563                     break;
1564                 }
1565             }
1566         }
1567 
1568         if (available) {
1569             available_snapshots[total] = i;
1570             total++;
1571         }
1572     }
1573 
1574     if (total > 0) {
1575         bdrv_snapshot_dump((fprintf_function)monitor_printf, mon, NULL);
1576         monitor_printf(mon, "\n");
1577         for (i = 0; i < total; i++) {
1578             sn = &sn_tab[available_snapshots[i]];
1579             bdrv_snapshot_dump((fprintf_function)monitor_printf, mon, sn);
1580             monitor_printf(mon, "\n");
1581         }
1582     } else {
1583         monitor_printf(mon, "There is no suitable snapshot available\n");
1584     }
1585 
1586     g_free(sn_tab);
1587     g_free(available_snapshots);
1588 
1589 }
1590 
1591 void vmstate_register_ram(MemoryRegion *mr, DeviceState *dev)
1592 {
1593     qemu_ram_set_idstr(memory_region_get_ram_addr(mr) & TARGET_PAGE_MASK,
1594                        memory_region_name(mr), dev);
1595 }
1596 
1597 void vmstate_unregister_ram(MemoryRegion *mr, DeviceState *dev)
1598 {
1599     qemu_ram_unset_idstr(memory_region_get_ram_addr(mr) & TARGET_PAGE_MASK);
1600 }
1601 
1602 void vmstate_register_ram_global(MemoryRegion *mr)
1603 {
1604     vmstate_register_ram(mr, NULL);
1605 }
1606