aboutsummaryrefslogtreecommitdiff
path: root/dump.c
blob: c812cfaf2d14a64ee836fd7479f9b9ce513bc202 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
/*
 * QEMU dump
 *
 * Copyright Fujitsu, Corp. 2011, 2012
 *
 * Authors:
 *     Wen Congyang <wency@cn.fujitsu.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 *
 */

#include "qemu-common.h"
#include "elf.h"
#include "cpu.h"
#include "exec/cpu-all.h"
#include "exec/hwaddr.h"
#include "monitor/monitor.h"
#include "sysemu/kvm.h"
#include "sysemu/dump.h"
#include "sysemu/sysemu.h"
#include "sysemu/memory_mapping.h"
#include "sysemu/cpus.h"
#include "qapi/error.h"
#include "qmp-commands.h"

static uint16_t cpu_convert_to_target16(uint16_t val, int endian)
{
    if (endian == ELFDATA2LSB) {
        val = cpu_to_le16(val);
    } else {
        val = cpu_to_be16(val);
    }

    return val;
}

static uint32_t cpu_convert_to_target32(uint32_t val, int endian)
{
    if (endian == ELFDATA2LSB) {
        val = cpu_to_le32(val);
    } else {
        val = cpu_to_be32(val);
    }

    return val;
}

static uint64_t cpu_convert_to_target64(uint64_t val, int endian)
{
    if (endian == ELFDATA2LSB) {
        val = cpu_to_le64(val);
    } else {
        val = cpu_to_be64(val);
    }

    return val;
}

typedef struct DumpState {
    ArchDumpInfo dump_info;
    MemoryMappingList list;
    uint16_t phdr_num;
    uint32_t sh_info;
    bool have_section;
    bool resume;
    size_t note_size;
    hwaddr memory_offset;
    int fd;

    RAMBlock *block;
    ram_addr_t start;
    bool has_filter;
    int64_t begin;
    int64_t length;
    Error **errp;
} DumpState;

static int dump_cleanup(DumpState *s)
{
    int ret = 0;

    memory_mapping_list_free(&s->list);
    if (s->fd != -1) {
        close(s->fd);
    }
    if (s->resume) {
        vm_start();
    }

    return ret;
}

static void dump_error(DumpState *s, const char *reason)
{
    dump_cleanup(s);
}

static int fd_write_vmcore(void *buf, size_t size, void *opaque)
{
    DumpState *s = opaque;
    size_t written_size;

    written_size = qemu_write_full(s->fd, buf, size);
    if (written_size != size) {
        return -1;
    }

    return 0;
}

static int write_elf64_header(DumpState *s)
{
    Elf64_Ehdr elf_header;
    int ret;
    int endian = s->dump_info.d_endian;

    memset(&elf_header, 0, sizeof(Elf64_Ehdr));
    memcpy(&elf_header, ELFMAG, SELFMAG);
    elf_header.e_ident[EI_CLASS] = ELFCLASS64;
    elf_header.e_ident[EI_DATA] = s->dump_info.d_endian;
    elf_header.e_ident[EI_VERSION] = EV_CURRENT;
    elf_header.e_type = cpu_convert_to_target16(ET_CORE, endian);
    elf_header.e_machine = cpu_convert_to_target16(s->dump_info.d_machine,
                                                   endian);
    elf_header.e_version = cpu_convert_to_target32(EV_CURRENT, endian);
    elf_header.e_ehsize = cpu_convert_to_target16(sizeof(elf_header), endian);
    elf_header.e_phoff = cpu_convert_to_target64(sizeof(Elf64_Ehdr), endian);
    elf_header.e_phentsize = cpu_convert_to_target16(sizeof(Elf64_Phdr),
                                                     endian);
    elf_header.e_phnum = cpu_convert_to_target16(s->phdr_num, endian);
    if (s->have_section) {
        uint64_t shoff = sizeof(Elf64_Ehdr) + sizeof(Elf64_Phdr) * s->sh_info;

        elf_header.e_shoff = cpu_convert_to_target64(shoff, endian);
        elf_header.e_shentsize = cpu_convert_to_target16(sizeof(Elf64_Shdr),
                                                         endian);
        elf_header.e_shnum = cpu_convert_to_target16(1, endian);
    }

    ret = fd_write_vmcore(&elf_header, sizeof(elf_header), s);
    if (ret < 0) {
        dump_error(s, "dump: failed to write elf header.\n");
        return -1;
    }

    return 0;
}

static int write_elf32_header(DumpState *s)
{
    Elf32_Ehdr elf_header;
    int ret;
    int endian = s->dump_info.d_endian;

    memset(&elf_header, 0, sizeof(Elf32_Ehdr));
    memcpy(&elf_header, ELFMAG, SELFMAG);
    elf_header.e_ident[EI_CLASS] = ELFCLASS32;
    elf_header.e_ident[EI_DATA] = endian;
    elf_header.e_ident[EI_VERSION] = EV_CURRENT;
    elf_header.e_type = cpu_convert_to_target16(ET_CORE, endian);
    elf_header.e_machine = cpu_convert_to_target16(s->dump_info.d_machine,
                                                   endian);
    elf_header.e_version = cpu_convert_to_target32(EV_CURRENT, endian);
    elf_header.e_ehsize = cpu_convert_to_target16(sizeof(elf_header), endian);
    elf_header.e_phoff = cpu_convert_to_target32(sizeof(Elf32_Ehdr), endian);
    elf_header.e_phentsize = cpu_convert_to_target16(sizeof(Elf32_Phdr),
                                                     endian);
    elf_header.e_phnum = cpu_convert_to_target16(s->phdr_num, endian);
    if (s->have_section) {
        uint32_t shoff = sizeof(Elf32_Ehdr) + sizeof(Elf32_Phdr) * s->sh_info;

        elf_header.e_shoff = cpu_convert_to_target32(shoff, endian);
        elf_header.e_shentsize = cpu_convert_to_target16(sizeof(Elf32_Shdr),
                                                         endian);
        elf_header.e_shnum = cpu_convert_to_target16(1, endian);
    }

    ret = fd_write_vmcore(&elf_header, sizeof(elf_header), s);
    if (ret < 0) {
        dump_error(s, "dump: failed to write elf header.\n");
        return -1;
    }

    return 0;
}

static int write_elf64_load(DumpState *s, MemoryMapping *memory_mapping,
                            int phdr_index, hwaddr offset)
{
    Elf64_Phdr phdr;
    int ret;
    int endian = s->dump_info.d_endian;

    memset(&phdr, 0, sizeof(Elf64_Phdr));
    phdr.p_type = cpu_convert_to_target32(PT_LOAD, endian);
    phdr.p_offset = cpu_convert_to_target64(offset, endian);
    phdr.p_paddr = cpu_convert_to_target64(memory_mapping->phys_addr, endian);
    if (offset == -1) {
        /* When the memory is not stored into vmcore, offset will be -1 */
        phdr.p_filesz = 0;
    } else {
        phdr.p_filesz = cpu_convert_to_target64(memory_mapping->length, endian);
    }
    phdr.p_memsz = cpu_convert_to_target64(memory_mapping->length, endian);
    phdr.p_vaddr = cpu_convert_to_target64(memory_mapping->virt_addr, endian);

    ret = fd_write_vmcore(&phdr, sizeof(Elf64_Phdr), s);
    if (ret < 0) {
        dump_error(s, "dump: failed to write program header table.\n");
        return -1;
    }

    return 0;
}

static int write_elf32_load(DumpState *s, MemoryMapping *memory_mapping,
                            int phdr_index, hwaddr offset)
{
    Elf32_Phdr phdr;
    int ret;
    int endian = s->dump_info.d_endian;

    memset(&phdr, 0, sizeof(Elf32_Phdr));
    phdr.p_type = cpu_convert_to_target32(PT_LOAD, endian);
    phdr.p_offset = cpu_convert_to_target32(offset, endian);
    phdr.p_paddr = cpu_convert_to_target32(memory_mapping->phys_addr, endian);
    if (offset == -1) {
        /* When the memory is not stored into vmcore, offset will be -1 */
        phdr.p_filesz = 0;
    } else {
        phdr.p_filesz = cpu_convert_to_target32(memory_mapping->length, endian);
    }
    phdr.p_memsz = cpu_convert_to_target32(memory_mapping->length, endian);
    phdr.p_vaddr = cpu_convert_to_target32(memory_mapping->virt_addr, endian);

    ret = fd_write_vmcore(&phdr, sizeof(Elf32_Phdr), s);
    if (ret < 0) {
        dump_error(s, "dump: failed to write program header table.\n");
        return -1;
    }

    return 0;
}

static int write_elf64_note(DumpState *s)
{
    Elf64_Phdr phdr;
    int endian = s->dump_info.d_endian;
    hwaddr begin = s->memory_offset - s->note_size;
    int ret;

    memset(&phdr, 0, sizeof(Elf64_Phdr));
    phdr.p_type = cpu_convert_to_target32(PT_NOTE, endian);
    phdr.p_offset = cpu_convert_to_target64(begin, endian);
    phdr.p_paddr = 0;
    phdr.p_filesz = cpu_convert_to_target64(s->note_size, endian);
    phdr.p_memsz = cpu_convert_to_target64(s->note_size, endian);
    phdr.p_vaddr = 0;

    ret = fd_write_vmcore(&phdr, sizeof(Elf64_Phdr), s);
    if (ret < 0) {
        dump_error(s, "dump: failed to write program header table.\n");
        return -1;
    }

    return 0;
}

static inline int cpu_index(CPUState *cpu)
{
    return cpu->cpu_index + 1;
}

static int write_elf64_notes(DumpState *s)
{
    CPUArchState *env;
    CPUState *cpu;
    int ret;
    int id;

    for (env = first_cpu; env != NULL; env = env->next_cpu) {
        cpu = ENV_GET_CPU(env);
        id = cpu_index(cpu);
        ret = cpu_write_elf64_note(fd_write_vmcore, cpu, id, s);
        if (ret < 0) {
            dump_error(s, "dump: failed to write elf notes.\n");
            return -1;
        }
    }

    for (env = first_cpu; env != NULL; env = env->next_cpu) {
        ret = cpu_write_elf64_qemunote(fd_write_vmcore, cpu, s);
        if (ret < 0) {
            dump_error(s, "dump: failed to write CPU status.\n");
            return -1;
        }
    }

    return 0;
}

static int write_elf32_note(DumpState *s)
{
    hwaddr begin = s->memory_offset - s->note_size;
    Elf32_Phdr phdr;
    int endian = s->dump_info.d_endian;
    int ret;

    memset(&phdr, 0, sizeof(Elf32_Phdr));
    phdr.p_type = cpu_convert_to_target32(PT_NOTE, endian);
    phdr.p_offset = cpu_convert_to_target32(begin, endian);
    phdr.p_paddr = 0;
    phdr.p_filesz = cpu_convert_to_target32(s->note_size, endian);
    phdr.p_memsz = cpu_convert_to_target32(s->note_size, endian);
    phdr.p_vaddr = 0;

    ret = fd_write_vmcore(&phdr, sizeof(Elf32_Phdr), s);
    if (ret < 0) {
        dump_error(s, "dump: failed to write program header table.\n");
        return -1;
    }

    return 0;
}

static int write_elf32_notes(DumpState *s)
{
    CPUArchState *env;
    CPUState *cpu;
    int ret;
    int id;

    for (env = first_cpu; env != NULL; env = env->next_cpu) {
        cpu = ENV_GET_CPU(env);
        id = cpu_index(cpu);
        ret = cpu_write_elf32_note(fd_write_vmcore, cpu, id, s);
        if (ret < 0) {
            dump_error(s, "dump: failed to write elf notes.\n");
            return -1;
        }
    }

    for (env = first_cpu; env != NULL; env = env->next_cpu) {
        ret = cpu_write_elf32_qemunote(fd_write_vmcore, cpu, s);
        if (ret < 0) {
            dump_error(s, "dump: failed to write CPU status.\n");
            return -1;
        }
    }

    return 0;
}

static int write_elf_section(DumpState *s, int type)
{
    Elf32_Shdr shdr32;
    Elf64_Shdr shdr64;
    int endian = s->dump_info.d_endian;
    int shdr_size;
    void *shdr;
    int ret;

    if (type == 0) {
        shdr_size = sizeof(Elf32_Shdr);
        memset(&shdr32, 0, shdr_size);
        shdr32.sh_info = cpu_convert_to_target32(s->sh_info, endian);
        shdr = &shdr32;
    } else {
        shdr_size = sizeof(Elf64_Shdr);
        memset(&shdr64, 0, shdr_size);
        shdr64.sh_info = cpu_convert_to_target32(s->sh_info, endian);
        shdr = &shdr64;
    }

    ret = fd_write_vmcore(&shdr, shdr_size, s);
    if (ret < 0) {
        dump_error(s, "dump: failed to write section header table.\n");
        return -1;
    }

    return 0;
}

static int write_data(DumpState *s, void *buf, int length)
{
    int ret;

    ret = fd_write_vmcore(buf, length, s);
    if (ret < 0) {
        dump_error(s, "dump: failed to save memory.\n");
        return -1;
    }

    return 0;
}

/* write the memroy to vmcore. 1 page per I/O. */
static int write_memory(DumpState *s, RAMBlock *block, ram_addr_t start,
                        int64_t size)
{
    int64_t i;
    int ret;

    for (i = 0; i < size / TARGET_PAGE_SIZE; i++) {
        ret = write_data(s, block->host + start + i * TARGET_PAGE_SIZE,
                         TARGET_PAGE_SIZE);
        if (ret < 0) {
            return ret;
        }
    }

    if ((size % TARGET_PAGE_SIZE) != 0) {
        ret = write_data(s, block->host + start + i * TARGET_PAGE_SIZE,
                         size % TARGET_PAGE_SIZE);
        if (ret < 0) {
            return ret;
        }
    }

    return 0;
}

/* get the memory's offset in the vmcore */
static hwaddr get_offset(hwaddr phys_addr,
                                     DumpState *s)
{
    RAMBlock *block;
    hwaddr offset = s->memory_offset;
    int64_t size_in_block, start;

    if (s->has_filter) {
        if (phys_addr < s->begin || phys_addr >= s->begin + s->length) {
            return -1;
        }
    }

    QTAILQ_FOREACH(block, &ram_list.blocks, next) {
        if (s->has_filter) {
            if (block->offset >= s->begin + s->length ||
                block->offset + block->length <= s->begin) {
                /* This block is out of the range */
                continue;
            }

            if (s->begin <= block->offset) {
                start = block->offset;
            } else {
                start = s->begin;
            }

            size_in_block = block->length - (start - block->offset);
            if (s->begin + s->length < block->offset + block->length) {
                size_in_block -= block->offset + block->length -
                                 (s->begin + s->length);
            }
        } else {
            start = block->offset;
            size_in_block = block->length;
        }

        if (phys_addr >= start && phys_addr < start + size_in_block) {
            return phys_addr - start + offset;
        }

        offset += size_in_block;
    }

    return -1;
}

static int write_elf_loads(DumpState *s)
{
    hwaddr offset;
    MemoryMapping *memory_mapping;
    uint32_t phdr_index = 1;
    int ret;
    uint32_t max_index;

    if (s->have_section) {
        max_index = s->sh_info;
    } else {
        max_index = s->phdr_num;
    }

    QTAILQ_FOREACH(memory_mapping, &s->list.head, next) {
        offset = get_offset(memory_mapping->phys_addr, s);
        if (s->dump_info.d_class == ELFCLASS64) {
            ret = write_elf64_load(s, memory_mapping, phdr_index++, offset);
        } else {
            ret = write_elf32_load(s, memory_mapping, phdr_index++, offset);
        }

        if (ret < 0) {
            return -1;
        }

        if (phdr_index >= max_index) {
            break;
        }
    }

    return 0;
}

/* write elf header, PT_NOTE and elf note to vmcore. */
static int dump_begin(DumpState *s)
{
    int ret;

    /*
     * the vmcore's format is:
     *   --------------
     *   |  elf header |
     *   --------------
     *   |  PT_NOTE    |
     *   --------------
     *   |  PT_LOAD    |
     *   --------------
     *   |  ......     |
     *   --------------
     *   |  PT_LOAD    |
     *   --------------
     *   |  sec_hdr    |
     *   --------------
     *   |  elf note   |
     *   --------------
     *   |  memory     |
     *   --------------
     *
     * we only know where the memory is saved after we write elf note into
     * vmcore.
     */

    /* write elf header to vmcore */
    if (s->dump_info.d_class == ELFCLASS64) {
        ret = write_elf64_header(s);
    } else {
        ret = write_elf32_header(s);
    }
    if (ret < 0) {
        return -1;
    }

    if (s->dump_info.d_class == ELFCLASS64) {
        /* write PT_NOTE to vmcore */
        if (write_elf64_note(s) < 0) {
            return -1;
        }

        /* write all PT_LOAD to vmcore */
        if (write_elf_loads(s) < 0) {
            return -1;
        }

        /* write section to vmcore */
        if (s->have_section) {
            if (write_elf_section(s, 1) < 0) {
                return -1;
            }
        }

        /* write notes to vmcore */
        if (write_elf64_notes(s) < 0) {
            return -1;
        }

    } else {
        /* write PT_NOTE to vmcore */
        if (write_elf32_note(s) < 0) {
            return -1;
        }

        /* write all PT_LOAD to vmcore */
        if (write_elf_loads(s) < 0) {
            return -1;
        }

        /* write section to vmcore */
        if (s->have_section) {
            if (write_elf_section(s, 0) < 0) {
                return -1;
            }
        }

        /* write notes to vmcore */
        if (write_elf32_notes(s) < 0) {
            return -1;
        }
    }

    return 0;
}

/* write PT_LOAD to vmcore */
static int dump_completed(DumpState *s)
{
    dump_cleanup(s);
    return 0;
}

static int get_next_block(DumpState *s, RAMBlock *block)
{
    while (1) {
        block = QTAILQ_NEXT(block, next);
        if (!block) {
            /* no more block */
            return 1;
        }

        s->start = 0;
        s->block = block;
        if (s->has_filter) {
            if (block->offset >= s->begin + s->length ||
                block->offset + block->length <= s->begin) {
                /* This block is out of the range */
                continue;
            }

            if (s->begin > block->offset) {
                s->start = s->begin - block->offset;
            }
        }

        return 0;
    }
}

/* write all memory to vmcore */
static int dump_iterate(DumpState *s)
{
    RAMBlock *block;
    int64_t size;
    int ret;

    while (1) {
        block = s->block;

        size = block->length;
        if (s->has_filter) {
            size -= s->start;
            if (s->begin + s->length < block->offset + block->length) {
                size -= block->offset + block->length - (s->begin + s->length);
            }
        }
        ret = write_memory(s, block, s->start, size);
        if (ret == -1) {
            return ret;
        }

        ret = get_next_block(s, block);
        if (ret == 1) {
            dump_completed(s);
            return 0;
        }
    }
}

static int create_vmcore(DumpState *s)
{
    int ret;

    ret = dump_begin(s);
    if (ret < 0) {
        return -1;
    }

    ret = dump_iterate(s);
    if (ret < 0) {
        return -1;
    }

    return 0;
}

static ram_addr_t get_start_block(DumpState *s)
{
    RAMBlock *block;

    if (!s->has_filter) {
        s->block = QTAILQ_FIRST(&ram_list.blocks);
        return 0;
    }

    QTAILQ_FOREACH(block, &ram_list.blocks, next) {
        if (block->offset >= s->begin + s->length ||
            block->offset + block->length <= s->begin) {
            /* This block is out of the range */
            continue;
        }

        s->block = block;
        if (s->begin > block->offset) {
            s->start = s->begin - block->offset;
        } else {
            s->start = 0;
        }
        return s->start;
    }

    return -1;
}

static int dump_init(DumpState *s, int fd, bool paging, bool has_filter,
                     int64_t begin, int64_t length, Error **errp)
{
    CPUArchState *env;
    int nr_cpus;
    Error *err = NULL;
    int ret;

    if (runstate_is_running()) {
        vm_stop(RUN_STATE_SAVE_VM);
        s->resume = true;
    } else {
        s->resume = false;
    }

    s->errp = errp;
    s->fd = fd;
    s->has_filter = has_filter;
    s->begin = begin;
    s->length = length;
    s->start = get_start_block(s);
    if (s->start == -1) {
        error_set(errp, QERR_INVALID_PARAMETER, "begin");
        goto cleanup;
    }

    /*
     * get dump info: endian, class and architecture.
     * If the target architecture is not supported, cpu_get_dump_info() will
     * return -1.
     *
     * If we use KVM, we should synchronize the registers before we get dump
     * info.
     */
    cpu_synchronize_all_states();
    nr_cpus = 0;
    for (env = first_cpu; env != NULL; env = env->next_cpu) {
        nr_cpus++;
    }

    ret = cpu_get_dump_info(&s->dump_info);
    if (ret < 0) {
        error_set(errp, QERR_UNSUPPORTED);
        goto cleanup;
    }

    s->note_size = cpu_get_note_size(s->dump_info.d_class,
                                     s->dump_info.d_machine, nr_cpus);
    if (ret < 0) {
        error_set(errp, QERR_UNSUPPORTED);
        goto cleanup;
    }

    /* get memory mapping */
    memory_mapping_list_init(&s->list);
    if (paging) {
        qemu_get_guest_memory_mapping(&s->list, &err);
        if (err != NULL) {
            error_propagate(errp, err);
            goto cleanup;
        }
    } else {
        qemu_get_guest_simple_memory_mapping(&s->list);
    }

    if (s->has_filter) {
        memory_mapping_filter(&s->list, s->begin, s->length);
    }

    /*
     * calculate phdr_num
     *
     * the type of ehdr->e_phnum is uint16_t, so we should avoid overflow
     */
    s->phdr_num = 1; /* PT_NOTE */
    if (s->list.num < UINT16_MAX - 2) {
        s->phdr_num += s->list.num;
        s->have_section = false;
    } else {
        s->have_section = true;
        s->phdr_num = PN_XNUM;
        s->sh_info = 1; /* PT_NOTE */

        /* the type of shdr->sh_info is uint32_t, so we should avoid overflow */
        if (s->list.num <= UINT32_MAX - 1) {
            s->sh_info += s->list.num;
        } else {
            s->sh_info = UINT32_MAX;
        }
    }

    if (s->dump_info.d_class == ELFCLASS64) {
        if (s->have_section) {
            s->memory_offset = sizeof(Elf64_Ehdr) +
                               sizeof(Elf64_Phdr) * s->sh_info +
                               sizeof(Elf64_Shdr) + s->note_size;
        } else {
            s->memory_offset = sizeof(Elf64_Ehdr) +
                               sizeof(Elf64_Phdr) * s->phdr_num + s->note_size;
        }
    } else {
        if (s->have_section) {
            s->memory_offset = sizeof(Elf32_Ehdr) +
                               sizeof(Elf32_Phdr) * s->sh_info +
                               sizeof(Elf32_Shdr) + s->note_size;
        } else {
            s->memory_offset = sizeof(Elf32_Ehdr) +
                               sizeof(Elf32_Phdr) * s->phdr_num + s->note_size;
        }
    }

    return 0;

cleanup:
    if (s->resume) {
        vm_start();
    }

    return -1;
}

void qmp_dump_guest_memory(bool paging, const char *file, bool has_begin,
                           int64_t begin, bool has_length, int64_t length,
                           Error **errp)
{
    const char *p;
    int fd = -1;
    DumpState *s;
    int ret;

    if (has_begin && !has_length) {
        error_set(errp, QERR_MISSING_PARAMETER, "length");
        return;
    }
    if (!has_begin && has_length) {
        error_set(errp, QERR_MISSING_PARAMETER, "begin");
        return;
    }

#if !defined(WIN32)
    if (strstart(file, "fd:", &p)) {
        fd = monitor_get_fd(cur_mon, p, errp);
        if (fd == -1) {
            return;
        }
    }
#endif

    if  (strstart(file, "file:", &p)) {
        fd = qemu_open(p, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, S_IRUSR);
        if (fd < 0) {
            error_setg_file_open(errp, errno, p);
            return;
        }
    }

    if (fd == -1) {
        error_set(errp, QERR_INVALID_PARAMETER, "protocol");
        return;
    }

    s = g_malloc(sizeof(DumpState));

    ret = dump_init(s, fd, paging, has_begin, begin, length, errp);
    if (ret < 0) {
        g_free(s);
        return;
    }

    if (create_vmcore(s) < 0 && !error_is_set(s->errp)) {
        error_set(errp, QERR_IO_ERROR);
    }

    g_free(s);
}