Re: [Qemu-devel] [RFC][PATCH 09/16 v6] introduce a new monitor command 'dump' to dump guest's memory

[Wen Congyang <wency@cn.fujitsu.com>]

At 02/15/2012 01:59 AM, Jan Kiszka Wrote:
> On 2012-02-09 04:28, Wen Congyang wrote:
>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>> ---
>>  Makefile.target  |    8 +-
>>  dump.c           |  590 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  dump.h           |    3 +
>>  hmp-commands.hx  |   16 ++
>>  hmp.c            |    9 +
>>  hmp.h            |    1 +
>>  monitor.c        |    3 +
>>  qapi-schema.json |   13 ++
>>  qmp-commands.hx  |   26 +++
>>  9 files changed, 665 insertions(+), 4 deletions(-)
>>  create mode 100644 dump.c
>>
>> diff --git a/Makefile.target b/Makefile.target
>> index d6e5684..f39ce2f 100644
>> --- a/Makefile.target
>> +++ b/Makefile.target
>> @@ -112,7 +112,7 @@ $(call set-vpath, $(SRC_PATH)/linux-user:$(SRC_PATH)/linux-user/$(TARGET_ABI_DIR
>>  QEMU_CFLAGS+=-I$(SRC_PATH)/linux-user/$(TARGET_ABI_DIR) -I$(SRC_PATH)/linux-user
>>  obj-y = main.o syscall.o strace.o mmap.o signal.o thunk.o \
>>        elfload.o linuxload.o uaccess.o gdbstub.o cpu-uname.o \
>> -      user-exec.o $(oslib-obj-y)
>> +      user-exec.o $(oslib-obj-y) dump.o
>>
>>  obj-$(TARGET_HAS_BFLT) += flatload.o
>>
>> @@ -150,7 +150,7 @@ LDFLAGS+=-Wl,-segaddr,__STD_PROG_ZONE,0x1000 -image_base 0x0e000000
>>  LIBS+=-lmx
>>
>>  obj-y = main.o commpage.o machload.o mmap.o signal.o syscall.o thunk.o \
>> -        gdbstub.o user-exec.o
>> +        gdbstub.o user-exec.o dump.o
>>
>>  obj-i386-y += ioport-user.o
>>
>> @@ -172,7 +172,7 @@ $(call set-vpath, $(SRC_PATH)/bsd-user)
>>  QEMU_CFLAGS+=-I$(SRC_PATH)/bsd-user -I$(SRC_PATH)/bsd-user/$(TARGET_ARCH)
>>
>>  obj-y = main.o bsdload.o elfload.o mmap.o signal.o strace.o syscall.o \
>> -        gdbstub.o uaccess.o user-exec.o
>> +        gdbstub.o uaccess.o user-exec.o dump.o
>>
>>  obj-i386-y += ioport-user.o
>>
>> @@ -188,7 +188,7 @@ endif #CONFIG_BSD_USER
>>  # System emulator target
>>  ifdef CONFIG_SOFTMMU
>>
>> -obj-y = arch_init.o cpus.o monitor.o machine.o gdbstub.o balloon.o ioport.o
>> +obj-y = arch_init.o cpus.o monitor.o machine.o gdbstub.o balloon.o ioport.o dump.o
>>  # virtio has to be here due to weird dependency between PCI and virtio-net.
>>  # need to fix this properly
>>  obj-$(CONFIG_NO_PCI) += pci-stub.o
>> diff --git a/dump.c b/dump.c
>> new file mode 100644
>> index 0000000..a0e8b86
>> --- /dev/null
>> +++ b/dump.c
>> @@ -0,0 +1,590 @@
>> +/*
>> + * QEMU dump
>> + *
>> + * Copyright Fujitsu, Corp. 2011
>> + *
>> + * Authors:
>> + *     Wen Congyang <wency@cn.fujitsu.com>
>> + *
>> + * This work is licensed under the terms of the GNU GPL, version 2.  See
>> + * the COPYING file in the top-level directory.
>> + *
>> + */
>> +
>> +#include "qemu-common.h"
>> +#include <unistd.h>
>> +#include <elf.h>
>> +#include <sys/procfs.h>
>> +#include <glib.h>
>> +#include "cpu.h"
>> +#include "cpu-all.h"
>> +#include "targphys.h"
>> +#include "monitor.h"
>> +#include "kvm.h"
>> +#include "dump.h"
>> +#include "sysemu.h"
>> +#include "bswap.h"
>> +#include "memory_mapping.h"
>> +#include "error.h"
>> +#include "qmp-commands.h"
>> +
>> +#define CPU_CONVERT_TO_TARGET16(val) \
>> +({ \
>> +    uint16_t _val = (val); \
>> +    if (endian == ELFDATA2LSB) { \
>> +        _val = cpu_to_le16(_val); \
>> +    } else {\
>> +        _val = cpu_to_be16(_val); \
>> +    } \
>> +    _val; \
>> +})
>> +
>> +#define CPU_CONVERT_TO_TARGET32(val) \
>> +({ \
>> +    uint32_t _val = (val); \
>> +    if (endian == ELFDATA2LSB) { \
>> +        _val = cpu_to_le32(_val); \
>> +    } else {\
>> +        _val = cpu_to_be32(_val); \
>> +    } \
>> +    _val; \
>> +})
>> +
>> +#define CPU_CONVERT_TO_TARGET64(val) \
>> +({ \
>> +    uint64_t _val = (val); \
>> +    if (endian == ELFDATA2LSB) { \
>> +        _val = cpu_to_le64(_val); \
>> +    } else {\
>> +        _val = cpu_to_be64(_val); \
>> +    } \
>> +    _val; \
>> +})
> 
> static inline functions, please.

OK

> 
>> +
>> +enum {
>> +    DUMP_STATE_ERROR,
>> +    DUMP_STATE_SETUP,
>> +    DUMP_STATE_CANCELLED,
>> +    DUMP_STATE_ACTIVE,
>> +    DUMP_STATE_COMPLETED,
>> +};
>> +
>> +typedef struct DumpState {
>> +    ArchDumpInfo dump_info;
>> +    MemoryMappingList list;
>> +    int phdr_num;
>> +    int state;
>> +    char *error;
>> +    int fd;
>> +    target_phys_addr_t memory_offset;
>> +} DumpState;
>> +
>> +static DumpState *dump_get_current(void)
>> +{
>> +    static DumpState current_dump = {
>> +        .state = DUMP_STATE_SETUP,
>> +    };
>> +
>> +    return &current_dump;
>> +}
>> +
>> +static int dump_cleanup(DumpState *s)
>> +{
>> +    int ret = 0;
>> +
>> +    free_memory_mapping_list(&s->list);
>> +    if (s->fd != -1) {
>> +        close(s->fd);
>> +        s->fd = -1;
>> +    }
>> +
>> +    return ret;
>> +}
>> +
>> +static void dump_error(DumpState *s, const char *reason)
>> +{
>> +    s->state = DUMP_STATE_ERROR;
>> +    s->error = g_strdup(reason);
>> +    dump_cleanup(s);
>> +}
>> +
>> +static inline int cpuid(CPUState *env)
>> +{
>> +#if defined(CONFIG_USER_ONLY) && defined(CONFIG_USE_NPTL)
>> +    return env->host_tid;
> 
> Curious: Does this command already work with user mode guest?

I think the answer is not. I will change it.

> 
>> +#else
>> +    return env->cpu_index + 1;
>> +#endif
>> +}
> 
> There is gdb_id in gdbstub. It should be made generally avialable and
> reused here.

OK

> 
>> +
>> +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, 4);
>> +    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);
>> +    elf_header.e_machine = CPU_CONVERT_TO_TARGET16(s->dump_info.d_machine);
>> +    elf_header.e_version = CPU_CONVERT_TO_TARGET32(EV_CURRENT);
>> +    elf_header.e_ehsize = CPU_CONVERT_TO_TARGET16(sizeof(elf_header));
>> +    elf_header.e_phoff = CPU_CONVERT_TO_TARGET64(sizeof(Elf64_Ehdr));
>> +    elf_header.e_phentsize = CPU_CONVERT_TO_TARGET16(sizeof(Elf64_Phdr));
>> +    elf_header.e_phnum = CPU_CONVERT_TO_TARGET16(s->phdr_num);
>> +
>> +    lseek(s->fd, 0, SEEK_SET);
>> +    ret = write(s->fd, &elf_header, sizeof(elf_header));
>> +    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, 4);
>> +    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);
>> +    elf_header.e_machine = CPU_CONVERT_TO_TARGET16(s->dump_info.d_machine);
>> +    elf_header.e_version = CPU_CONVERT_TO_TARGET32(EV_CURRENT);
>> +    elf_header.e_ehsize = CPU_CONVERT_TO_TARGET16(sizeof(elf_header));
>> +    elf_header.e_phoff = CPU_CONVERT_TO_TARGET32(sizeof(Elf32_Ehdr));
>> +    elf_header.e_phentsize = CPU_CONVERT_TO_TARGET16(sizeof(Elf32_Phdr));
>> +    elf_header.e_phnum = CPU_CONVERT_TO_TARGET16(s->phdr_num);
>> +
>> +    lseek(s->fd, 0, SEEK_SET);
>> +    ret = write(s->fd, &elf_header, sizeof(elf_header));
>> +    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, target_phys_addr_t offset)
>> +{
>> +    Elf64_Phdr phdr;
>> +    off_t phdr_offset;
>> +    int ret;
>> +    int endian = s->dump_info.d_endian;
>> +
>> +    memset(&phdr, 0, sizeof(Elf64_Phdr));
>> +    phdr.p_type = CPU_CONVERT_TO_TARGET32(PT_LOAD);
>> +    phdr.p_offset = CPU_CONVERT_TO_TARGET64(offset);
>> +    phdr.p_paddr = CPU_CONVERT_TO_TARGET64(memory_mapping->phys_addr);
>> +    if (offset == -1) {
>> +        phdr.p_filesz = 0;
>> +    } else {
>> +        phdr.p_filesz = CPU_CONVERT_TO_TARGET64(memory_mapping->length);
>> +    }
>> +    phdr.p_memsz = CPU_CONVERT_TO_TARGET64(memory_mapping->length);
>> +    phdr.p_vaddr = CPU_CONVERT_TO_TARGET64(memory_mapping->virt_addr);
>> +
>> +    phdr_offset = sizeof(Elf64_Ehdr) + sizeof(Elf64_Phdr)*phdr_index;
>> +    lseek(s->fd, phdr_offset, SEEK_SET);
>> +    ret = write(s->fd, &phdr, sizeof(Elf64_Phdr));
>> +    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, target_phys_addr_t offset)
>> +{
>> +    Elf32_Phdr phdr;
>> +    off_t phdr_offset;
>> +    int ret;
>> +    int endian = s->dump_info.d_endian;
>> +
>> +    memset(&phdr, 0, sizeof(Elf32_Phdr));
>> +    phdr.p_type = CPU_CONVERT_TO_TARGET32(PT_LOAD);
>> +    phdr.p_offset = CPU_CONVERT_TO_TARGET32(offset);
>> +    phdr.p_paddr = CPU_CONVERT_TO_TARGET32(memory_mapping->phys_addr);
>> +    if (offset == -1) {
>> +        phdr.p_filesz = 0;
>> +    } else {
>> +        phdr.p_filesz = CPU_CONVERT_TO_TARGET32(memory_mapping->length);
>> +    }
>> +    phdr.p_memsz = CPU_CONVERT_TO_TARGET32(memory_mapping->length);
>> +    phdr.p_vaddr = CPU_CONVERT_TO_TARGET32(memory_mapping->virt_addr);
>> +
>> +    phdr_offset = sizeof(Elf32_Ehdr) + sizeof(Elf32_Phdr)*phdr_index;
>> +    lseek(s->fd, phdr_offset, SEEK_SET);
>> +    ret = write(s->fd, &phdr, sizeof(Elf32_Phdr));
>> +    if (ret < 0) {
>> +        dump_error(s, "dump: failed to write program header table.\n");
>> +        return -1;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int write_elf64_notes(DumpState *s, int phdr_index,
>> +                             target_phys_addr_t *offset)
>> +{
>> +    CPUState *env;
>> +    int ret;
>> +    target_phys_addr_t begin = *offset;
>> +    Elf64_Phdr phdr;
>> +    off_t phdr_offset;
>> +    int id;
>> +    int endian = s->dump_info.d_endian;
>> +
>> +    for (env = first_cpu; env != NULL; env = env->next_cpu) {
>> +        id = cpuid(env);
>> +        ret = cpu_write_elf64_note(s->fd, env, id, offset);
>> +        if (ret < 0) {
>> +            dump_error(s, "dump: failed to write elf notes.\n");
>> +            return -1;
>> +        }
>> +    }
>> +
>> +    memset(&phdr, 0, sizeof(Elf64_Phdr));
>> +    phdr.p_type = CPU_CONVERT_TO_TARGET32(PT_NOTE);
>> +    phdr.p_offset = CPU_CONVERT_TO_TARGET64(begin);
>> +    phdr.p_paddr = 0;
>> +    phdr.p_filesz = CPU_CONVERT_TO_TARGET64(*offset - begin);
>> +    phdr.p_memsz = CPU_CONVERT_TO_TARGET64(*offset - begin);
>> +    phdr.p_vaddr = 0;
>> +
>> +    phdr_offset = sizeof(Elf64_Ehdr);
>> +    lseek(s->fd, phdr_offset, SEEK_SET);
>> +    ret = write(s->fd, &phdr, sizeof(Elf64_Phdr));
>> +    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, int phdr_index,
>> +                             target_phys_addr_t *offset)
>> +{
>> +    CPUState *env;
>> +    int ret;
>> +    target_phys_addr_t begin = *offset;
>> +    Elf32_Phdr phdr;
>> +    off_t phdr_offset;
>> +    int id;
>> +    int endian = s->dump_info.d_endian;
>> +
>> +    for (env = first_cpu; env != NULL; env = env->next_cpu) {
>> +        id = cpuid(env);
>> +        ret = cpu_write_elf32_note(s->fd, env, id, offset);
>> +        if (ret < 0) {
>> +            dump_error(s, "dump: failed to write elf notes.\n");
>> +            return -1;
>> +        }
>> +    }
>> +
>> +    memset(&phdr, 0, sizeof(Elf32_Phdr));
>> +    phdr.p_type = CPU_CONVERT_TO_TARGET32(PT_NOTE);
>> +    phdr.p_offset = CPU_CONVERT_TO_TARGET32(begin);
>> +    phdr.p_paddr = 0;
>> +    phdr.p_filesz = CPU_CONVERT_TO_TARGET32(*offset - begin);
>> +    phdr.p_memsz = CPU_CONVERT_TO_TARGET32(*offset - begin);
>> +    phdr.p_vaddr = 0;
>> +
>> +    phdr_offset = sizeof(Elf32_Ehdr);
>> +    lseek(s->fd, phdr_offset, SEEK_SET);
>> +    ret = write(s->fd, &phdr, sizeof(Elf32_Phdr));
>> +    if (ret < 0) {
>> +        dump_error(s, "dump: failed to write program header table.\n");
>> +        return -1;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int write_data(DumpState *s, void *buf, int length,
>> +                      target_phys_addr_t *offset)
>> +{
>> +    int ret;
>> +
>> +    lseek(s->fd, *offset, SEEK_SET);
>> +    ret = write(s->fd, buf, length);
>> +    if (ret < 0) {
>> +        dump_error(s, "dump: failed to save memory.\n");
>> +        return -1;
>> +    }
>> +
>> +    *offset += length;
>> +    return 0;
>> +}
>> +
>> +/* write the memroy to vmcore. 1 page per I/O. */
>> +static int write_memory(DumpState *s, RAMBlock *block,
>> +                        target_phys_addr_t *offset)
>> +{
>> +    int i, ret;
>> +
>> +    for (i = 0; i < block->length / TARGET_PAGE_SIZE; i++) {
>> +        ret = write_data(s, block->host + i * TARGET_PAGE_SIZE,
>> +                         TARGET_PAGE_SIZE, offset);
>> +        if (ret < 0) {
>> +            return -1;
>> +        }
>> +    }
>> +
>> +    if ((block->length % TARGET_PAGE_SIZE) != 0) {
>> +        ret = write_data(s, block->host + i * TARGET_PAGE_SIZE,
>> +                         block->length % TARGET_PAGE_SIZE, offset);
>> +        if (ret < 0) {
>> +            return -1;
>> +        }
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +/* get the memory's offset in the vmcore */
>> +static target_phys_addr_t get_offset(target_phys_addr_t phys_addr,
>> +                                     target_phys_addr_t memory_offset)
>> +{
>> +    RAMBlock *block;
>> +    target_phys_addr_t offset = memory_offset;
>> +
>> +    QLIST_FOREACH(block, &ram_list.blocks, next) {
>> +        if (phys_addr >= block->offset &&
>> +            phys_addr < block->offset + block->length) {
>> +            return phys_addr - block->offset + offset;
>> +        }
>> +        offset += block->length;
>> +    }
>> +
>> +    return -1;
>> +}
>> +
>> +static DumpState *dump_init(int fd, Error **errp)
>> +{
>> +    CPUState *env;
>> +    DumpState *s = dump_get_current();
>> +    int ret;
>> +
>> +    vm_stop(RUN_STATE_PAUSED);
> 
> I would save the current vm state first and restore it when finished.

OK, I will do it.

> 
>> +    s->state = DUMP_STATE_SETUP;
>> +    if (s->error) {
>> +        g_free(s->error);
>> +        s->error = NULL;
>> +    }
>> +    s->fd = fd;
>> +
>> +    /*
>> +     * 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 register before we get dump
>> +     * info.
>> +     */
>> +    for (env = first_cpu; env != NULL; env = env->next_cpu) {
>> +        cpu_synchronize_state(env);
>> +    }
>> +    ret = cpu_get_dump_info(&s->dump_info);
>> +    if (ret < 0) {
>> +        error_set(errp, QERR_UNSUPPORTED);
>> +        return NULL;
>> +    }
>> +
>> +    /* get memory mapping */
>> +    s->list.num = 0;
>> +    QTAILQ_INIT(&s->list.head);
>> +    get_memory_mapping(&s->list);
>> +
>> +    /* crash needs extra memory mapping to determine phys_base. */
>> +    ret = cpu_add_extra_memory_mapping(&s->list);
>> +    if (ret < 0) {
>> +        error_set(errp, QERR_UNDEFINED_ERROR);
>> +        return NULL;
>> +    }
>> +
>> +    /*
>> +     * calculate phdr_num
>> +     *
>> +     * the type of phdr->num is uint16_t, so we should avoid overflow
>> +     */
>> +    s->phdr_num = 1; /* PT_NOTE */
>> +    if (s->list.num > (1 << 16) - 2) {
>> +        s->phdr_num = (1 << 16) - 1;
>> +    } else {
>> +        s->phdr_num += s->list.num;
>> +    }
>> +
>> +    return s;
>> +}
>> +
>> +/* write elf header, PT_NOTE and elf note to vmcore. */
>> +static int dump_begin(DumpState *s)
>> +{
>> +    target_phys_addr_t offset;
>> +    int ret;
>> +
>> +    s->state = DUMP_STATE_ACTIVE;
>> +
>> +    /*
>> +     * the vmcore's format is:
>> +     *   --------------
>> +     *   |  elf header |
>> +     *   --------------
>> +     *   |  PT_NOTE    |
>> +     *   --------------
>> +     *   |  PT_LOAD    |
>> +     *   --------------
>> +     *   |  ......     |
>> +     *   --------------
>> +     *   |  PT_LOAD    |
>> +     *   --------------
>> +     *   |  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;
>> +    }
>> +
>> +    /* write elf notes to vmcore */
>> +    if (s->dump_info.d_class == ELFCLASS64) {
>> +        offset = sizeof(Elf64_Ehdr) + sizeof(Elf64_Phdr)*s->phdr_num;
>> +        ret = write_elf64_notes(s, 0, &offset);
>> +    } else {
>> +        offset = sizeof(Elf32_Ehdr) + sizeof(Elf32_Phdr)*s->phdr_num;
>> +        ret = write_elf32_notes(s, 0, &offset);
>> +    }
>> +
>> +    if (ret < 0) {
>> +        return -1;
>> +    }
>> +
>> +    s->memory_offset = offset;
>> +    return 0;
>> +}
>> +
>> +/* write PT_LOAD to vmcore */
>> +static int dump_completed(DumpState *s)
>> +{
>> +    target_phys_addr_t offset;
>> +    MemoryMapping *memory_mapping;
>> +    int phdr_index = 1, ret;
>> +
>> +    QTAILQ_FOREACH(memory_mapping, &s->list.head, next) {
>> +        offset = get_offset(memory_mapping->phys_addr, s->memory_offset);
>> +        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;
>> +        }
>> +    }
>> +
>> +    s->state = DUMP_STATE_COMPLETED;
>> +    dump_cleanup(s);
>> +    return 0;
>> +}
>> +
>> +/* write all memory to vmcore */
>> +static int dump_iterate(DumpState *s)
>> +{
>> +    RAMBlock *block;
>> +    target_phys_addr_t offset = s->memory_offset;
>> +    int ret;
>> +
>> +    /* write all memory to vmcore */
>> +    QLIST_FOREACH(block, &ram_list.blocks, next) {
>> +        ret = write_memory(s, block, &offset);
>> +        if (ret < 0) {
>> +            return -1;
>> +        }
>> +    }
>> +
>> +    return dump_completed(s);
>> +}
>> +
>> +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;
>> +}
>> +
>> +void qmp_dump(const char *file, Error **errp)
>> +{
>> +    const char *p;
>> +    int fd = -1;
>> +    DumpState *s;
>> +
>> +#if !defined(WIN32)
>> +    if (strstart(file, "fd:", &p)) {
>> +        fd = qemu_get_fd(p);
>> +        if (fd == -1) {
>> +            error_set(errp, QERR_FD_NOT_FOUND, p);
>> +            return;
>> +        }
>> +    }
>> +#endif
>> +
>> +    if  (strstart(file, "file:", &p)) {
>> +        fd = open(p, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, S_IRUSR);
>> +        if (fd < 0) {
>> +            error_set(errp, QERR_OPEN_FILE_FAILED, p);
>> +            return;
>> +        }
>> +    }
>> +
>> +    if (fd == -1) {
>> +        error_set(errp, QERR_INVALID_PARAMETER, "file");
>> +        return;
>> +    }
>> +
>> +    s = dump_init(fd, errp);
>> +    if (!s) {
>> +        return;
>> +    }
>> +
>> +    if (create_vmcore(s) < 0) {
>> +        error_set(errp, QERR_IO_ERROR);
>> +    }
>> +
>> +    return;
>> +}
>> diff --git a/dump.h b/dump.h
>> index a36468b..b413d18 100644
>> --- a/dump.h
>> +++ b/dump.h
>> @@ -1,6 +1,9 @@
>>  #ifndef DUMP_H
>>  #define DUMP_H
>>
>> +#include "qdict.h"
>> +#include "error.h"
>> +
> 
> This looks stray. Nothing is added to this header which require those
> includes.

Yes, I forgot to remove it when updating the patch. I will remove them.

> 
>>  typedef struct ArchDumpInfo {
>>      int d_machine;  /* Architecture */
>>      int d_endian;   /* ELFDATA2LSB or ELFDATA2MSB */
>> diff --git a/hmp-commands.hx b/hmp-commands.hx
>> index 573b823..6cfb678 100644
>> --- a/hmp-commands.hx
>> +++ b/hmp-commands.hx
>> @@ -867,6 +867,22 @@ new parameters (if specified) once the vm migration finished successfully.
>>  ETEXI
>>
>>      {
>> +        .name       = "dump",
>> +        .args_type  = "file:s",
>> +        .params     = "file",
>> +        .help       = "dump to file",
>> +        .user_print = monitor_user_noop,
>> +        .mhandler.cmd = hmp_dump,
>> +    },
>> +
>> +
>> +STEXI
>> +@item dump @var{file}
>> +@findex dump
>> +Dump to @var{file}.
> 
> That's way too brief! :) It should state the format, mention potential
> architecture limitations, and explain that the output can be processed
> with crash or gdb.

OK.

> 
>> +ETEXI
>> +
>> +    {
>>          .name       = "snapshot_blkdev",
>>          .args_type  = "device:B,snapshot-file:s?,format:s?",
>>          .params     = "device [new-image-file] [format]",
>> diff --git a/hmp.c b/hmp.c
>> index 8ff8c94..1a69857 100644
>> --- a/hmp.c
>> +++ b/hmp.c
>> @@ -851,3 +851,12 @@ void hmp_block_job_cancel(Monitor *mon, const QDict *qdict)
>>
>>      hmp_handle_error(mon, &error);
>>  }
>> +
>> +void hmp_dump(Monitor *mon, const QDict *qdict)
>> +{
>> +    Error *errp = NULL;
>> +    const char *file = qdict_get_str(qdict, "file");
>> +
>> +    qmp_dump(file, &errp);
>> +    hmp_handle_error(mon, &errp);
>> +}
>> diff --git a/hmp.h b/hmp.h
>> index 18eecbd..66984c5 100644
>> --- a/hmp.h
>> +++ b/hmp.h
>> @@ -58,5 +58,6 @@ void hmp_block_set_io_throttle(Monitor *mon, const QDict *qdict);
>>  void hmp_block_stream(Monitor *mon, const QDict *qdict);
>>  void hmp_block_job_set_speed(Monitor *mon, const QDict *qdict);
>>  void hmp_block_job_cancel(Monitor *mon, const QDict *qdict);
>> +void hmp_dump(Monitor *mon, const QDict *qdict);
>>
>>  #endif
>> diff --git a/monitor.c b/monitor.c
>> index 7e72739..18e1ac7 100644
>> --- a/monitor.c
>> +++ b/monitor.c
>> @@ -73,6 +73,9 @@
>>  #endif
>>  #include "hw/lm32_pic.h"
>>
>> +/* for dump */
>> +#include "dump.h"
>> +
>>  //#define DEBUG
>>  //#define DEBUG_COMPLETION
>>
>> diff --git a/qapi-schema.json b/qapi-schema.json
>> index d02ee86..1013ae6 100644
>> --- a/qapi-schema.json
>> +++ b/qapi-schema.json
>> @@ -1582,3 +1582,16 @@
>>  { 'command': 'qom-list-types',
>>    'data': { '*implements': 'str', '*abstract': 'bool' },
>>    'returns': [ 'ObjectTypeInfo' ] }
>> +
>> +##
>> +# @dump
>> +#
>> +# Dump guest's memory to vmcore.
>> +#
>> +# @file: the filename or file descriptor of the vmcore.
>> +#
>> +# Returns: nothing on success
>> +#
>> +# Since: 1.1
>> +##
>> +{ 'command': 'dump', 'data': { 'file': 'str' } }
>> diff --git a/qmp-commands.hx b/qmp-commands.hx
>> index b5e2ab8..52d3d3b 100644
>> --- a/qmp-commands.hx
>> +++ b/qmp-commands.hx
>> @@ -566,6 +566,32 @@ Example:
>>  EQMP
>>
>>      {
>> +        .name       = "dump",
>> +        .args_type  = "file:s",
>> +        .params     = "file",
>> +        .help       = "dump to file",
>> +        .user_print = monitor_user_noop,
>> +        .mhandler.cmd_new = qmp_marshal_input_dump,
>> +    },
>> +
>> +SQMP
>> +dump
>> +
>> +
>> +Dump to file.
>> +
>> +Arguments:
>> +
>> +- "file": Destination file (json-string)
> 
> The code looks like it supports both file names and file descriptors,
> no? Same for HMP.

Yes. I will update the description.

Thanks
Wen Congyang

> 
>> +
>> +Example:
>> +
>> +-> { "execute": "dump", "arguments": { "file": "fd:dump" } }
>> +<- { "return": {} }
>> +
>> +EQMP
>> +
>> +    {
>>          .name       = "netdev_add",
>>          .args_type  = "netdev:O",
>>          .params     = "[user|tap|socket],id=str[,prop=value][,...]",
>> --
>> 1.7.1
>>
> 
> Jan
>