introduce a new monitor command 'dump-guest-memory' to dump guest's memory

The command's usage:
   dump-guest-memory [-p] protocol [begin] [length]
The supported protocol can be file or fd:
1. file: the protocol starts with "file:", and the following string is
   the file's path.
2. fd: the protocol starts with "fd:", and the following string is the
   fd's name.

Note:
  1. If you want to use gdb to process the core, please specify -p option.
     The reason why the -p option is not default is:
       a. guest machine in a catastrophic state can have corrupted memory,
          which we cannot trust.
       b. The guest machine can be in read-mode even if paging is enabled.
          For example: the guest machine uses ACPI to sleep, and ACPI sleep
          state goes in real-mode.
  2. If you don't want to dump all guest's memory, please specify the start
     physical address and the length.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

1 files changed, 883 insertions, 0 deletions

diff --git a/dump.c b/dump.c
new file mode 100644
index 0000000000..0ca14f87ed
--- /dev/null
+++ b/dump.c
@@ -0,0 +1,883 @@
+/*
+ * 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.  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"
+#include "gdbstub.h"
+
+#if defined(CONFIG_HAVE_CORE_DUMP)
+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;
+    target_phys_addr_t 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;
+    int fd = s->fd;
+    size_t writen_size;
+
+    /* The fd may be passed from user, and it can be non-blocked */
+    while (size) {
+        writen_size = qemu_write_full(fd, buf, size);
+        if (writen_size != size && errno != EAGAIN) {
+            return -1;
+        }
+
+        buf += writen_size;
+        size -= writen_size;
+    }
+
+    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, target_phys_addr_t 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, target_phys_addr_t 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;
+    target_phys_addr_t 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 int write_elf64_notes(DumpState *s)
+{
+    CPUArchState *env;
+    int ret;
+    int id;
+
+    for (env = first_cpu; env != NULL; env = env->next_cpu) {
+        id = cpu_index(env);
+        ret = cpu_write_elf64_note(fd_write_vmcore, env, 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, env, 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)
+{
+    target_phys_addr_t 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;
+    int ret;
+    int id;
+
+    for (env = first_cpu; env != NULL; env = env->next_cpu) {
+        id = cpu_index(env);
+        ret = cpu_write_elf32_note(fd_write_vmcore, env, 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, env, 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 target_phys_addr_t get_offset(target_phys_addr_t phys_addr,
+                                     DumpState *s)
+{
+    RAMBlock *block;
+    target_phys_addr_t 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;
+        }
+    }
+
+    QLIST_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)
+{
+    target_phys_addr_t 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 = QLIST_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 = QLIST_FIRST(&ram_list.blocks);
+        return 0;
+    }
+
+    QLIST_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;
+    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 register before we get dump
+     * info.
+     */
+    nr_cpus = 0;
+    for (env = first_cpu; env != NULL; env = env->next_cpu) {
+        cpu_synchronize_state(env);
+        nr_cpus++;
+    }
+
+    ret = cpu_get_dump_info(&s->dump_info);
+    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);
+    } 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;
+        }
+    }
+
+    s->note_size = cpu_get_note_size(s->dump_info.d_class,
+                                     s->dump_info.d_machine, nr_cpus);
+    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);
+        if (fd == -1) {
+            error_set(errp, QERR_FD_NOT_FOUND, p);
+            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_set(errp, QERR_OPEN_FILE_FAILED, 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);
+}
+
+#else
+/* we need this function in hmp.c */
+void qmp_dump_guest_memory(bool paging, const char *file, bool has_begin,
+                           int64_t begin, bool has_length, int64_t length,
+                           Error **errp)
+{
+    error_set(errp, QERR_UNSUPPORTED);
+}
+#endif