Initial import of abandoned HQEMU version 2.5.2HEADmaster

1 files changed, 2195 insertions, 0 deletions

diff --git a/src/migration/savevm.c b/src/migration/savevm.c
new file mode 100644
index 0000000..41be296
--- /dev/null
+++ b/src/migration/savevm.c
@@ -0,0 +1,2195 @@
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ * Copyright (c) 2009-2015 Red Hat Inc
+ *
+ * Authors:
+ *  Juan Quintela <quintela@redhat.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "config-host.h"
+#include "qemu-common.h"
+#include "hw/boards.h"
+#include "hw/hw.h"
+#include "hw/qdev.h"
+#include "net/net.h"
+#include "monitor/monitor.h"
+#include "sysemu/sysemu.h"
+#include "qemu/timer.h"
+#include "audio/audio.h"
+#include "migration/migration.h"
+#include "migration/postcopy-ram.h"
+#include "qapi/qmp/qerror.h"
+#include "qemu/error-report.h"
+#include "qemu/sockets.h"
+#include "qemu/queue.h"
+#include "sysemu/cpus.h"
+#include "exec/memory.h"
+#include "qmp-commands.h"
+#include "trace.h"
+#include "qemu/bitops.h"
+#include "qemu/iov.h"
+#include "block/snapshot.h"
+#include "block/qapi.h"
+
+
+#ifndef ETH_P_RARP
+#define ETH_P_RARP 0x8035
+#endif
+#define ARP_HTYPE_ETH 0x0001
+#define ARP_PTYPE_IP 0x0800
+#define ARP_OP_REQUEST_REV 0x3
+
+const unsigned int postcopy_ram_discard_version = 0;
+
+static bool skip_section_footers;
+
+static struct mig_cmd_args {
+    ssize_t     len; /* -1 = variable */
+    const char *name;
+} mig_cmd_args[] = {
+    [MIG_CMD_INVALID]          = { .len = -1, .name = "INVALID" },
+    [MIG_CMD_OPEN_RETURN_PATH] = { .len =  0, .name = "OPEN_RETURN_PATH" },
+    [MIG_CMD_PING]             = { .len = sizeof(uint32_t), .name = "PING" },
+    [MIG_CMD_POSTCOPY_ADVISE]  = { .len = 16, .name = "POSTCOPY_ADVISE" },
+    [MIG_CMD_POSTCOPY_LISTEN]  = { .len =  0, .name = "POSTCOPY_LISTEN" },
+    [MIG_CMD_POSTCOPY_RUN]     = { .len =  0, .name = "POSTCOPY_RUN" },
+    [MIG_CMD_POSTCOPY_RAM_DISCARD] = {
+                                   .len = -1, .name = "POSTCOPY_RAM_DISCARD" },
+    [MIG_CMD_PACKAGED]         = { .len =  4, .name = "PACKAGED" },
+    [MIG_CMD_MAX]              = { .len = -1, .name = "MAX" },
+};
+
+static int announce_self_create(uint8_t *buf,
+                                uint8_t *mac_addr)
+{
+    /* Ethernet header. */
+    memset(buf, 0xff, 6);         /* destination MAC addr */
+    memcpy(buf + 6, mac_addr, 6); /* source MAC addr */
+    *(uint16_t *)(buf + 12) = htons(ETH_P_RARP); /* ethertype */
+
+    /* RARP header. */
+    *(uint16_t *)(buf + 14) = htons(ARP_HTYPE_ETH); /* hardware addr space */
+    *(uint16_t *)(buf + 16) = htons(ARP_PTYPE_IP); /* protocol addr space */
+    *(buf + 18) = 6; /* hardware addr length (ethernet) */
+    *(buf + 19) = 4; /* protocol addr length (IPv4) */
+    *(uint16_t *)(buf + 20) = htons(ARP_OP_REQUEST_REV); /* opcode */
+    memcpy(buf + 22, mac_addr, 6); /* source hw addr */
+    memset(buf + 28, 0x00, 4);     /* source protocol addr */
+    memcpy(buf + 32, mac_addr, 6); /* target hw addr */
+    memset(buf + 38, 0x00, 4);     /* target protocol addr */
+
+    /* Padding to get up to 60 bytes (ethernet min packet size, minus FCS). */
+    memset(buf + 42, 0x00, 18);
+
+    return 60; /* len (FCS will be added by hardware) */
+}
+
+static void qemu_announce_self_iter(NICState *nic, void *opaque)
+{
+    uint8_t buf[60];
+    int len;
+
+    trace_qemu_announce_self_iter(qemu_ether_ntoa(&nic->conf->macaddr));
+    len = announce_self_create(buf, nic->conf->macaddr.a);
+
+    qemu_send_packet_raw(qemu_get_queue(nic), buf, len);
+}
+
+
+static void qemu_announce_self_once(void *opaque)
+{
+    static int count = SELF_ANNOUNCE_ROUNDS;
+    QEMUTimer *timer = *(QEMUTimer **)opaque;
+
+    qemu_foreach_nic(qemu_announce_self_iter, NULL);
+
+    if (--count) {
+        /* delay 50ms, 150ms, 250ms, ... */
+        timer_mod(timer, qemu_clock_get_ms(QEMU_CLOCK_REALTIME) +
+                  self_announce_delay(count));
+    } else {
+            timer_del(timer);
+            timer_free(timer);
+    }
+}
+
+void qemu_announce_self(void)
+{
+    static QEMUTimer *timer;
+    timer = timer_new_ms(QEMU_CLOCK_REALTIME, qemu_announce_self_once, &timer);
+    qemu_announce_self_once(&timer);
+}
+
+/***********************************************************/
+/* savevm/loadvm support */
+
+static ssize_t block_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
+                                   int64_t pos)
+{
+    int ret;
+    QEMUIOVector qiov;
+
+    qemu_iovec_init_external(&qiov, iov, iovcnt);
+    ret = bdrv_writev_vmstate(opaque, &qiov, pos);
+    if (ret < 0) {
+        return ret;
+    }
+
+    return qiov.size;
+}
+
+static ssize_t block_put_buffer(void *opaque, const uint8_t *buf,
+                                int64_t pos, size_t size)
+{
+    bdrv_save_vmstate(opaque, buf, pos, size);
+    return size;
+}
+
+static ssize_t block_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
+                                size_t size)
+{
+    return bdrv_load_vmstate(opaque, buf, pos, size);
+}
+
+static int bdrv_fclose(void *opaque)
+{
+    return bdrv_flush(opaque);
+}
+
+static const QEMUFileOps bdrv_read_ops = {
+    .get_buffer = block_get_buffer,
+    .close =      bdrv_fclose
+};
+
+static const QEMUFileOps bdrv_write_ops = {
+    .put_buffer     = block_put_buffer,
+    .writev_buffer  = block_writev_buffer,
+    .close          = bdrv_fclose
+};
+
+static QEMUFile *qemu_fopen_bdrv(BlockDriverState *bs, int is_writable)
+{
+    if (is_writable) {
+        return qemu_fopen_ops(bs, &bdrv_write_ops);
+    }
+    return qemu_fopen_ops(bs, &bdrv_read_ops);
+}
+
+
+/* QEMUFile timer support.
+ * Not in qemu-file.c to not add qemu-timer.c as dependency to qemu-file.c
+ */
+
+void timer_put(QEMUFile *f, QEMUTimer *ts)
+{
+    uint64_t expire_time;
+
+    expire_time = timer_expire_time_ns(ts);
+    qemu_put_be64(f, expire_time);
+}
+
+void timer_get(QEMUFile *f, QEMUTimer *ts)
+{
+    uint64_t expire_time;
+
+    expire_time = qemu_get_be64(f);
+    if (expire_time != -1) {
+        timer_mod_ns(ts, expire_time);
+    } else {
+        timer_del(ts);
+    }
+}
+
+
+/* VMState timer support.
+ * Not in vmstate.c to not add qemu-timer.c as dependency to vmstate.c
+ */
+
+static int get_timer(QEMUFile *f, void *pv, size_t size)
+{
+    QEMUTimer *v = pv;
+    timer_get(f, v);
+    return 0;
+}
+
+static void put_timer(QEMUFile *f, void *pv, size_t size)
+{
+    QEMUTimer *v = pv;
+    timer_put(f, v);
+}
+
+const VMStateInfo vmstate_info_timer = {
+    .name = "timer",
+    .get  = get_timer,
+    .put  = put_timer,
+};
+
+
+typedef struct CompatEntry {
+    char idstr[256];
+    int instance_id;
+} CompatEntry;
+
+typedef struct SaveStateEntry {
+    QTAILQ_ENTRY(SaveStateEntry) entry;
+    char idstr[256];
+    int instance_id;
+    int alias_id;
+    int version_id;
+    int section_id;
+    SaveVMHandlers *ops;
+    const VMStateDescription *vmsd;
+    void *opaque;
+    CompatEntry *compat;
+    int is_ram;
+} SaveStateEntry;
+
+typedef struct SaveState {
+    QTAILQ_HEAD(, SaveStateEntry) handlers;
+    int global_section_id;
+    bool skip_configuration;
+    uint32_t len;
+    const char *name;
+} SaveState;
+
+static SaveState savevm_state = {
+    .handlers = QTAILQ_HEAD_INITIALIZER(savevm_state.handlers),
+    .global_section_id = 0,
+    .skip_configuration = false,
+};
+
+void savevm_skip_configuration(void)
+{
+    savevm_state.skip_configuration = true;
+}
+
+
+static void configuration_pre_save(void *opaque)
+{
+    SaveState *state = opaque;
+    const char *current_name = MACHINE_GET_CLASS(current_machine)->name;
+
+    state->len = strlen(current_name);
+    state->name = current_name;
+}
+
+static int configuration_post_load(void *opaque, int version_id)
+{
+    SaveState *state = opaque;
+    const char *current_name = MACHINE_GET_CLASS(current_machine)->name;
+
+    if (strncmp(state->name, current_name, state->len) != 0) {
+        error_report("Machine type received is '%s' and local is '%s'",
+                     state->name, current_name);
+        return -EINVAL;
+    }
+    return 0;
+}
+
+static const VMStateDescription vmstate_configuration = {
+    .name = "configuration",
+    .version_id = 1,
+    .post_load = configuration_post_load,
+    .pre_save = configuration_pre_save,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(len, SaveState),
+        VMSTATE_VBUFFER_ALLOC_UINT32(name, SaveState, 0, NULL, 0, len),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
+static void dump_vmstate_vmsd(FILE *out_file,
+                              const VMStateDescription *vmsd, int indent,
+                              bool is_subsection);
+
+static void dump_vmstate_vmsf(FILE *out_file, const VMStateField *field,
+                              int indent)
+{
+    fprintf(out_file, "%*s{\n", indent, "");
+    indent += 2;
+    fprintf(out_file, "%*s\"field\": \"%s\",\n", indent, "", field->name);
+    fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "",
+            field->version_id);
+    fprintf(out_file, "%*s\"field_exists\": %s,\n", indent, "",
+            field->field_exists ? "true" : "false");
+    fprintf(out_file, "%*s\"size\": %zu", indent, "", field->size);
+    if (field->vmsd != NULL) {
+        fprintf(out_file, ",\n");
+        dump_vmstate_vmsd(out_file, field->vmsd, indent, false);
+    }
+    fprintf(out_file, "\n%*s}", indent - 2, "");
+}
+
+static void dump_vmstate_vmss(FILE *out_file,
+                              const VMStateDescription **subsection,
+                              int indent)
+{
+    if (*subsection != NULL) {
+        dump_vmstate_vmsd(out_file, *subsection, indent, true);
+    }
+}
+
+static void dump_vmstate_vmsd(FILE *out_file,
+                              const VMStateDescription *vmsd, int indent,
+                              bool is_subsection)
+{
+    if (is_subsection) {
+        fprintf(out_file, "%*s{\n", indent, "");
+    } else {
+        fprintf(out_file, "%*s\"%s\": {\n", indent, "", "Description");
+    }
+    indent += 2;
+    fprintf(out_file, "%*s\"name\": \"%s\",\n", indent, "", vmsd->name);
+    fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "",
+            vmsd->version_id);
+    fprintf(out_file, "%*s\"minimum_version_id\": %d", indent, "",
+            vmsd->minimum_version_id);
+    if (vmsd->fields != NULL) {
+        const VMStateField *field = vmsd->fields;
+        bool first;
+
+        fprintf(out_file, ",\n%*s\"Fields\": [\n", indent, "");
+        first = true;
+        while (field->name != NULL) {
+            if (field->flags & VMS_MUST_EXIST) {
+                /* Ignore VMSTATE_VALIDATE bits; these don't get migrated */
+                field++;
+                continue;
+            }
+            if (!first) {
+                fprintf(out_file, ",\n");
+            }
+            dump_vmstate_vmsf(out_file, field, indent + 2);
+            field++;
+            first = false;
+        }
+        fprintf(out_file, "\n%*s]", indent, "");
+    }
+    if (vmsd->subsections != NULL) {
+        const VMStateDescription **subsection = vmsd->subsections;
+        bool first;
+
+        fprintf(out_file, ",\n%*s\"Subsections\": [\n", indent, "");
+        first = true;
+        while (*subsection != NULL) {
+            if (!first) {
+                fprintf(out_file, ",\n");
+            }
+            dump_vmstate_vmss(out_file, subsection, indent + 2);
+            subsection++;
+            first = false;
+        }
+        fprintf(out_file, "\n%*s]", indent, "");
+    }
+    fprintf(out_file, "\n%*s}", indent - 2, "");
+}
+
+static void dump_machine_type(FILE *out_file)
+{
+    MachineClass *mc;
+
+    mc = MACHINE_GET_CLASS(current_machine);
+
+    fprintf(out_file, "  \"vmschkmachine\": {\n");
+    fprintf(out_file, "    \"Name\": \"%s\"\n", mc->name);
+    fprintf(out_file, "  },\n");
+}
+
+void dump_vmstate_json_to_file(FILE *out_file)
+{
+    GSList *list, *elt;
+    bool first;
+
+    fprintf(out_file, "{\n");
+    dump_machine_type(out_file);
+
+    first = true;
+    list = object_class_get_list(TYPE_DEVICE, true);
+    for (elt = list; elt; elt = elt->next) {
+        DeviceClass *dc = OBJECT_CLASS_CHECK(DeviceClass, elt->data,
+                                             TYPE_DEVICE);
+        const char *name;
+        int indent = 2;
+
+        if (!dc->vmsd) {
+            continue;
+        }
+
+        if (!first) {
+            fprintf(out_file, ",\n");
+        }
+        name = object_class_get_name(OBJECT_CLASS(dc));
+        fprintf(out_file, "%*s\"%s\": {\n", indent, "", name);
+        indent += 2;
+        fprintf(out_file, "%*s\"Name\": \"%s\",\n", indent, "", name);
+        fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "",
+                dc->vmsd->version_id);
+        fprintf(out_file, "%*s\"minimum_version_id\": %d,\n", indent, "",
+                dc->vmsd->minimum_version_id);
+
+        dump_vmstate_vmsd(out_file, dc->vmsd, indent, false);
+
+        fprintf(out_file, "\n%*s}", indent - 2, "");
+        first = false;
+    }
+    fprintf(out_file, "\n}\n");
+    fclose(out_file);
+}
+
+static int calculate_new_instance_id(const char *idstr)
+{
+    SaveStateEntry *se;
+    int instance_id = 0;
+
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (strcmp(idstr, se->idstr) == 0
+            && instance_id <= se->instance_id) {
+            instance_id = se->instance_id + 1;
+        }
+    }
+    return instance_id;
+}
+
+static int calculate_compat_instance_id(const char *idstr)
+{
+    SaveStateEntry *se;
+    int instance_id = 0;
+
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (!se->compat) {
+            continue;
+        }
+
+        if (strcmp(idstr, se->compat->idstr) == 0
+            && instance_id <= se->compat->instance_id) {
+            instance_id = se->compat->instance_id + 1;
+        }
+    }
+    return instance_id;
+}
+
+/* TODO: Individual devices generally have very little idea about the rest
+   of the system, so instance_id should be removed/replaced.
+   Meanwhile pass -1 as instance_id if you do not already have a clearly
+   distinguishing id for all instances of your device class. */
+int register_savevm_live(DeviceState *dev,
+                         const char *idstr,
+                         int instance_id,
+                         int version_id,
+                         SaveVMHandlers *ops,
+                         void *opaque)
+{
+    SaveStateEntry *se;
+
+    se = g_new0(SaveStateEntry, 1);
+    se->version_id = version_id;
+    se->section_id = savevm_state.global_section_id++;
+    se->ops = ops;
+    se->opaque = opaque;
+    se->vmsd = NULL;
+    /* if this is a live_savem then set is_ram */
+    if (ops->save_live_setup != NULL) {
+        se->is_ram = 1;
+    }
+
+    if (dev) {
+        char *id = qdev_get_dev_path(dev);
+        if (id) {
+            pstrcpy(se->idstr, sizeof(se->idstr), id);
+            pstrcat(se->idstr, sizeof(se->idstr), "/");
+            g_free(id);
+
+            se->compat = g_new0(CompatEntry, 1);
+            pstrcpy(se->compat->idstr, sizeof(se->compat->idstr), idstr);
+            se->compat->instance_id = instance_id == -1 ?
+                         calculate_compat_instance_id(idstr) : instance_id;
+            instance_id = -1;
+        }
+    }
+    pstrcat(se->idstr, sizeof(se->idstr), idstr);
+
+    if (instance_id == -1) {
+        se->instance_id = calculate_new_instance_id(se->idstr);
+    } else {
+        se->instance_id = instance_id;
+    }
+    assert(!se->compat || se->instance_id == 0);
+    /* add at the end of list */
+    QTAILQ_INSERT_TAIL(&savevm_state.handlers, se, entry);
+    return 0;
+}
+
+int register_savevm(DeviceState *dev,
+                    const char *idstr,
+                    int instance_id,
+                    int version_id,
+                    SaveStateHandler *save_state,
+                    LoadStateHandler *load_state,
+                    void *opaque)
+{
+    SaveVMHandlers *ops = g_new0(SaveVMHandlers, 1);
+    ops->save_state = save_state;
+    ops->load_state = load_state;
+    return register_savevm_live(dev, idstr, instance_id, version_id,
+                                ops, opaque);
+}
+
+void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque)
+{
+    SaveStateEntry *se, *new_se;
+    char id[256] = "";
+
+    if (dev) {
+        char *path = qdev_get_dev_path(dev);
+        if (path) {
+            pstrcpy(id, sizeof(id), path);
+            pstrcat(id, sizeof(id), "/");
+            g_free(path);
+        }
+    }
+    pstrcat(id, sizeof(id), idstr);
+
+    QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) {
+        if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) {
+            QTAILQ_REMOVE(&savevm_state.handlers, se, entry);
+            g_free(se->compat);
+            g_free(se->ops);
+            g_free(se);
+        }
+    }
+}
+
+int vmstate_register_with_alias_id(DeviceState *dev, int instance_id,
+                                   const VMStateDescription *vmsd,
+                                   void *opaque, int alias_id,
+                                   int required_for_version)
+{
+    SaveStateEntry *se;
+
+    /* If this triggers, alias support can be dropped for the vmsd. */
+    assert(alias_id == -1 || required_for_version >= vmsd->minimum_version_id);
+
+    se = g_new0(SaveStateEntry, 1);
+    se->version_id = vmsd->version_id;
+    se->section_id = savevm_state.global_section_id++;
+    se->opaque = opaque;
+    se->vmsd = vmsd;
+    se->alias_id = alias_id;
+
+    if (dev) {
+        char *id = qdev_get_dev_path(dev);
+        if (id) {
+            pstrcpy(se->idstr, sizeof(se->idstr), id);
+            pstrcat(se->idstr, sizeof(se->idstr), "/");
+            g_free(id);
+
+            se->compat = g_new0(CompatEntry, 1);
+            pstrcpy(se->compat->idstr, sizeof(se->compat->idstr), vmsd->name);
+            se->compat->instance_id = instance_id == -1 ?
+                         calculate_compat_instance_id(vmsd->name) : instance_id;
+            instance_id = -1;
+        }
+    }
+    pstrcat(se->idstr, sizeof(se->idstr), vmsd->name);
+
+    if (instance_id == -1) {
+        se->instance_id = calculate_new_instance_id(se->idstr);
+    } else {
+        se->instance_id = instance_id;
+    }
+    assert(!se->compat || se->instance_id == 0);
+    /* add at the end of list */
+    QTAILQ_INSERT_TAIL(&savevm_state.handlers, se, entry);
+    return 0;
+}
+
+void vmstate_unregister(DeviceState *dev, const VMStateDescription *vmsd,
+                        void *opaque)
+{
+    SaveStateEntry *se, *new_se;
+
+    QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) {
+        if (se->vmsd == vmsd && se->opaque == opaque) {
+            QTAILQ_REMOVE(&savevm_state.handlers, se, entry);
+            g_free(se->compat);
+            g_free(se);
+        }
+    }
+}
+
+static int vmstate_load(QEMUFile *f, SaveStateEntry *se, int version_id)
+{
+    trace_vmstate_load(se->idstr, se->vmsd ? se->vmsd->name : "(old)");
+    if (!se->vmsd) {         /* Old style */
+        return se->ops->load_state(f, se->opaque, version_id);
+    }
+    return vmstate_load_state(f, se->vmsd, se->opaque, version_id);
+}
+
+static void vmstate_save_old_style(QEMUFile *f, SaveStateEntry *se, QJSON *vmdesc)
+{
+    int64_t old_offset, size;
+
+    old_offset = qemu_ftell_fast(f);
+    se->ops->save_state(f, se->opaque);
+    size = qemu_ftell_fast(f) - old_offset;
+
+    if (vmdesc) {
+        json_prop_int(vmdesc, "size", size);
+        json_start_array(vmdesc, "fields");
+        json_start_object(vmdesc, NULL);
+        json_prop_str(vmdesc, "name", "data");
+        json_prop_int(vmdesc, "size", size);
+        json_prop_str(vmdesc, "type", "buffer");
+        json_end_object(vmdesc);
+        json_end_array(vmdesc);
+    }
+}
+
+static void vmstate_save(QEMUFile *f, SaveStateEntry *se, QJSON *vmdesc)
+{
+    trace_vmstate_save(se->idstr, se->vmsd ? se->vmsd->name : "(old)");
+    if (!se->vmsd) {
+        vmstate_save_old_style(f, se, vmdesc);
+        return;
+    }
+    vmstate_save_state(f, se->vmsd, se->opaque, vmdesc);
+}
+
+void savevm_skip_section_footers(void)
+{
+    skip_section_footers = true;
+}
+
+/*
+ * Write the header for device section (QEMU_VM_SECTION START/END/PART/FULL)
+ */
+static void save_section_header(QEMUFile *f, SaveStateEntry *se,
+                                uint8_t section_type)
+{
+    qemu_put_byte(f, section_type);
+    qemu_put_be32(f, se->section_id);
+
+    if (section_type == QEMU_VM_SECTION_FULL ||
+        section_type == QEMU_VM_SECTION_START) {
+        /* ID string */
+        size_t len = strlen(se->idstr);
+        qemu_put_byte(f, len);
+        qemu_put_buffer(f, (uint8_t *)se->idstr, len);
+
+        qemu_put_be32(f, se->instance_id);
+        qemu_put_be32(f, se->version_id);
+    }
+}
+
+/*
+ * Write a footer onto device sections that catches cases misformatted device
+ * sections.
+ */
+static void save_section_footer(QEMUFile *f, SaveStateEntry *se)
+{
+    if (!skip_section_footers) {
+        qemu_put_byte(f, QEMU_VM_SECTION_FOOTER);
+        qemu_put_be32(f, se->section_id);
+    }
+}
+
+/**
+ * qemu_savevm_command_send: Send a 'QEMU_VM_COMMAND' type element with the
+ *                           command and associated data.
+ *
+ * @f: File to send command on
+ * @command: Command type to send
+ * @len: Length of associated data
+ * @data: Data associated with command.
+ */
+void qemu_savevm_command_send(QEMUFile *f,
+                              enum qemu_vm_cmd command,
+                              uint16_t len,
+                              uint8_t *data)
+{
+    trace_savevm_command_send(command, len);
+    qemu_put_byte(f, QEMU_VM_COMMAND);
+    qemu_put_be16(f, (uint16_t)command);
+    qemu_put_be16(f, len);
+    qemu_put_buffer(f, data, len);
+    qemu_fflush(f);
+}
+
+void qemu_savevm_send_ping(QEMUFile *f, uint32_t value)
+{
+    uint32_t buf;
+
+    trace_savevm_send_ping(value);
+    buf = cpu_to_be32(value);
+    qemu_savevm_command_send(f, MIG_CMD_PING, sizeof(value), (uint8_t *)&buf);
+}
+
+void qemu_savevm_send_open_return_path(QEMUFile *f)
+{
+    trace_savevm_send_open_return_path();
+    qemu_savevm_command_send(f, MIG_CMD_OPEN_RETURN_PATH, 0, NULL);
+}
+
+/* We have a buffer of data to send; we don't want that all to be loaded
+ * by the command itself, so the command contains just the length of the
+ * extra buffer that we then send straight after it.
+ * TODO: Must be a better way to organise that
+ *
+ * Returns:
+ *    0 on success
+ *    -ve on error
+ */
+int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb)
+{
+    size_t cur_iov;
+    size_t len = qsb_get_length(qsb);
+    uint32_t tmp;
+
+    if (len > MAX_VM_CMD_PACKAGED_SIZE) {
+        error_report("%s: Unreasonably large packaged state: %zu",
+                     __func__, len);
+        return -1;
+    }
+
+    tmp = cpu_to_be32(len);
+
+    trace_qemu_savevm_send_packaged();
+    qemu_savevm_command_send(f, MIG_CMD_PACKAGED, 4, (uint8_t *)&tmp);
+
+    /* all the data follows (concatinating the iov's) */
+    for (cur_iov = 0; cur_iov < qsb->n_iov; cur_iov++) {
+        /* The iov entries are partially filled */
+        size_t towrite = MIN(qsb->iov[cur_iov].iov_len, len);
+        len -= towrite;
+
+        if (!towrite) {
+            break;
+        }
+
+        qemu_put_buffer(f, qsb->iov[cur_iov].iov_base, towrite);
+    }
+
+    return 0;
+}
+
+/* Send prior to any postcopy transfer */
+void qemu_savevm_send_postcopy_advise(QEMUFile *f)
+{
+    uint64_t tmp[2];
+    tmp[0] = cpu_to_be64(getpagesize());
+    tmp[1] = cpu_to_be64(1ul << qemu_target_page_bits());
+
+    trace_qemu_savevm_send_postcopy_advise();
+    qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_ADVISE, 16, (uint8_t *)tmp);
+}
+
+/* Sent prior to starting the destination running in postcopy, discard pages
+ * that have already been sent but redirtied on the source.
+ * CMD_POSTCOPY_RAM_DISCARD consist of:
+ *      byte   version (0)
+ *      byte   Length of name field (not including 0)
+ *  n x byte   RAM block name
+ *      byte   0 terminator (just for safety)
+ *  n x        Byte ranges within the named RAMBlock
+ *      be64   Start of the range
+ *      be64   Length
+ *
+ *  name:  RAMBlock name that these entries are part of
+ *  len: Number of page entries
+ *  start_list: 'len' addresses
+ *  length_list: 'len' addresses
+ *
+ */
+void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name,
+                                           uint16_t len,
+                                           uint64_t *start_list,
+                                           uint64_t *length_list)
+{
+    uint8_t *buf;
+    uint16_t tmplen;
+    uint16_t t;
+    size_t name_len = strlen(name);
+
+    trace_qemu_savevm_send_postcopy_ram_discard(name, len);
+    assert(name_len < 256);
+    buf = g_malloc0(1 + 1 + name_len + 1 + (8 + 8) * len);
+    buf[0] = postcopy_ram_discard_version;
+    buf[1] = name_len;
+    memcpy(buf + 2, name, name_len);
+    tmplen = 2 + name_len;
+    buf[tmplen++] = '\0';
+
+    for (t = 0; t < len; t++) {
+        cpu_to_be64w((uint64_t *)(buf + tmplen), start_list[t]);
+        tmplen += 8;
+        cpu_to_be64w((uint64_t *)(buf + tmplen), length_list[t]);
+        tmplen += 8;
+    }
+    qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RAM_DISCARD, tmplen, buf);
+    g_free(buf);
+}
+
+/* Get the destination into a state where it can receive postcopy data. */
+void qemu_savevm_send_postcopy_listen(QEMUFile *f)
+{
+    trace_savevm_send_postcopy_listen();
+    qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_LISTEN, 0, NULL);
+}
+
+/* Kick the destination into running */
+void qemu_savevm_send_postcopy_run(QEMUFile *f)
+{
+    trace_savevm_send_postcopy_run();
+    qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RUN, 0, NULL);
+}
+
+bool qemu_savevm_state_blocked(Error **errp)
+{
+    SaveStateEntry *se;
+
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (se->vmsd && se->vmsd->unmigratable) {
+            error_setg(errp, "State blocked by non-migratable device '%s'",
+                       se->idstr);
+            return true;
+        }
+    }
+    return false;
+}
+
+static bool enforce_config_section(void)
+{
+    MachineState *machine = MACHINE(qdev_get_machine());
+    return machine->enforce_config_section;
+}
+
+void qemu_savevm_state_header(QEMUFile *f)
+{
+    trace_savevm_state_header();
+    qemu_put_be32(f, QEMU_VM_FILE_MAGIC);
+    qemu_put_be32(f, QEMU_VM_FILE_VERSION);
+
+    if (!savevm_state.skip_configuration || enforce_config_section()) {
+        qemu_put_byte(f, QEMU_VM_CONFIGURATION);
+        vmstate_save_state(f, &vmstate_configuration, &savevm_state, 0);
+    }
+
+}
+
+void qemu_savevm_state_begin(QEMUFile *f,
+                             const MigrationParams *params)
+{
+    SaveStateEntry *se;
+    int ret;
+
+    trace_savevm_state_begin();
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (!se->ops || !se->ops->set_params) {
+            continue;
+        }
+        se->ops->set_params(params, se->opaque);
+    }
+
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (!se->ops || !se->ops->save_live_setup) {
+            continue;
+        }
+        if (se->ops && se->ops->is_active) {
+            if (!se->ops->is_active(se->opaque)) {
+                continue;
+            }
+        }
+        save_section_header(f, se, QEMU_VM_SECTION_START);
+
+        ret = se->ops->save_live_setup(f, se->opaque);
+        save_section_footer(f, se);
+        if (ret < 0) {
+            qemu_file_set_error(f, ret);
+            break;
+        }
+    }
+}
+
+/*
+ * this function has three return values:
+ *   negative: there was one error, and we have -errno.
+ *   0 : We haven't finished, caller have to go again
+ *   1 : We have finished, we can go to complete phase
+ */
+int qemu_savevm_state_iterate(QEMUFile *f, bool postcopy)
+{
+    SaveStateEntry *se;
+    int ret = 1;
+
+    trace_savevm_state_iterate();
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (!se->ops || !se->ops->save_live_iterate) {
+            continue;
+        }
+        if (se->ops && se->ops->is_active) {
+            if (!se->ops->is_active(se->opaque)) {
+                continue;
+            }
+        }
+        /*
+         * In the postcopy phase, any device that doesn't know how to
+         * do postcopy should have saved it's state in the _complete
+         * call that's already run, it might get confused if we call
+         * iterate afterwards.
+         */
+        if (postcopy && !se->ops->save_live_complete_postcopy) {
+            continue;
+        }
+        if (qemu_file_rate_limit(f)) {
+            return 0;
+        }
+        trace_savevm_section_start(se->idstr, se->section_id);
+
+        save_section_header(f, se, QEMU_VM_SECTION_PART);
+
+        ret = se->ops->save_live_iterate(f, se->opaque);
+        trace_savevm_section_end(se->idstr, se->section_id, ret);
+        save_section_footer(f, se);
+
+        if (ret < 0) {
+            qemu_file_set_error(f, ret);
+        }
+        if (ret <= 0) {
+            /* Do not proceed to the next vmstate before this one reported
+               completion of the current stage. This serializes the migration
+               and reduces the probability that a faster changing state is
+               synchronized over and over again. */
+            break;
+        }
+    }
+    return ret;
+}
+
+static bool should_send_vmdesc(void)
+{
+    MachineState *machine = MACHINE(qdev_get_machine());
+    bool in_postcopy = migration_in_postcopy(migrate_get_current());
+    return !machine->suppress_vmdesc && !in_postcopy;
+}
+
+/*
+ * Calls the save_live_complete_postcopy methods
+ * causing the last few pages to be sent immediately and doing any associated
+ * cleanup.
+ * Note postcopy also calls qemu_savevm_state_complete_precopy to complete
+ * all the other devices, but that happens at the point we switch to postcopy.
+ */
+void qemu_savevm_state_complete_postcopy(QEMUFile *f)
+{
+    SaveStateEntry *se;
+    int ret;
+
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (!se->ops || !se->ops->save_live_complete_postcopy) {
+            continue;
+        }
+        if (se->ops && se->ops->is_active) {
+            if (!se->ops->is_active(se->opaque)) {
+                continue;
+            }
+        }
+        trace_savevm_section_start(se->idstr, se->section_id);
+        /* Section type */
+        qemu_put_byte(f, QEMU_VM_SECTION_END);
+        qemu_put_be32(f, se->section_id);
+
+        ret = se->ops->save_live_complete_postcopy(f, se->opaque);
+        trace_savevm_section_end(se->idstr, se->section_id, ret);
+        save_section_footer(f, se);
+        if (ret < 0) {
+            qemu_file_set_error(f, ret);
+            return;
+        }
+    }
+
+    qemu_put_byte(f, QEMU_VM_EOF);
+    qemu_fflush(f);
+}
+
+void qemu_savevm_state_complete_precopy(QEMUFile *f, bool iterable_only)
+{
+    QJSON *vmdesc;
+    int vmdesc_len;
+    SaveStateEntry *se;
+    int ret;
+    bool in_postcopy = migration_in_postcopy(migrate_get_current());
+
+    trace_savevm_state_complete_precopy();
+
+    cpu_synchronize_all_states();
+
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (!se->ops ||
+            (in_postcopy && se->ops->save_live_complete_postcopy) ||
+            (in_postcopy && !iterable_only) ||
+            !se->ops->save_live_complete_precopy) {
+            continue;
+        }
+
+        if (se->ops && se->ops->is_active) {
+            if (!se->ops->is_active(se->opaque)) {
+                continue;
+            }
+        }
+        trace_savevm_section_start(se->idstr, se->section_id);
+
+        save_section_header(f, se, QEMU_VM_SECTION_END);
+
+        ret = se->ops->save_live_complete_precopy(f, se->opaque);
+        trace_savevm_section_end(se->idstr, se->section_id, ret);
+        save_section_footer(f, se);
+        if (ret < 0) {
+            qemu_file_set_error(f, ret);
+            return;
+        }
+    }
+
+    if (iterable_only) {
+        return;
+    }
+
+    vmdesc = qjson_new();
+    json_prop_int(vmdesc, "page_size", TARGET_PAGE_SIZE);
+    json_start_array(vmdesc, "devices");
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+
+        if ((!se->ops || !se->ops->save_state) && !se->vmsd) {
+            continue;
+        }
+        if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) {
+            trace_savevm_section_skip(se->idstr, se->section_id);
+            continue;
+        }
+
+        trace_savevm_section_start(se->idstr, se->section_id);
+
+        json_start_object(vmdesc, NULL);
+        json_prop_str(vmdesc, "name", se->idstr);
+        json_prop_int(vmdesc, "instance_id", se->instance_id);
+
+        save_section_header(f, se, QEMU_VM_SECTION_FULL);
+
+        vmstate_save(f, se, vmdesc);
+
+        json_end_object(vmdesc);
+        trace_savevm_section_end(se->idstr, se->section_id, 0);
+        save_section_footer(f, se);
+    }
+
+    if (!in_postcopy) {
+        /* Postcopy stream will still be going */
+        qemu_put_byte(f, QEMU_VM_EOF);
+    }
+
+    json_end_array(vmdesc);
+    qjson_finish(vmdesc);
+    vmdesc_len = strlen(qjson_get_str(vmdesc));
+
+    if (should_send_vmdesc()) {
+        qemu_put_byte(f, QEMU_VM_VMDESCRIPTION);
+        qemu_put_be32(f, vmdesc_len);
+        qemu_put_buffer(f, (uint8_t *)qjson_get_str(vmdesc), vmdesc_len);
+    }
+    object_unref(OBJECT(vmdesc));
+
+    qemu_fflush(f);
+}
+
+/* Give an estimate of the amount left to be transferred,
+ * the result is split into the amount for units that can and
+ * for units that can't do postcopy.
+ */
+void qemu_savevm_state_pending(QEMUFile *f, uint64_t max_size,
+                               uint64_t *res_non_postcopiable,
+                               uint64_t *res_postcopiable)
+{
+    SaveStateEntry *se;
+
+    *res_non_postcopiable = 0;
+    *res_postcopiable = 0;
+
+
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (!se->ops || !se->ops->save_live_pending) {
+            continue;
+        }
+        if (se->ops && se->ops->is_active) {
+            if (!se->ops->is_active(se->opaque)) {
+                continue;
+            }
+        }
+        se->ops->save_live_pending(f, se->opaque, max_size,
+                                   res_non_postcopiable, res_postcopiable);
+    }
+}
+
+void qemu_savevm_state_cleanup(void)
+{
+    SaveStateEntry *se;
+
+    trace_savevm_state_cleanup();
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (se->ops && se->ops->cleanup) {
+            se->ops->cleanup(se->opaque);
+        }
+    }
+}
+
+static int qemu_savevm_state(QEMUFile *f, Error **errp)
+{
+    int ret;
+    MigrationParams params = {
+        .blk = 0,
+        .shared = 0
+    };
+    MigrationState *ms = migrate_init(&params);
+    ms->file = f;
+
+    if (qemu_savevm_state_blocked(errp)) {
+        return -EINVAL;
+    }
+
+    qemu_mutex_unlock_iothread();
+    qemu_savevm_state_header(f);
+    qemu_savevm_state_begin(f, &params);
+    qemu_mutex_lock_iothread();
+
+    while (qemu_file_get_error(f) == 0) {
+        if (qemu_savevm_state_iterate(f, false) > 0) {
+            break;
+        }
+    }
+
+    ret = qemu_file_get_error(f);
+    if (ret == 0) {
+        qemu_savevm_state_complete_precopy(f, false);
+        ret = qemu_file_get_error(f);
+    }
+    qemu_savevm_state_cleanup();
+    if (ret != 0) {
+        error_setg_errno(errp, -ret, "Error while writing VM state");
+    }
+    return ret;
+}
+
+static int qemu_save_device_state(QEMUFile *f)
+{
+    SaveStateEntry *se;
+
+    qemu_put_be32(f, QEMU_VM_FILE_MAGIC);
+    qemu_put_be32(f, QEMU_VM_FILE_VERSION);
+
+    cpu_synchronize_all_states();
+
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (se->is_ram) {
+            continue;
+        }
+        if ((!se->ops || !se->ops->save_state) && !se->vmsd) {
+            continue;
+        }
+        if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) {
+            continue;
+        }
+
+        save_section_header(f, se, QEMU_VM_SECTION_FULL);
+
+        vmstate_save(f, se, NULL);
+
+        save_section_footer(f, se);
+    }
+
+    qemu_put_byte(f, QEMU_VM_EOF);
+
+    return qemu_file_get_error(f);
+}
+
+static SaveStateEntry *find_se(const char *idstr, int instance_id)
+{
+    SaveStateEntry *se;
+
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (!strcmp(se->idstr, idstr) &&
+            (instance_id == se->instance_id ||
+             instance_id == se->alias_id))
+            return se;
+        /* Migrating from an older version? */
+        if (strstr(se->idstr, idstr) && se->compat) {
+            if (!strcmp(se->compat->idstr, idstr) &&
+                (instance_id == se->compat->instance_id ||
+                 instance_id == se->alias_id))
+                return se;
+        }
+    }
+    return NULL;
+}
+
+enum LoadVMExitCodes {
+    /* Allow a command to quit all layers of nested loadvm loops */
+    LOADVM_QUIT     =  1,
+};
+
+static int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis);
+
+/* ------ incoming postcopy messages ------ */
+/* 'advise' arrives before any transfers just to tell us that a postcopy
+ * *might* happen - it might be skipped if precopy transferred everything
+ * quickly.
+ */
+static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis)
+{
+    PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_ADVISE);
+    uint64_t remote_hps, remote_tps;
+
+    trace_loadvm_postcopy_handle_advise();
+    if (ps != POSTCOPY_INCOMING_NONE) {
+        error_report("CMD_POSTCOPY_ADVISE in wrong postcopy state (%d)", ps);
+        return -1;
+    }
+
+    if (!postcopy_ram_supported_by_host()) {
+        return -1;
+    }
+
+    remote_hps = qemu_get_be64(mis->from_src_file);
+    if (remote_hps != getpagesize())  {
+        /*
+         * Some combinations of mismatch are probably possible but it gets
+         * a bit more complicated.  In particular we need to place whole
+         * host pages on the dest at once, and we need to ensure that we
+         * handle dirtying to make sure we never end up sending part of
+         * a hostpage on it's own.
+         */
+        error_report("Postcopy needs matching host page sizes (s=%d d=%d)",
+                     (int)remote_hps, getpagesize());
+        return -1;
+    }
+
+    remote_tps = qemu_get_be64(mis->from_src_file);
+    if (remote_tps != (1ul << qemu_target_page_bits())) {
+        /*
+         * Again, some differences could be dealt with, but for now keep it
+         * simple.
+         */
+        error_report("Postcopy needs matching target page sizes (s=%d d=%d)",
+                     (int)remote_tps, 1 << qemu_target_page_bits());
+        return -1;
+    }
+
+    if (ram_postcopy_incoming_init(mis)) {
+        return -1;
+    }
+
+    postcopy_state_set(POSTCOPY_INCOMING_ADVISE);
+
+    return 0;
+}
+
+/* After postcopy we will be told to throw some pages away since they're
+ * dirty and will have to be demand fetched.  Must happen before CPU is
+ * started.
+ * There can be 0..many of these messages, each encoding multiple pages.
+ */
+static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis,
+                                              uint16_t len)
+{
+    int tmp;
+    char ramid[256];
+    PostcopyState ps = postcopy_state_get();
+
+    trace_loadvm_postcopy_ram_handle_discard();
+
+    switch (ps) {
+    case POSTCOPY_INCOMING_ADVISE:
+        /* 1st discard */
+        tmp = postcopy_ram_prepare_discard(mis);
+        if (tmp) {
+            return tmp;
+        }
+        break;
+
+    case POSTCOPY_INCOMING_DISCARD:
+        /* Expected state */
+        break;
+
+    default:
+        error_report("CMD_POSTCOPY_RAM_DISCARD in wrong postcopy state (%d)",
+                     ps);
+        return -1;
+    }
+    /* We're expecting a
+     *    Version (0)
+     *    a RAM ID string (length byte, name, 0 term)
+     *    then at least 1 16 byte chunk
+    */
+    if (len < (1 + 1 + 1 + 1 + 2 * 8)) {
+        error_report("CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len);
+        return -1;
+    }
+
+    tmp = qemu_get_byte(mis->from_src_file);
+    if (tmp != postcopy_ram_discard_version) {
+        error_report("CMD_POSTCOPY_RAM_DISCARD invalid version (%d)", tmp);
+        return -1;
+    }
+
+    if (!qemu_get_counted_string(mis->from_src_file, ramid)) {
+        error_report("CMD_POSTCOPY_RAM_DISCARD Failed to read RAMBlock ID");
+        return -1;
+    }
+    tmp = qemu_get_byte(mis->from_src_file);
+    if (tmp != 0) {
+        error_report("CMD_POSTCOPY_RAM_DISCARD missing nil (%d)", tmp);
+        return -1;
+    }
+
+    len -= 3 + strlen(ramid);
+    if (len % 16) {
+        error_report("CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len);
+        return -1;
+    }
+    trace_loadvm_postcopy_ram_handle_discard_header(ramid, len);
+    while (len) {
+        uint64_t start_addr, block_length;
+        start_addr = qemu_get_be64(mis->from_src_file);
+        block_length = qemu_get_be64(mis->from_src_file);
+
+        len -= 16;
+        int ret = ram_discard_range(mis, ramid, start_addr,
+                                    block_length);
+        if (ret) {
+            return ret;
+        }
+    }
+    trace_loadvm_postcopy_ram_handle_discard_end();
+
+    return 0;
+}
+
+/*
+ * Triggered by a postcopy_listen command; this thread takes over reading
+ * the input stream, leaving the main thread free to carry on loading the rest
+ * of the device state (from RAM).
+ * (TODO:This could do with being in a postcopy file - but there again it's
+ * just another input loop, not that postcopy specific)
+ */
+static void *postcopy_ram_listen_thread(void *opaque)
+{
+    QEMUFile *f = opaque;
+    MigrationIncomingState *mis = migration_incoming_get_current();
+    int load_res;
+
+    qemu_sem_post(&mis->listen_thread_sem);
+    trace_postcopy_ram_listen_thread_start();
+
+    /*
+     * Because we're a thread and not a coroutine we can't yield
+     * in qemu_file, and thus we must be blocking now.
+     */
+    qemu_file_set_blocking(f, true);
+    load_res = qemu_loadvm_state_main(f, mis);
+    /* And non-blocking again so we don't block in any cleanup */
+    qemu_file_set_blocking(f, false);
+
+    trace_postcopy_ram_listen_thread_exit();
+    if (load_res < 0) {
+        error_report("%s: loadvm failed: %d", __func__, load_res);
+        qemu_file_set_error(f, load_res);
+    } else {
+        /*
+         * This looks good, but it's possible that the device loading in the
+         * main thread hasn't finished yet, and so we might not be in 'RUN'
+         * state yet; wait for the end of the main thread.
+         */
+        qemu_event_wait(&mis->main_thread_load_event);
+    }
+    postcopy_ram_incoming_cleanup(mis);
+    /*
+     * If everything has worked fine, then the main thread has waited
+     * for us to start, and we're the last use of the mis.
+     * (If something broke then qemu will have to exit anyway since it's
+     * got a bad migration state).
+     */
+    migration_incoming_state_destroy();
+
+    if (load_res < 0) {
+        /*
+         * If something went wrong then we have a bad state so exit;
+         * depending how far we got it might be possible at this point
+         * to leave the guest running and fire MCEs for pages that never
+         * arrived as a desperate recovery step.
+         */
+        exit(EXIT_FAILURE);
+    }
+
+    return NULL;
+}
+
+/* After this message we must be able to immediately receive postcopy data */
+static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis)
+{
+    PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_LISTENING);
+    trace_loadvm_postcopy_handle_listen();
+    if (ps != POSTCOPY_INCOMING_ADVISE && ps != POSTCOPY_INCOMING_DISCARD) {
+        error_report("CMD_POSTCOPY_LISTEN in wrong postcopy state (%d)", ps);
+        return -1;
+    }
+    if (ps == POSTCOPY_INCOMING_ADVISE) {
+        /*
+         * A rare case, we entered listen without having to do any discards,
+         * so do the setup that's normally done at the time of the 1st discard.
+         */
+        postcopy_ram_prepare_discard(mis);
+    }
+
+    /*
+     * Sensitise RAM - can now generate requests for blocks that don't exist
+     * However, at this point the CPU shouldn't be running, and the IO
+     * shouldn't be doing anything yet so don't actually expect requests
+     */
+    if (postcopy_ram_enable_notify(mis)) {
+        return -1;
+    }
+
+    if (mis->have_listen_thread) {
+        error_report("CMD_POSTCOPY_RAM_LISTEN already has a listen thread");
+        return -1;
+    }
+
+    mis->have_listen_thread = true;
+    /* Start up the listening thread and wait for it to signal ready */
+    qemu_sem_init(&mis->listen_thread_sem, 0);
+    qemu_thread_create(&mis->listen_thread, "postcopy/listen",
+                       postcopy_ram_listen_thread, mis->from_src_file,
+                       QEMU_THREAD_JOINABLE);
+    qemu_sem_wait(&mis->listen_thread_sem);
+    qemu_sem_destroy(&mis->listen_thread_sem);
+
+    return 0;
+}
+
+/* After all discards we can start running and asking for pages */
+static int loadvm_postcopy_handle_run(MigrationIncomingState *mis)
+{
+    PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_RUNNING);
+    Error *local_err = NULL;
+
+    trace_loadvm_postcopy_handle_run();
+    if (ps != POSTCOPY_INCOMING_LISTENING) {
+        error_report("CMD_POSTCOPY_RUN in wrong postcopy state (%d)", ps);
+        return -1;
+    }
+
+    /* TODO we should move all of this lot into postcopy_ram.c or a shared code
+     * in migration.c
+     */
+    cpu_synchronize_all_post_init();
+
+    qemu_announce_self();
+
+    /* Make sure all file formats flush their mutable metadata */
+    bdrv_invalidate_cache_all(&local_err);
+    if (local_err) {
+        error_report_err(local_err);
+        return -1;
+    }
+
+    trace_loadvm_postcopy_handle_run_cpu_sync();
+    cpu_synchronize_all_post_init();
+
+    trace_loadvm_postcopy_handle_run_vmstart();
+
+    if (autostart) {
+        /* Hold onto your hats, starting the CPU */
+        vm_start();
+    } else {
+        /* leave it paused and let management decide when to start the CPU */
+        runstate_set(RUN_STATE_PAUSED);
+    }
+
+    /* We need to finish reading the stream from the package
+     * and also stop reading anything more from the stream that loaded the
+     * package (since it's now being read by the listener thread).
+     * LOADVM_QUIT will quit all the layers of nested loadvm loops.
+     */
+    return LOADVM_QUIT;
+}
+
+/**
+ * Immediately following this command is a blob of data containing an embedded
+ * chunk of migration stream; read it and load it.
+ *
+ * @mis: Incoming state
+ * @length: Length of packaged data to read
+ *
+ * Returns: Negative values on error
+ *
+ */
+static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis)
+{
+    int ret;
+    uint8_t *buffer;
+    uint32_t length;
+    QEMUSizedBuffer *qsb;
+
+    length = qemu_get_be32(mis->from_src_file);
+    trace_loadvm_handle_cmd_packaged(length);
+
+    if (length > MAX_VM_CMD_PACKAGED_SIZE) {
+        error_report("Unreasonably large packaged state: %u", length);
+        return -1;
+    }
+    buffer = g_malloc0(length);
+    ret = qemu_get_buffer(mis->from_src_file, buffer, (int)length);
+    if (ret != length) {
+        g_free(buffer);
+        error_report("CMD_PACKAGED: Buffer receive fail ret=%d length=%d\n",
+                ret, length);
+        return (ret < 0) ? ret : -EAGAIN;
+    }
+    trace_loadvm_handle_cmd_packaged_received(ret);
+
+    /* Setup a dummy QEMUFile that actually reads from the buffer */
+    qsb = qsb_create(buffer, length);
+    g_free(buffer); /* Because qsb_create copies */
+    if (!qsb) {
+        error_report("Unable to create qsb");
+    }
+    QEMUFile *packf = qemu_bufopen("r", qsb);
+
+    ret = qemu_loadvm_state_main(packf, mis);
+    trace_loadvm_handle_cmd_packaged_main(ret);
+    qemu_fclose(packf);
+    qsb_free(qsb);
+
+    return ret;
+}
+
+/*
+ * Process an incoming 'QEMU_VM_COMMAND'
+ * 0           just a normal return
+ * LOADVM_QUIT All good, but exit the loop
+ * <0          Error
+ */
+static int loadvm_process_command(QEMUFile *f)
+{
+    MigrationIncomingState *mis = migration_incoming_get_current();
+    uint16_t cmd;
+    uint16_t len;
+    uint32_t tmp32;
+
+    cmd = qemu_get_be16(f);
+    len = qemu_get_be16(f);
+
+    trace_loadvm_process_command(cmd, len);
+    if (cmd >= MIG_CMD_MAX || cmd == MIG_CMD_INVALID) {
+        error_report("MIG_CMD 0x%x unknown (len 0x%x)", cmd, len);
+        return -EINVAL;
+    }
+
+    if (mig_cmd_args[cmd].len != -1 && mig_cmd_args[cmd].len != len) {
+        error_report("%s received with bad length - expecting %zu, got %d",
+                     mig_cmd_args[cmd].name,
+                     (size_t)mig_cmd_args[cmd].len, len);
+        return -ERANGE;
+    }
+
+    switch (cmd) {
+    case MIG_CMD_OPEN_RETURN_PATH:
+        if (mis->to_src_file) {
+            error_report("CMD_OPEN_RETURN_PATH called when RP already open");
+            /* Not really a problem, so don't give up */
+            return 0;
+        }
+        mis->to_src_file = qemu_file_get_return_path(f);
+        if (!mis->to_src_file) {
+            error_report("CMD_OPEN_RETURN_PATH failed");
+            return -1;
+        }
+        break;
+
+    case MIG_CMD_PING:
+        tmp32 = qemu_get_be32(f);
+        trace_loadvm_process_command_ping(tmp32);
+        if (!mis->to_src_file) {
+            error_report("CMD_PING (0x%x) received with no return path",
+                         tmp32);
+            return -1;
+        }
+        migrate_send_rp_pong(mis, tmp32);
+        break;
+
+    case MIG_CMD_PACKAGED:
+        return loadvm_handle_cmd_packaged(mis);
+
+    case MIG_CMD_POSTCOPY_ADVISE:
+        return loadvm_postcopy_handle_advise(mis);
+
+    case MIG_CMD_POSTCOPY_LISTEN:
+        return loadvm_postcopy_handle_listen(mis);
+
+    case MIG_CMD_POSTCOPY_RUN:
+        return loadvm_postcopy_handle_run(mis);
+
+    case MIG_CMD_POSTCOPY_RAM_DISCARD:
+        return loadvm_postcopy_ram_handle_discard(mis, len);
+    }
+
+    return 0;
+}
+
+struct LoadStateEntry {
+    QLIST_ENTRY(LoadStateEntry) entry;
+    SaveStateEntry *se;
+    int section_id;
+    int version_id;
+};
+
+/*
+ * Read a footer off the wire and check that it matches the expected section
+ *
+ * Returns: true if the footer was good
+ *          false if there is a problem (and calls error_report to say why)
+ */
+static bool check_section_footer(QEMUFile *f, LoadStateEntry *le)
+{
+    uint8_t read_mark;
+    uint32_t read_section_id;
+
+    if (skip_section_footers) {
+        /* No footer to check */
+        return true;
+    }
+
+    read_mark = qemu_get_byte(f);
+
+    if (read_mark != QEMU_VM_SECTION_FOOTER) {
+        error_report("Missing section footer for %s", le->se->idstr);
+        return false;
+    }
+
+    read_section_id = qemu_get_be32(f);
+    if (read_section_id != le->section_id) {
+        error_report("Mismatched section id in footer for %s -"
+                     " read 0x%x expected 0x%x",
+                     le->se->idstr, read_section_id, le->section_id);
+        return false;
+    }
+
+    /* All good */
+    return true;
+}
+
+void loadvm_free_handlers(MigrationIncomingState *mis)
+{
+    LoadStateEntry *le, *new_le;
+
+    QLIST_FOREACH_SAFE(le, &mis->loadvm_handlers, entry, new_le) {
+        QLIST_REMOVE(le, entry);
+        g_free(le);
+    }
+}
+
+static int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis)
+{
+    uint8_t section_type;
+    int ret;
+
+    while ((section_type = qemu_get_byte(f)) != QEMU_VM_EOF) {
+        uint32_t instance_id, version_id, section_id;
+        SaveStateEntry *se;
+        LoadStateEntry *le;
+        char idstr[256];
+
+        trace_qemu_loadvm_state_section(section_type);
+        switch (section_type) {
+        case QEMU_VM_SECTION_START:
+        case QEMU_VM_SECTION_FULL:
+            /* Read section start */
+            section_id = qemu_get_be32(f);
+            if (!qemu_get_counted_string(f, idstr)) {
+                error_report("Unable to read ID string for section %u",
+                            section_id);
+                return -EINVAL;
+            }
+            instance_id = qemu_get_be32(f);
+            version_id = qemu_get_be32(f);
+
+            trace_qemu_loadvm_state_section_startfull(section_id, idstr,
+                                                      instance_id, version_id);
+            /* Find savevm section */
+            se = find_se(idstr, instance_id);
+            if (se == NULL) {
+                error_report("Unknown savevm section or instance '%s' %d",
+                             idstr, instance_id);
+                return -EINVAL;
+            }
+
+            /* Validate version */
+            if (version_id > se->version_id) {
+                error_report("savevm: unsupported version %d for '%s' v%d",
+                             version_id, idstr, se->version_id);
+                return -EINVAL;
+            }
+
+            /* Add entry */
+            le = g_malloc0(sizeof(*le));
+
+            le->se = se;
+            le->section_id = section_id;
+            le->version_id = version_id;
+            QLIST_INSERT_HEAD(&mis->loadvm_handlers, le, entry);
+
+            ret = vmstate_load(f, le->se, le->version_id);
+            if (ret < 0) {
+                error_report("error while loading state for instance 0x%x of"
+                             " device '%s'", instance_id, idstr);
+                return ret;
+            }
+            if (!check_section_footer(f, le)) {
+                return -EINVAL;
+            }
+            break;
+        case QEMU_VM_SECTION_PART:
+        case QEMU_VM_SECTION_END:
+            section_id = qemu_get_be32(f);
+
+            trace_qemu_loadvm_state_section_partend(section_id);
+            QLIST_FOREACH(le, &mis->loadvm_handlers, entry) {
+                if (le->section_id == section_id) {
+                    break;
+                }
+            }
+            if (le == NULL) {
+                error_report("Unknown savevm section %d", section_id);
+                return -EINVAL;
+            }
+
+            ret = vmstate_load(f, le->se, le->version_id);
+            if (ret < 0) {
+                error_report("error while loading state section id %d(%s)",
+                             section_id, le->se->idstr);
+                return ret;
+            }
+            if (!check_section_footer(f, le)) {
+                return -EINVAL;
+            }
+            break;
+        case QEMU_VM_COMMAND:
+            ret = loadvm_process_command(f);
+            trace_qemu_loadvm_state_section_command(ret);
+            if ((ret < 0) || (ret & LOADVM_QUIT)) {
+                return ret;
+            }
+            break;
+        default:
+            error_report("Unknown savevm section type %d", section_type);
+            return -EINVAL;
+        }
+    }
+
+    return 0;
+}
+
+int qemu_loadvm_state(QEMUFile *f)
+{
+    MigrationIncomingState *mis = migration_incoming_get_current();
+    Error *local_err = NULL;
+    unsigned int v;
+    int ret;
+
+    if (qemu_savevm_state_blocked(&local_err)) {
+        error_report_err(local_err);
+        return -EINVAL;
+    }
+
+    v = qemu_get_be32(f);
+    if (v != QEMU_VM_FILE_MAGIC) {
+        error_report("Not a migration stream");
+        return -EINVAL;
+    }
+
+    v = qemu_get_be32(f);
+    if (v == QEMU_VM_FILE_VERSION_COMPAT) {
+        error_report("SaveVM v2 format is obsolete and don't work anymore");
+        return -ENOTSUP;
+    }
+    if (v != QEMU_VM_FILE_VERSION) {
+        error_report("Unsupported migration stream version");
+        return -ENOTSUP;
+    }
+
+    if (!savevm_state.skip_configuration || enforce_config_section()) {
+        if (qemu_get_byte(f) != QEMU_VM_CONFIGURATION) {
+            error_report("Configuration section missing");
+            return -EINVAL;
+        }
+        ret = vmstate_load_state(f, &vmstate_configuration, &savevm_state, 0);
+
+        if (ret) {
+            return ret;
+        }
+    }
+
+    ret = qemu_loadvm_state_main(f, mis);
+    qemu_event_set(&mis->main_thread_load_event);
+
+    trace_qemu_loadvm_state_post_main(ret);
+
+    if (mis->have_listen_thread) {
+        /* Listen thread still going, can't clean up yet */
+        return ret;
+    }
+
+    if (ret == 0) {
+        ret = qemu_file_get_error(f);
+    }
+
+    /*
+     * Try to read in the VMDESC section as well, so that dumping tools that
+     * intercept our migration stream have the chance to see it.
+     */
+
+    /* We've got to be careful; if we don't read the data and just shut the fd
+     * then the sender can error if we close while it's still sending.
+     * We also mustn't read data that isn't there; some transports (RDMA)
+     * will stall waiting for that data when the source has already closed.
+     */
+    if (ret == 0 && should_send_vmdesc()) {
+        uint8_t *buf;
+        uint32_t size;
+        uint8_t  section_type = qemu_get_byte(f);
+
+        if (section_type != QEMU_VM_VMDESCRIPTION) {
+            error_report("Expected vmdescription section, but got %d",
+                         section_type);
+            /*
+             * It doesn't seem worth failing at this point since
+             * we apparently have an otherwise valid VM state
+             */
+        } else {
+            buf = g_malloc(0x1000);
+            size = qemu_get_be32(f);
+
+            while (size > 0) {
+                uint32_t read_chunk = MIN(size, 0x1000);
+                qemu_get_buffer(f, buf, read_chunk);
+                size -= read_chunk;
+            }
+            g_free(buf);
+        }
+    }
+
+    cpu_synchronize_all_post_init();
+
+    return ret;
+}
+
+void hmp_savevm(Monitor *mon, const QDict *qdict)
+{
+    BlockDriverState *bs, *bs1;
+    QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1;
+    int ret;
+    QEMUFile *f;
+    int saved_vm_running;
+    uint64_t vm_state_size;
+    qemu_timeval tv;
+    struct tm tm;
+    const char *name = qdict_get_try_str(qdict, "name");
+    Error *local_err = NULL;
+    AioContext *aio_context;
+
+    if (!bdrv_all_can_snapshot(&bs)) {
+        monitor_printf(mon, "Device '%s' is writable but does not "
+                       "support snapshots.\n", bdrv_get_device_name(bs));
+        return;
+    }
+
+    /* Delete old snapshots of the same name */
+    if (name && bdrv_all_delete_snapshot(name, &bs1, &local_err) < 0) {
+        monitor_printf(mon,
+                       "Error while deleting snapshot on device '%s': %s\n",
+                       bdrv_get_device_name(bs1), error_get_pretty(local_err));
+        error_free(local_err);
+        return;
+    }
+
+    bs = bdrv_all_find_vmstate_bs();
+    if (bs == NULL) {
+        monitor_printf(mon, "No block device can accept snapshots\n");
+        return;
+    }
+    aio_context = bdrv_get_aio_context(bs);
+
+    saved_vm_running = runstate_is_running();
+
+    ret = global_state_store();
+    if (ret) {
+        monitor_printf(mon, "Error saving global state\n");
+        return;
+    }
+    vm_stop(RUN_STATE_SAVE_VM);
+
+    aio_context_acquire(aio_context);
+
+    memset(sn, 0, sizeof(*sn));
+
+    /* fill auxiliary fields */
+    qemu_gettimeofday(&tv);
+    sn->date_sec = tv.tv_sec;
+    sn->date_nsec = tv.tv_usec * 1000;
+    sn->vm_clock_nsec = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+
+    if (name) {
+        ret = bdrv_snapshot_find(bs, old_sn, name);
+        if (ret >= 0) {
+            pstrcpy(sn->name, sizeof(sn->name), old_sn->name);
+            pstrcpy(sn->id_str, sizeof(sn->id_str), old_sn->id_str);
+        } else {
+            pstrcpy(sn->name, sizeof(sn->name), name);
+        }
+    } else {
+        /* cast below needed for OpenBSD where tv_sec is still 'long' */
+        localtime_r((const time_t *)&tv.tv_sec, &tm);
+        strftime(sn->name, sizeof(sn->name), "vm-%Y%m%d%H%M%S", &tm);
+    }
+
+    /* save the VM state */
+    f = qemu_fopen_bdrv(bs, 1);
+    if (!f) {
+        monitor_printf(mon, "Could not open VM state file\n");
+        goto the_end;
+    }
+    ret = qemu_savevm_state(f, &local_err);
+    vm_state_size = qemu_ftell(f);
+    qemu_fclose(f);
+    if (ret < 0) {
+        monitor_printf(mon, "%s\n", error_get_pretty(local_err));
+        error_free(local_err);
+        goto the_end;
+    }
+
+    ret = bdrv_all_create_snapshot(sn, bs, vm_state_size, &bs);
+    if (ret < 0) {
+        monitor_printf(mon, "Error while creating snapshot on '%s'\n",
+                       bdrv_get_device_name(bs));
+    }
+
+ the_end:
+    aio_context_release(aio_context);
+    if (saved_vm_running) {
+        vm_start();
+    }
+}
+
+void qmp_xen_save_devices_state(const char *filename, Error **errp)
+{
+    QEMUFile *f;
+    int saved_vm_running;
+    int ret;
+
+    saved_vm_running = runstate_is_running();
+    vm_stop(RUN_STATE_SAVE_VM);
+    global_state_store_running();
+
+    f = qemu_fopen(filename, "wb");
+    if (!f) {
+        error_setg_file_open(errp, errno, filename);
+        goto the_end;
+    }
+    ret = qemu_save_device_state(f);
+    qemu_fclose(f);
+    if (ret < 0) {
+        error_setg(errp, QERR_IO_ERROR);
+    }
+
+ the_end:
+    if (saved_vm_running) {
+        vm_start();
+    }
+}
+
+int load_vmstate(const char *name)
+{
+    BlockDriverState *bs, *bs_vm_state;
+    QEMUSnapshotInfo sn;
+    QEMUFile *f;
+    int ret;
+    AioContext *aio_context;
+
+    if (!bdrv_all_can_snapshot(&bs)) {
+        error_report("Device '%s' is writable but does not support snapshots.",
+                     bdrv_get_device_name(bs));
+        return -ENOTSUP;
+    }
+    ret = bdrv_all_find_snapshot(name, &bs);
+    if (ret < 0) {
+        error_report("Device '%s' does not have the requested snapshot '%s'",
+                     bdrv_get_device_name(bs), name);
+        return ret;
+    }
+
+    bs_vm_state = bdrv_all_find_vmstate_bs();
+    if (!bs_vm_state) {
+        error_report("No block device supports snapshots");
+        return -ENOTSUP;
+    }
+    aio_context = bdrv_get_aio_context(bs_vm_state);
+
+    /* Don't even try to load empty VM states */
+    aio_context_acquire(aio_context);
+    ret = bdrv_snapshot_find(bs_vm_state, &sn, name);
+    aio_context_release(aio_context);
+    if (ret < 0) {
+        return ret;
+    } else if (sn.vm_state_size == 0) {
+        error_report("This is a disk-only snapshot. Revert to it offline "
+            "using qemu-img.");
+        return -EINVAL;
+    }
+
+    /* Flush all IO requests so they don't interfere with the new state.  */
+    bdrv_drain_all();
+
+    ret = bdrv_all_goto_snapshot(name, &bs);
+    if (ret < 0) {
+        error_report("Error %d while activating snapshot '%s' on '%s'",
+                     ret, name, bdrv_get_device_name(bs));
+        return ret;
+    }
+
+    /* restore the VM state */
+    f = qemu_fopen_bdrv(bs_vm_state, 0);
+    if (!f) {
+        error_report("Could not open VM state file");
+        return -EINVAL;
+    }
+
+    qemu_system_reset(VMRESET_SILENT);
+    migration_incoming_state_new(f);
+
+    aio_context_acquire(aio_context);
+    ret = qemu_loadvm_state(f);
+    qemu_fclose(f);
+    aio_context_release(aio_context);
+
+    migration_incoming_state_destroy();
+    if (ret < 0) {
+        error_report("Error %d while loading VM state", ret);
+        return ret;
+    }
+
+    return 0;
+}
+
+void hmp_delvm(Monitor *mon, const QDict *qdict)
+{
+    BlockDriverState *bs;
+    Error *err;
+    const char *name = qdict_get_str(qdict, "name");
+
+    if (bdrv_all_delete_snapshot(name, &bs, &err) < 0) {
+        monitor_printf(mon,
+                       "Error while deleting snapshot on device '%s': %s\n",
+                       bdrv_get_device_name(bs), error_get_pretty(err));
+        error_free(err);
+    }
+}
+
+void hmp_info_snapshots(Monitor *mon, const QDict *qdict)
+{
+    BlockDriverState *bs, *bs1;
+    QEMUSnapshotInfo *sn_tab, *sn;
+    int nb_sns, i;
+    int total;
+    int *available_snapshots;
+    AioContext *aio_context;
+
+    bs = bdrv_all_find_vmstate_bs();
+    if (!bs) {
+        monitor_printf(mon, "No available block device supports snapshots\n");
+        return;
+    }
+    aio_context = bdrv_get_aio_context(bs);
+
+    aio_context_acquire(aio_context);
+    nb_sns = bdrv_snapshot_list(bs, &sn_tab);
+    aio_context_release(aio_context);
+
+    if (nb_sns < 0) {
+        monitor_printf(mon, "bdrv_snapshot_list: error %d\n", nb_sns);
+        return;
+    }
+
+    if (nb_sns == 0) {
+        monitor_printf(mon, "There is no snapshot available.\n");
+        return;
+    }
+
+    available_snapshots = g_new0(int, nb_sns);
+    total = 0;
+    for (i = 0; i < nb_sns; i++) {
+        if (bdrv_all_find_snapshot(sn_tab[i].id_str, &bs1) == 0) {
+            available_snapshots[total] = i;
+            total++;
+        }
+    }
+
+    if (total > 0) {
+        bdrv_snapshot_dump((fprintf_function)monitor_printf, mon, NULL);
+        monitor_printf(mon, "\n");
+        for (i = 0; i < total; i++) {
+            sn = &sn_tab[available_snapshots[i]];
+            bdrv_snapshot_dump((fprintf_function)monitor_printf, mon, sn);
+            monitor_printf(mon, "\n");
+        }
+    } else {
+        monitor_printf(mon, "There is no suitable snapshot available\n");
+    }
+
+    g_free(sn_tab);
+    g_free(available_snapshots);
+
+}
+
+void vmstate_register_ram(MemoryRegion *mr, DeviceState *dev)
+{
+    qemu_ram_set_idstr(memory_region_get_ram_addr(mr) & TARGET_PAGE_MASK,
+                       memory_region_name(mr), dev);
+}
+
+void vmstate_unregister_ram(MemoryRegion *mr, DeviceState *dev)
+{
+    qemu_ram_unset_idstr(memory_region_get_ram_addr(mr) & TARGET_PAGE_MASK);
+}
+
+void vmstate_register_ram_global(MemoryRegion *mr)
+{
+    vmstate_register_ram(mr, NULL);
+}