]> git.proxmox.com Git - qemu.git/blobdiff - savevm.c
slirp: Strictly associate DHCP/BOOTP and TFTP with virtual host
[qemu.git] / savevm.c
index 55a2763f0f7c3b603853525aaeccb88b2e8ec2d0..8139bc7e297db9604bfc7a607025a435b6aec75f 100644 (file)
--- a/savevm.c
+++ b/savevm.c
@@ -23,7 +23,6 @@
  */
 #include <unistd.h>
 #include <fcntl.h>
-#include <signal.h>
 #include <time.h>
 #include <errno.h>
 #include <sys/time.h>
 
 #include "qemu-common.h"
 #include "hw/hw.h"
+#include "hw/qdev.h"
 #include "net.h"
 #include "monitor.h"
 #include "sysemu.h"
 #include "qemu-timer.h"
 #include "qemu-char.h"
-#include "block.h"
 #include "audio/audio.h"
 #include "migration.h"
 #include "qemu_socket.h"
 #include "qemu-queue.h"
-
-/* point to the block driver where the snapshots are managed */
-static BlockDriverState *bs_snapshots;
+#include "cpus.h"
 
 #define SELF_ANNOUNCE_ROUNDS 5
 
 #ifndef ETH_P_RARP
-#define ETH_P_RARP 0x0835
+#define ETH_P_RARP 0x8035
 #endif
 #define ARP_HTYPE_ETH 0x0001
 #define ARP_PTYPE_IP 0x0800
@@ -140,7 +137,7 @@ static void qemu_announce_self_once(void *opaque)
 
     if (--count) {
         /* delay 50ms, 150ms, 250ms, ... */
-        qemu_mod_timer(timer, qemu_get_clock(rt_clock) +
+        qemu_mod_timer(timer, qemu_get_clock_ms(rt_clock) +
                        50 + (SELF_ANNOUNCE_ROUNDS - count - 1) * 100);
     } else {
            qemu_del_timer(timer);
@@ -151,7 +148,7 @@ static void qemu_announce_self_once(void *opaque)
 void qemu_announce_self(void)
 {
        static QEMUTimer *timer;
-       timer = qemu_new_timer(rt_clock, qemu_announce_self_once, &timer);
+       timer = qemu_new_timer_ms(rt_clock, qemu_announce_self_once, &timer);
        qemu_announce_self_once(&timer);
 }
 
@@ -235,9 +232,10 @@ static int stdio_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
 static int stdio_pclose(void *opaque)
 {
     QEMUFileStdio *s = opaque;
-    pclose(s->stdio_file);
+    int ret;
+    ret = pclose(s->stdio_file);
     qemu_free(s);
-    return 0;
+    return ret;
 }
 
 static int stdio_fclose(void *opaque)
@@ -339,8 +337,7 @@ static int file_put_buffer(void *opaque, const uint8_t *buf,
 {
     QEMUFileStdio *s = opaque;
     fseek(s->stdio_file, pos, SEEK_SET);
-    fwrite(buf, 1, size, s->stdio_file);
-    return size;
+    return fwrite(buf, 1, size, s->stdio_file);
 }
 
 static int file_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
@@ -357,7 +354,7 @@ QEMUFile *qemu_fopen(const char *filename, const char *mode)
     if (mode == NULL ||
        (mode[0] != 'r' && mode[0] != 'w') ||
        mode[1] != 'b' || mode[2] != 0) {
-        fprintf(stderr, "qemu_fdopen: Argument validity check failed\n");
+        fprintf(stderr, "qemu_fopen: Argument validity check failed\n");
         return NULL;
     }
 
@@ -553,6 +550,19 @@ int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size1)
     return size1 - size;
 }
 
+static int qemu_peek_byte(QEMUFile *f)
+{
+    if (f->is_write)
+        abort();
+
+    if (f->buf_index >= f->buf_size) {
+        qemu_fill_buffer(f);
+        if (f->buf_index >= f->buf_size)
+            return 0;
+    }
+    return f->buf[f->buf_index];
+}
+
 int qemu_get_byte(QEMUFile *f)
 {
     if (f->is_write)
@@ -600,7 +610,7 @@ int qemu_file_rate_limit(QEMUFile *f)
     return 0;
 }
 
-size_t qemu_file_get_rate_limit(QEMUFile *f)
+int64_t qemu_file_get_rate_limit(QEMUFile *f)
 {
     if (f->get_rate_limit)
         return f->get_rate_limit(f->opaque);
@@ -608,7 +618,7 @@ size_t qemu_file_get_rate_limit(QEMUFile *f)
     return 0;
 }
 
-size_t qemu_file_set_rate_limit(QEMUFile *f, size_t new_rate)
+int64_t qemu_file_set_rate_limit(QEMUFile *f, int64_t new_rate)
 {
     /* any failed or completed migration keeps its state to allow probing of
      * migration data, but has no associated file anymore */
@@ -664,6 +674,27 @@ uint64_t qemu_get_be64(QEMUFile *f)
     return v;
 }
 
+/* bool */
+
+static int get_bool(QEMUFile *f, void *pv, size_t size)
+{
+    bool *v = pv;
+    *v = qemu_get_byte(f);
+    return 0;
+}
+
+static void put_bool(QEMUFile *f, void *pv, size_t size)
+{
+    bool *v = pv;
+    qemu_put_byte(f, *v);
+}
+
+const VMStateInfo vmstate_info_bool = {
+    .name = "bool",
+    .get  = get_bool,
+    .put  = put_bool,
+};
+
 /* 8 bit int */
 
 static int get_int8(QEMUFile *f, void *pv, size_t size)
@@ -851,6 +882,27 @@ const VMStateInfo vmstate_info_uint32 = {
     .put  = put_uint32,
 };
 
+/* 32 bit uint. See that the received value is the same than the one
+   in the field */
+
+static int get_uint32_equal(QEMUFile *f, void *pv, size_t size)
+{
+    uint32_t *v = pv;
+    uint32_t v2;
+    qemu_get_be32s(f, &v2);
+
+    if (*v == v2) {
+        return 0;
+    }
+    return -EINVAL;
+}
+
+const VMStateInfo vmstate_info_uint32_equal = {
+    .name = "uint32 equal",
+    .get  = get_uint32_equal,
+    .put  = put_uint32,
+};
+
 /* 64 bit unsigned int */
 
 static int get_uint64(QEMUFile *f, void *pv, size_t size)
@@ -955,7 +1007,7 @@ const VMStateInfo vmstate_info_buffer = {
 };
 
 /* unused buffers: space that was used for some fields that are
-   not usefull anymore */
+   not useful anymore */
 
 static int get_unused_buffer(QEMUFile *f, void *pv, size_t size)
 {
@@ -988,10 +1040,16 @@ const VMStateInfo vmstate_info_unused_buffer = {
     .put  = put_unused_buffer,
 };
 
+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;
     SaveSetParamsHandler *set_params;
@@ -1000,6 +1058,8 @@ typedef struct SaveStateEntry {
     LoadStateHandler *load_state;
     const VMStateDescription *vmsd;
     void *opaque;
+    CompatEntry *compat;
+    int no_migrate;
 } SaveStateEntry;
 
 
@@ -1021,11 +1081,29 @@ static int calculate_new_instance_id(const char *idstr)
     return instance_id;
 }
 
+static int calculate_compat_instance_id(const char *idstr)
+{
+    SaveStateEntry *se;
+    int instance_id = 0;
+
+    QTAILQ_FOREACH(se, &savevm_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(const char *idstr,
+int register_savevm_live(DeviceState *dev,
+                         const char *idstr,
                          int instance_id,
                          int version_id,
                          SaveSetParamsHandler *set_params,
@@ -1037,7 +1115,6 @@ int register_savevm_live(const char *idstr,
     SaveStateEntry *se;
 
     se = qemu_mallocz(sizeof(SaveStateEntry));
-    pstrcpy(se->idstr, sizeof(se->idstr), idstr);
     se->version_id = version_id;
     se->section_id = global_section_id++;
     se->set_params = set_params;
@@ -1046,47 +1123,109 @@ int register_savevm_live(const char *idstr,
     se->load_state = load_state;
     se->opaque = opaque;
     se->vmsd = NULL;
+    se->no_migrate = 0;
+
+    if (dev && dev->parent_bus && dev->parent_bus->info->get_dev_path) {
+        char *id = dev->parent_bus->info->get_dev_path(dev);
+        if (id) {
+            pstrcpy(se->idstr, sizeof(se->idstr), id);
+            pstrcat(se->idstr, sizeof(se->idstr), "/");
+            qemu_free(id);
+
+            se->compat = qemu_mallocz(sizeof(CompatEntry));
+            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(idstr);
+        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_handlers, se, entry);
     return 0;
 }
 
-int register_savevm(const char *idstr,
+int register_savevm(DeviceState *dev,
+                    const char *idstr,
                     int instance_id,
                     int version_id,
                     SaveStateHandler *save_state,
                     LoadStateHandler *load_state,
                     void *opaque)
 {
-    return register_savevm_live(idstr, instance_id, version_id,
+    return register_savevm_live(dev, idstr, instance_id, version_id,
                                 NULL, NULL, save_state, load_state, opaque);
 }
 
-void unregister_savevm(const char *idstr, void *opaque)
+void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque)
 {
     SaveStateEntry *se, *new_se;
+    char id[256] = "";
+
+    if (dev && dev->parent_bus && dev->parent_bus->info->get_dev_path) {
+        char *path = dev->parent_bus->info->get_dev_path(dev);
+        if (path) {
+            pstrcpy(id, sizeof(id), path);
+            pstrcat(id, sizeof(id), "/");
+            qemu_free(path);
+        }
+    }
+    pstrcat(id, sizeof(id), idstr);
 
     QTAILQ_FOREACH_SAFE(se, &savevm_handlers, entry, new_se) {
-        if (strcmp(se->idstr, idstr) == 0 && se->opaque == opaque) {
+        if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) {
             QTAILQ_REMOVE(&savevm_handlers, se, entry);
+            if (se->compat) {
+                qemu_free(se->compat);
+            }
             qemu_free(se);
         }
     }
 }
 
-int vmstate_register(int instance_id, const VMStateDescription *vmsd,
-                     void *opaque)
+/* mark a device as not to be migrated, that is the device should be
+   unplugged before migration */
+void register_device_unmigratable(DeviceState *dev, const char *idstr,
+                                                            void *opaque)
 {
     SaveStateEntry *se;
+    char id[256] = "";
+
+    if (dev && dev->parent_bus && dev->parent_bus->info->get_dev_path) {
+        char *path = dev->parent_bus->info->get_dev_path(dev);
+        if (path) {
+            pstrcpy(id, sizeof(id), path);
+            pstrcat(id, sizeof(id), "/");
+            qemu_free(path);
+        }
+    }
+    pstrcat(id, sizeof(id), idstr);
+
+    QTAILQ_FOREACH(se, &savevm_handlers, entry) {
+        if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) {
+            se->no_migrate = 1;
+        }
+    }
+}
+
+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 = qemu_mallocz(sizeof(SaveStateEntry));
-    pstrcpy(se->idstr, sizeof(se->idstr), vmsd->name);
     se->version_id = vmsd->version_id;
     se->section_id = global_section_id++;
     se->save_live_state = NULL;
@@ -1094,33 +1233,68 @@ int vmstate_register(int instance_id, const VMStateDescription *vmsd,
     se->load_state = NULL;
     se->opaque = opaque;
     se->vmsd = vmsd;
+    se->alias_id = alias_id;
+
+    if (dev && dev->parent_bus && dev->parent_bus->info->get_dev_path) {
+        char *id = dev->parent_bus->info->get_dev_path(dev);
+        if (id) {
+            pstrcpy(se->idstr, sizeof(se->idstr), id);
+            pstrcat(se->idstr, sizeof(se->idstr), "/");
+            qemu_free(id);
+
+            se->compat = qemu_mallocz(sizeof(CompatEntry));
+            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(vmsd->name);
+        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_handlers, se, entry);
     return 0;
 }
 
-void vmstate_unregister(const VMStateDescription *vmsd, void *opaque)
+int vmstate_register(DeviceState *dev, int instance_id,
+                     const VMStateDescription *vmsd, void *opaque)
+{
+    return vmstate_register_with_alias_id(dev, instance_id, vmsd,
+                                          opaque, -1, 0);
+}
+
+void vmstate_unregister(DeviceState *dev, const VMStateDescription *vmsd,
+                        void *opaque)
 {
     SaveStateEntry *se, *new_se;
 
     QTAILQ_FOREACH_SAFE(se, &savevm_handlers, entry, new_se) {
         if (se->vmsd == vmsd && se->opaque == opaque) {
             QTAILQ_REMOVE(&savevm_handlers, se, entry);
+            if (se->compat) {
+                qemu_free(se->compat);
+            }
             qemu_free(se);
         }
     }
 }
 
+static void vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
+                                    void *opaque);
+static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
+                                   void *opaque);
+
 int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
                        void *opaque, int version_id)
 {
     VMStateField *field = vmsd->fields;
+    int ret;
 
     if (version_id > vmsd->version_id) {
         return -EINVAL;
@@ -1142,20 +1316,31 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
             (!field->field_exists &&
              field->version_id <= version_id)) {
             void *base_addr = opaque + field->offset;
-            int ret, i, n_elems = 1;
+            int i, n_elems = 1;
+            int size = field->size;
 
+            if (field->flags & VMS_VBUFFER) {
+                size = *(int32_t *)(opaque+field->size_offset);
+                if (field->flags & VMS_MULTIPLY) {
+                    size *= field->size;
+                }
+            }
             if (field->flags & VMS_ARRAY) {
                 n_elems = field->num;
             } else if (field->flags & VMS_VARRAY_INT32) {
                 n_elems = *(int32_t *)(opaque+field->num_offset);
+            } else if (field->flags & VMS_VARRAY_UINT32) {
+                n_elems = *(uint32_t *)(opaque+field->num_offset);
             } else if (field->flags & VMS_VARRAY_UINT16) {
                 n_elems = *(uint16_t *)(opaque+field->num_offset);
+            } else if (field->flags & VMS_VARRAY_UINT8) {
+                n_elems = *(uint8_t *)(opaque+field->num_offset);
             }
             if (field->flags & VMS_POINTER) {
-                base_addr = *(void **)base_addr;
+                base_addr = *(void **)base_addr + field->start;
             }
             for (i = 0; i < n_elems; i++) {
-                void *addr = base_addr + field->size * i;
+                void *addr = base_addr + size * i;
 
                 if (field->flags & VMS_ARRAY_OF_POINTER) {
                     addr = *(void **)addr;
@@ -1163,7 +1348,7 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
                 if (field->flags & VMS_STRUCT) {
                     ret = vmstate_load_state(f, field->vmsd, addr, field->vmsd->version_id);
                 } else {
-                    ret = field->info->get(f, addr, field->size);
+                    ret = field->info->get(f, addr, size);
 
                 }
                 if (ret < 0) {
@@ -1173,6 +1358,10 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
         }
         field++;
     }
+    ret = vmstate_subsection_load(f, vmsd, opaque);
+    if (ret != 0) {
+        return ret;
+    }
     if (vmsd->post_load) {
         return vmsd->post_load(opaque, version_id);
     }
@@ -1192,32 +1381,42 @@ void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
             field->field_exists(opaque, vmsd->version_id)) {
             void *base_addr = opaque + field->offset;
             int i, n_elems = 1;
+            int size = field->size;
 
+            if (field->flags & VMS_VBUFFER) {
+                size = *(int32_t *)(opaque+field->size_offset);
+                if (field->flags & VMS_MULTIPLY) {
+                    size *= field->size;
+                }
+            }
             if (field->flags & VMS_ARRAY) {
                 n_elems = field->num;
             } else if (field->flags & VMS_VARRAY_INT32) {
                 n_elems = *(int32_t *)(opaque+field->num_offset);
             } else if (field->flags & VMS_VARRAY_UINT16) {
                 n_elems = *(uint16_t *)(opaque+field->num_offset);
+            } else if (field->flags & VMS_VARRAY_UINT8) {
+                n_elems = *(uint8_t *)(opaque+field->num_offset);
             }
             if (field->flags & VMS_POINTER) {
-                base_addr = *(void **)base_addr;
+                base_addr = *(void **)base_addr + field->start;
             }
             for (i = 0; i < n_elems; i++) {
-                void *addr = base_addr + field->size * i;
+                void *addr = base_addr + size * i;
 
+                if (field->flags & VMS_ARRAY_OF_POINTER) {
+                    addr = *(void **)addr;
+                }
                 if (field->flags & VMS_STRUCT) {
                     vmstate_save_state(f, field->vmsd, addr);
                 } else {
-                    field->info->put(f, addr, field->size);
+                    field->info->put(f, addr, size);
                 }
             }
         }
         field++;
     }
-    if (vmsd->post_save) {
-        vmsd->post_save(opaque);
-    }
+    vmstate_subsection_save(f, vmsd, opaque);
 }
 
 static int vmstate_load(QEMUFile *f, SaveStateEntry *se, int version_id)
@@ -1246,8 +1445,24 @@ static void vmstate_save(QEMUFile *f, SaveStateEntry *se)
 #define QEMU_VM_SECTION_PART         0x02
 #define QEMU_VM_SECTION_END          0x03
 #define QEMU_VM_SECTION_FULL         0x04
+#define QEMU_VM_SUBSECTION           0x05
+
+bool qemu_savevm_state_blocked(Monitor *mon)
+{
+    SaveStateEntry *se;
+
+    QTAILQ_FOREACH(se, &savevm_handlers, entry) {
+        if (se->no_migrate) {
+            monitor_printf(mon, "state blocked by non-migratable device '%s'\n",
+                           se->idstr);
+            return true;
+        }
+    }
+    return false;
+}
 
-int qemu_savevm_state_begin(QEMUFile *f, int blk_enable, int shared)
+int qemu_savevm_state_begin(Monitor *mon, QEMUFile *f, int blk_enable,
+                            int shared)
 {
     SaveStateEntry *se;
 
@@ -1279,16 +1494,18 @@ int qemu_savevm_state_begin(QEMUFile *f, int blk_enable, int shared)
         qemu_put_be32(f, se->instance_id);
         qemu_put_be32(f, se->version_id);
 
-        se->save_live_state(f, QEMU_VM_SECTION_START, se->opaque);
+        se->save_live_state(mon, f, QEMU_VM_SECTION_START, se->opaque);
     }
 
-    if (qemu_file_has_error(f))
+    if (qemu_file_has_error(f)) {
+        qemu_savevm_state_cancel(mon, f);
         return -EIO;
+    }
 
     return 0;
 }
 
-int qemu_savevm_state_iterate(QEMUFile *f)
+int qemu_savevm_state_iterate(Monitor *mon, QEMUFile *f)
 {
     SaveStateEntry *se;
     int ret = 1;
@@ -1301,22 +1518,33 @@ int qemu_savevm_state_iterate(QEMUFile *f)
         qemu_put_byte(f, QEMU_VM_SECTION_PART);
         qemu_put_be32(f, se->section_id);
 
-        ret &= !!se->save_live_state(f, QEMU_VM_SECTION_PART, se->opaque);
+        ret = se->save_live_state(mon, f, QEMU_VM_SECTION_PART, se->opaque);
+        if (!ret) {
+            /* 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;
+        }
     }
 
     if (ret)
         return 1;
 
-    if (qemu_file_has_error(f))
+    if (qemu_file_has_error(f)) {
+        qemu_savevm_state_cancel(mon, f);
         return -EIO;
+    }
 
     return 0;
 }
 
-int qemu_savevm_state_complete(QEMUFile *f)
+int qemu_savevm_state_complete(Monitor *mon, QEMUFile *f)
 {
     SaveStateEntry *se;
 
+    cpu_synchronize_all_states();
+
     QTAILQ_FOREACH(se, &savevm_handlers, entry) {
         if (se->save_live_state == NULL)
             continue;
@@ -1325,7 +1553,7 @@ int qemu_savevm_state_complete(QEMUFile *f)
         qemu_put_byte(f, QEMU_VM_SECTION_END);
         qemu_put_be32(f, se->section_id);
 
-        se->save_live_state(f, QEMU_VM_SECTION_END, se->opaque);
+        se->save_live_state(mon, f, QEMU_VM_SECTION_END, se->opaque);
     }
 
     QTAILQ_FOREACH(se, &savevm_handlers, entry) {
@@ -1357,27 +1585,41 @@ int qemu_savevm_state_complete(QEMUFile *f)
     return 0;
 }
 
-int qemu_savevm_state(QEMUFile *f)
+void qemu_savevm_state_cancel(Monitor *mon, QEMUFile *f)
+{
+    SaveStateEntry *se;
+
+    QTAILQ_FOREACH(se, &savevm_handlers, entry) {
+        if (se->save_live_state) {
+            se->save_live_state(mon, f, -1, se->opaque);
+        }
+    }
+}
+
+static int qemu_savevm_state(Monitor *mon, QEMUFile *f)
 {
     int saved_vm_running;
     int ret;
 
     saved_vm_running = vm_running;
-    vm_stop(0);
+    vm_stop(VMSTOP_SAVEVM);
 
-    bdrv_flush_all();
+    if (qemu_savevm_state_blocked(mon)) {
+        ret = -EINVAL;
+        goto out;
+    }
 
-    ret = qemu_savevm_state_begin(f, 0, 0);
+    ret = qemu_savevm_state_begin(mon, f, 0, 0);
     if (ret < 0)
         goto out;
 
     do {
-        ret = qemu_savevm_state_iterate(f);
+        ret = qemu_savevm_state_iterate(mon, f);
         if (ret < 0)
             goto out;
     } while (ret == 0);
 
-    ret = qemu_savevm_state_complete(f);
+    ret = qemu_savevm_state_complete(mon, f);
 
 out:
     if (qemu_file_has_error(f))
@@ -1395,12 +1637,87 @@ static SaveStateEntry *find_se(const char *idstr, int instance_id)
 
     QTAILQ_FOREACH(se, &savevm_handlers, entry) {
         if (!strcmp(se->idstr, idstr) &&
-            instance_id == se->instance_id)
+            (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;
 }
 
+static const VMStateDescription *vmstate_get_subsection(const VMStateSubsection *sub, char *idstr)
+{
+    while(sub && sub->needed) {
+        if (strcmp(idstr, sub->vmsd->name) == 0) {
+            return sub->vmsd;
+        }
+        sub++;
+    }
+    return NULL;
+}
+
+static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
+                                   void *opaque)
+{
+    const VMStateSubsection *sub = vmsd->subsections;
+
+    if (!sub || !sub->needed) {
+        return 0;
+    }
+
+    while (qemu_peek_byte(f) == QEMU_VM_SUBSECTION) {
+        char idstr[256];
+        int ret;
+        uint8_t version_id, len;
+        const VMStateDescription *sub_vmsd;
+
+        qemu_get_byte(f); /* subsection */
+        len = qemu_get_byte(f);
+        qemu_get_buffer(f, (uint8_t *)idstr, len);
+        idstr[len] = 0;
+        version_id = qemu_get_be32(f);
+
+        sub_vmsd = vmstate_get_subsection(sub, idstr);
+        if (sub_vmsd == NULL) {
+            return -ENOENT;
+        }
+        assert(!sub_vmsd->subsections);
+        ret = vmstate_load_state(f, sub_vmsd, opaque, version_id);
+        if (ret) {
+            return ret;
+        }
+    }
+    return 0;
+}
+
+static void vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
+                                    void *opaque)
+{
+    const VMStateSubsection *sub = vmsd->subsections;
+
+    while (sub && sub->needed) {
+        if (sub->needed(opaque)) {
+            const VMStateDescription *vmsd = sub->vmsd;
+            uint8_t len;
+
+            qemu_put_byte(f, QEMU_VM_SUBSECTION);
+            len = strlen(vmsd->name);
+            qemu_put_byte(f, len);
+            qemu_put_buffer(f, (uint8_t *)vmsd->name, len);
+            qemu_put_be32(f, vmsd->version_id);
+            assert(!vmsd->subsections);
+            vmstate_save_state(f, vmsd, opaque);
+        }
+        sub++;
+    }
+}
+
 typedef struct LoadStateEntry {
     QLIST_ENTRY(LoadStateEntry) entry;
     SaveStateEntry *se;
@@ -1417,6 +1734,10 @@ int qemu_loadvm_state(QEMUFile *f)
     unsigned int v;
     int ret;
 
+    if (qemu_savevm_state_blocked(default_mon)) {
+        return -EINVAL;
+    }
+
     v = qemu_get_be32(f);
     if (v != QEMU_VM_FILE_MAGIC)
         return -EINVAL;
@@ -1506,6 +1827,8 @@ int qemu_loadvm_state(QEMUFile *f)
         }
     }
 
+    cpu_synchronize_all_post_init();
+
     ret = 0;
 
 out:
@@ -1520,40 +1843,6 @@ out:
     return ret;
 }
 
-/* device can contain snapshots */
-static int bdrv_can_snapshot(BlockDriverState *bs)
-{
-    return (bs &&
-            !bdrv_is_removable(bs) &&
-            !bdrv_is_read_only(bs));
-}
-
-/* device must be snapshots in order to have a reliable snapshot */
-static int bdrv_has_snapshot(BlockDriverState *bs)
-{
-    return (bs &&
-            !bdrv_is_removable(bs) &&
-            !bdrv_is_read_only(bs));
-}
-
-static BlockDriverState *get_bs_snapshots(void)
-{
-    BlockDriverState *bs;
-    DriveInfo *dinfo;
-
-    if (bs_snapshots)
-        return bs_snapshots;
-    QTAILQ_FOREACH(dinfo, &drives, next) {
-        bs = dinfo->bdrv;
-        if (bdrv_can_snapshot(bs))
-            goto ok;
-    }
-    return NULL;
- ok:
-    bs_snapshots = bs;
-    return bs;
-}
-
 static int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info,
                               const char *name)
 {
@@ -1582,12 +1871,11 @@ static int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info,
 static int del_existing_snapshots(Monitor *mon, const char *name)
 {
     BlockDriverState *bs;
-    DriveInfo *dinfo;
     QEMUSnapshotInfo sn1, *snapshot = &sn1;
     int ret;
 
-    QTAILQ_FOREACH(dinfo, &drives, next) {
-        bs = dinfo->bdrv;
+    bs = NULL;
+    while ((bs = bdrv_next(bs))) {
         if (bdrv_can_snapshot(bs) &&
             bdrv_snapshot_find(bs, snapshot, name) >= 0)
         {
@@ -1606,7 +1894,6 @@ static int del_existing_snapshots(Monitor *mon, const char *name)
 
 void do_savevm(Monitor *mon, const QDict *qdict)
 {
-    DriveInfo *dinfo;
     BlockDriverState *bs, *bs1;
     QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1;
     int ret;
@@ -1615,33 +1902,38 @@ void do_savevm(Monitor *mon, const QDict *qdict)
     uint32_t vm_state_size;
 #ifdef _WIN32
     struct _timeb tb;
+    struct tm *ptm;
 #else
     struct timeval tv;
+    struct tm tm;
 #endif
     const char *name = qdict_get_try_str(qdict, "name");
 
-    bs = get_bs_snapshots();
+    /* Verify if there is a device that doesn't support snapshots and is writable */
+    bs = NULL;
+    while ((bs = bdrv_next(bs))) {
+
+        if (bdrv_is_removable(bs) || bdrv_is_read_only(bs)) {
+            continue;
+        }
+
+        if (!bdrv_can_snapshot(bs)) {
+            monitor_printf(mon, "Device '%s' is writable but does not support snapshots.\n",
+                               bdrv_get_device_name(bs));
+            return;
+        }
+    }
+
+    bs = bdrv_snapshots();
     if (!bs) {
         monitor_printf(mon, "No block device can accept snapshots\n");
         return;
     }
 
-    /* ??? Should this occur after vm_stop?  */
-    qemu_aio_flush();
-
     saved_vm_running = vm_running;
-    vm_stop(0);
+    vm_stop(VMSTOP_SAVEVM);
 
     memset(sn, 0, sizeof(*sn));
-    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);
-        }
-    }
 
     /* fill auxiliary fields */
 #ifdef _WIN32
@@ -1653,10 +1945,29 @@ void do_savevm(Monitor *mon, const QDict *qdict)
     sn->date_sec = tv.tv_sec;
     sn->date_nsec = tv.tv_usec * 1000;
 #endif
-    sn->vm_clock_nsec = qemu_get_clock(vm_clock);
+    sn->vm_clock_nsec = qemu_get_clock_ns(vm_clock);
+
+    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 {
+#ifdef _WIN32
+        ptm = localtime(&tb.time);
+        strftime(sn->name, sizeof(sn->name), "vm-%Y%m%d%H%M%S", ptm);
+#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);
+#endif
+    }
 
     /* Delete old snapshots of the same name */
-    if (del_existing_snapshots(mon, name) < 0) {
+    if (name && del_existing_snapshots(mon, name) < 0) {
         goto the_end;
     }
 
@@ -1666,7 +1977,7 @@ void do_savevm(Monitor *mon, const QDict *qdict)
         monitor_printf(mon, "Could not open VM state file\n");
         goto the_end;
     }
-    ret = qemu_savevm_state(f);
+    ret = qemu_savevm_state(mon, f);
     vm_state_size = qemu_ftell(f);
     qemu_fclose(f);
     if (ret < 0) {
@@ -1676,9 +1987,9 @@ void do_savevm(Monitor *mon, const QDict *qdict)
 
     /* create the snapshots */
 
-    QTAILQ_FOREACH(dinfo, &drives, next) {
-        bs1 = dinfo->bdrv;
-        if (bdrv_has_snapshot(bs1)) {
+    bs1 = NULL;
+    while ((bs1 = bdrv_next(bs1))) {
+        if (bdrv_can_snapshot(bs1)) {
             /* Write VM state size only to the image that contains the state */
             sn->vm_state_size = (bs == bs1 ? vm_state_size : 0);
             ret = bdrv_snapshot_create(bs1, sn);
@@ -1694,89 +2005,101 @@ void do_savevm(Monitor *mon, const QDict *qdict)
         vm_start();
 }
 
-int load_vmstate(Monitor *mon, const char *name)
+int load_vmstate(const char *name)
 {
-    DriveInfo *dinfo;
-    BlockDriverState *bs, *bs1;
+    BlockDriverState *bs, *bs_vm_state;
     QEMUSnapshotInfo sn;
     QEMUFile *f;
     int ret;
 
-    bs = get_bs_snapshots();
-    if (!bs) {
-        monitor_printf(mon, "No block device supports snapshots\n");
+    bs_vm_state = bdrv_snapshots();
+    if (!bs_vm_state) {
+        error_report("No block device supports snapshots");
+        return -ENOTSUP;
+    }
+
+    /* Don't even try to load empty VM states */
+    ret = bdrv_snapshot_find(bs_vm_state, &sn, name);
+    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;
     }
 
+    /* Verify if there is any device that doesn't support snapshots and is
+    writable and check if the requested snapshot is available too. */
+    bs = NULL;
+    while ((bs = bdrv_next(bs))) {
+
+        if (bdrv_is_removable(bs) || bdrv_is_read_only(bs)) {
+            continue;
+        }
+
+        if (!bdrv_can_snapshot(bs)) {
+            error_report("Device '%s' is writable but does not support snapshots.",
+                               bdrv_get_device_name(bs));
+            return -ENOTSUP;
+        }
+
+        ret = bdrv_snapshot_find(bs, &sn, name);
+        if (ret < 0) {
+            error_report("Device '%s' does not have the requested snapshot '%s'",
+                           bdrv_get_device_name(bs), name);
+            return ret;
+        }
+    }
+
     /* Flush all IO requests so they don't interfere with the new state.  */
     qemu_aio_flush();
 
-    QTAILQ_FOREACH(dinfo, &drives, next) {
-        bs1 = dinfo->bdrv;
-        if (bdrv_has_snapshot(bs1)) {
-            ret = bdrv_snapshot_goto(bs1, name);
+    bs = NULL;
+    while ((bs = bdrv_next(bs))) {
+        if (bdrv_can_snapshot(bs)) {
+            ret = bdrv_snapshot_goto(bs, name);
             if (ret < 0) {
-                if (bs != bs1)
-                    monitor_printf(mon, "Warning: ");
-                switch(ret) {
-                case -ENOTSUP:
-                    monitor_printf(mon,
-                                   "Snapshots not supported on device '%s'\n",
-                                   bdrv_get_device_name(bs1));
-                    break;
-                case -ENOENT:
-                    monitor_printf(mon, "Could not find snapshot '%s' on "
-                                   "device '%s'\n",
-                                   name, bdrv_get_device_name(bs1));
-                    break;
-                default:
-                    monitor_printf(mon, "Error %d while activating snapshot on"
-                                   " '%s'\n", ret, bdrv_get_device_name(bs1));
-                    break;
-                }
-                /* fatal on snapshot block device */
-                if (bs == bs1)
-                    return 0;
+                error_report("Error %d while activating snapshot '%s' on '%s'",
+                             ret, name, bdrv_get_device_name(bs));
+                return ret;
             }
         }
     }
 
-    /* Don't even try to load empty VM states */
-    ret = bdrv_snapshot_find(bs, &sn, name);
-    if ((ret >= 0) && (sn.vm_state_size == 0))
-        return -EINVAL;
-
     /* restore the VM state */
-    f = qemu_fopen_bdrv(bs, 0);
+    f = qemu_fopen_bdrv(bs_vm_state, 0);
     if (!f) {
-        monitor_printf(mon, "Could not open VM state file\n");
+        error_report("Could not open VM state file");
         return -EINVAL;
     }
+
+    qemu_system_reset(VMRESET_SILENT);
     ret = qemu_loadvm_state(f);
+
     qemu_fclose(f);
     if (ret < 0) {
-        monitor_printf(mon, "Error %d while loading VM state\n", ret);
+        error_report("Error %d while loading VM state", ret);
         return ret;
     }
+
     return 0;
 }
 
 void do_delvm(Monitor *mon, const QDict *qdict)
 {
-    DriveInfo *dinfo;
     BlockDriverState *bs, *bs1;
     int ret;
     const char *name = qdict_get_str(qdict, "name");
 
-    bs = get_bs_snapshots();
+    bs = bdrv_snapshots();
     if (!bs) {
         monitor_printf(mon, "No block device supports snapshots\n");
         return;
     }
 
-    QTAILQ_FOREACH(dinfo, &drives, next) {
-        bs1 = dinfo->bdrv;
-        if (bdrv_has_snapshot(bs1)) {
+    bs1 = NULL;
+    while ((bs1 = bdrv_next(bs1))) {
+        if (bdrv_can_snapshot(bs1)) {
             ret = bdrv_snapshot_delete(bs1, name);
             if (ret < 0) {
                 if (ret == -ENOTSUP)
@@ -1793,38 +2116,64 @@ void do_delvm(Monitor *mon, const QDict *qdict)
 
 void do_info_snapshots(Monitor *mon)
 {
-    DriveInfo *dinfo;
     BlockDriverState *bs, *bs1;
-    QEMUSnapshotInfo *sn_tab, *sn;
-    int nb_sns, i;
+    QEMUSnapshotInfo *sn_tab, *sn, s, *sn_info = &s;
+    int nb_sns, i, ret, available;
+    int total;
+    int *available_snapshots;
     char buf[256];
 
-    bs = get_bs_snapshots();
+    bs = bdrv_snapshots();
     if (!bs) {
         monitor_printf(mon, "No available block device supports snapshots\n");
         return;
     }
-    monitor_printf(mon, "Snapshot devices:");
-    QTAILQ_FOREACH(dinfo, &drives, next) {
-        bs1 = dinfo->bdrv;
-        if (bdrv_has_snapshot(bs1)) {
-            if (bs == bs1)
-                monitor_printf(mon, " %s", bdrv_get_device_name(bs1));
-        }
-    }
-    monitor_printf(mon, "\n");
 
     nb_sns = bdrv_snapshot_list(bs, &sn_tab);
     if (nb_sns < 0) {
         monitor_printf(mon, "bdrv_snapshot_list: error %d\n", nb_sns);
         return;
     }
-    monitor_printf(mon, "Snapshot list (from %s):\n",
-                   bdrv_get_device_name(bs));
-    monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL));
-    for(i = 0; i < nb_sns; i++) {
+
+    if (nb_sns == 0) {
+        monitor_printf(mon, "There is no snapshot available.\n");
+        return;
+    }
+
+    available_snapshots = qemu_mallocz(sizeof(int) * nb_sns);
+    total = 0;
+    for (i = 0; i < nb_sns; i++) {
         sn = &sn_tab[i];
-        monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn));
+        available = 1;
+        bs1 = NULL;
+
+        while ((bs1 = bdrv_next(bs1))) {
+            if (bdrv_can_snapshot(bs1) && bs1 != bs) {
+                ret = bdrv_snapshot_find(bs1, sn_info, sn->id_str);
+                if (ret < 0) {
+                    available = 0;
+                    break;
+                }
+            }
+        }
+
+        if (available) {
+            available_snapshots[total] = i;
+            total++;
+        }
     }
+
+    if (total > 0) {
+        monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL));
+        for (i = 0; i < total; i++) {
+            sn = &sn_tab[available_snapshots[i]];
+            monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn));
+        }
+    } else {
+        monitor_printf(mon, "There is no suitable snapshot available\n");
+    }
+
     qemu_free(sn_tab);
+    qemu_free(available_snapshots);
+
 }