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xemu/migration/savevm.c
Markus Armbruster 3ddba9a9e9 migration: Replace migration's JSON writer by the general one 
Commit 8118f0950f "migration: Append JSON description of migration
stream" needs a JSON writer.  The existing qobject_to_json() wasn't a
good fit, because it requires building a QObject to convert.  Instead,
migration got its very own JSON writer, in commit 190c882ce2 "QJSON:
Add JSON writer".  It tacitly limits numbers to int64_t, and strings
contents to characters that don't need escaping, unlike
qobject_to_json().

The previous commit factored the JSON writer out of qobject_to_json().
Replace migration's JSON writer by it.

Cc: Juan Quintela <quintela@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20201211171152.146877-17-armbru@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-12-19 10:39:16 +01:00

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/*
* 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 "qemu/osdep.h"
#include "hw/boards.h"
#include "net/net.h"
#include "migration.h"
#include "migration/snapshot.h"
#include "migration/vmstate.h"
#include "migration/misc.h"
#include "migration/register.h"
#include "migration/global_state.h"
#include "ram.h"
#include "qemu-file-channel.h"
#include "qemu-file.h"
#include "savevm.h"
#include "postcopy-ram.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-migration.h"
#include "qapi/qmp/json-writer.h"
#include "qapi/qmp/qerror.h"
#include "qemu/error-report.h"
#include "sysemu/cpus.h"
#include "exec/memory.h"
#include "exec/target_page.h"
#include "trace.h"
#include "qemu/iov.h"
#include "qemu/main-loop.h"
#include "block/snapshot.h"
#include "qemu/cutils.h"
#include "io/channel-buffer.h"
#include "io/channel-file.h"
#include "sysemu/replay.h"
#include "sysemu/runstate.h"
#include "sysemu/sysemu.h"
#include "sysemu/xen.h"
#include "migration/colo.h"
#include "qemu/bitmap.h"
#include "net/announce.h"
const unsigned int postcopy_ram_discard_version;
/* Subcommands for QEMU_VM_COMMAND */
enum qemu_vm_cmd {
MIG_CMD_INVALID = 0, /* Must be 0 */
MIG_CMD_OPEN_RETURN_PATH, /* Tell the dest to open the Return path */
MIG_CMD_PING, /* Request a PONG on the RP */
MIG_CMD_POSTCOPY_ADVISE, /* Prior to any page transfers, just
warn we might want to do PC */
MIG_CMD_POSTCOPY_LISTEN, /* Start listening for incoming
pages as it's running. */
MIG_CMD_POSTCOPY_RUN, /* Start execution */
MIG_CMD_POSTCOPY_RAM_DISCARD, /* A list of pages to discard that
were previously sent during
precopy but are dirty. */
MIG_CMD_PACKAGED, /* Send a wrapped stream within this stream */
MIG_CMD_ENABLE_COLO, /* Enable COLO */
MIG_CMD_POSTCOPY_RESUME, /* resume postcopy on dest */
MIG_CMD_RECV_BITMAP, /* Request for recved bitmap on dst */
MIG_CMD_MAX
};
#define MAX_VM_CMD_PACKAGED_SIZE UINT32_MAX
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 = -1, .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_POSTCOPY_RESUME] = { .len = 0, .name = "POSTCOPY_RESUME" },
[MIG_CMD_PACKAGED] = { .len = 4, .name = "PACKAGED" },
[MIG_CMD_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" },
[MIG_CMD_MAX] = { .len = -1, .name = "MAX" },
};
/* Note for MIG_CMD_POSTCOPY_ADVISE:
* The format of arguments is depending on postcopy mode:
* - postcopy RAM only
* uint64_t host page size
* uint64_t taget page size
*
* - postcopy RAM and postcopy dirty bitmaps
* format is the same as for postcopy RAM only
*
* - postcopy dirty bitmaps only
* Nothing. Command length field is 0.
*
* Be careful: adding a new postcopy entity with some other parameters should
* not break format self-description ability. Good way is to introduce some
* generic extendable format with an exception for two old entities.
*/
/***********************************************************/
/* savevm/loadvm support */
static ssize_t block_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
int64_t pos, Error **errp)
{
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_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
size_t size, Error **errp)
{
return bdrv_load_vmstate(opaque, buf, pos, size);
}
static int bdrv_fclose(void *opaque, Error **errp)
{
return bdrv_flush(opaque);
}
static const QEMUFileOps bdrv_read_ops = {
.get_buffer = block_get_buffer,
.close = bdrv_fclose
};
static const QEMUFileOps bdrv_write_ops = {
.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,
const VMStateField *field)
{
QEMUTimer *v = pv;
timer_get(f, v);
return 0;
}
static int put_timer(QEMUFile *f, void *pv, size_t size,
const VMStateField *field, JSONWriter *vmdesc)
{
QEMUTimer *v = pv;
timer_put(f, v);
return 0;
}
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];
uint32_t instance_id;
int alias_id;
int version_id;
/* version id read from the stream */
int load_version_id;
int section_id;
/* section id read from the stream */
int load_section_id;
const SaveVMHandlers *ops;
const VMStateDescription *vmsd;
void *opaque;
CompatEntry *compat;
int is_ram;
} SaveStateEntry;
typedef struct SaveState {
QTAILQ_HEAD(, SaveStateEntry) handlers;
SaveStateEntry *handler_pri_head[MIG_PRI_MAX + 1];
int global_section_id;
uint32_t len;
const char *name;
uint32_t target_page_bits;
uint32_t caps_count;
MigrationCapability *capabilities;
QemuUUID uuid;
} SaveState;
static SaveState savevm_state = {
.handlers = QTAILQ_HEAD_INITIALIZER(savevm_state.handlers),
.handler_pri_head = { [MIG_PRI_DEFAULT ... MIG_PRI_MAX] = NULL },
.global_section_id = 0,
};
static bool should_validate_capability(int capability)
{
assert(capability >= 0 && capability < MIGRATION_CAPABILITY__MAX);
/* Validate only new capabilities to keep compatibility. */
switch (capability) {
case MIGRATION_CAPABILITY_X_IGNORE_SHARED:
return true;
default:
return false;
}
}
static uint32_t get_validatable_capabilities_count(void)
{
MigrationState *s = migrate_get_current();
uint32_t result = 0;
int i;
for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
if (should_validate_capability(i) && s->enabled_capabilities[i]) {
result++;
}
}
return result;
}
static int configuration_pre_save(void *opaque)
{
SaveState *state = opaque;
const char *current_name = MACHINE_GET_CLASS(current_machine)->name;
MigrationState *s = migrate_get_current();
int i, j;
state->len = strlen(current_name);
state->name = current_name;
state->target_page_bits = qemu_target_page_bits();
state->caps_count = get_validatable_capabilities_count();
state->capabilities = g_renew(MigrationCapability, state->capabilities,
state->caps_count);
for (i = j = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
if (should_validate_capability(i) && s->enabled_capabilities[i]) {
state->capabilities[j++] = i;
}
}
state->uuid = qemu_uuid;
return 0;
}
static int configuration_pre_load(void *opaque)
{
SaveState *state = opaque;
/* If there is no target-page-bits subsection it means the source
* predates the variable-target-page-bits support and is using the
* minimum possible value for this CPU.
*/
state->target_page_bits = qemu_target_page_bits_min();
return 0;
}
static bool configuration_validate_capabilities(SaveState *state)
{
bool ret = true;
MigrationState *s = migrate_get_current();
unsigned long *source_caps_bm;
int i;
source_caps_bm = bitmap_new(MIGRATION_CAPABILITY__MAX);
for (i = 0; i < state->caps_count; i++) {
MigrationCapability capability = state->capabilities[i];
set_bit(capability, source_caps_bm);
}
for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
bool source_state, target_state;
if (!should_validate_capability(i)) {
continue;
}
source_state = test_bit(i, source_caps_bm);
target_state = s->enabled_capabilities[i];
if (source_state != target_state) {
error_report("Capability %s is %s, but received capability is %s",
MigrationCapability_str(i),
target_state ? "on" : "off",
source_state ? "on" : "off");
ret = false;
/* Don't break here to report all failed capabilities */
}
}
g_free(source_caps_bm);
return ret;
}
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'",
(int) state->len, state->name, current_name);
return -EINVAL;
}
if (state->target_page_bits != qemu_target_page_bits()) {
error_report("Received TARGET_PAGE_BITS is %d but local is %d",
state->target_page_bits, qemu_target_page_bits());
return -EINVAL;
}
if (!configuration_validate_capabilities(state)) {
return -EINVAL;
}
return 0;
}
static int get_capability(QEMUFile *f, void *pv, size_t size,
const VMStateField *field)
{
MigrationCapability *capability = pv;
char capability_str[UINT8_MAX + 1];
uint8_t len;
int i;
len = qemu_get_byte(f);
qemu_get_buffer(f, (uint8_t *)capability_str, len);
capability_str[len] = '\0';
for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
if (!strcmp(MigrationCapability_str(i), capability_str)) {
*capability = i;
return 0;
}
}
error_report("Received unknown capability %s", capability_str);
return -EINVAL;
}
static int put_capability(QEMUFile *f, void *pv, size_t size,
const VMStateField *field, JSONWriter *vmdesc)
{
MigrationCapability *capability = pv;
const char *capability_str = MigrationCapability_str(*capability);
size_t len = strlen(capability_str);
assert(len <= UINT8_MAX);
qemu_put_byte(f, len);
qemu_put_buffer(f, (uint8_t *)capability_str, len);
return 0;
}
static const VMStateInfo vmstate_info_capability = {
.name = "capability",
.get = get_capability,
.put = put_capability,
};
/* The target-page-bits subsection is present only if the
* target page size is not the same as the default (ie the
* minimum page size for a variable-page-size guest CPU).
* If it is present then it contains the actual target page
* bits for the machine, and migration will fail if the
* two ends don't agree about it.
*/
static bool vmstate_target_page_bits_needed(void *opaque)
{
return qemu_target_page_bits()
> qemu_target_page_bits_min();
}
static const VMStateDescription vmstate_target_page_bits = {
.name = "configuration/target-page-bits",
.version_id = 1,
.minimum_version_id = 1,
.needed = vmstate_target_page_bits_needed,
.fields = (VMStateField[]) {
VMSTATE_UINT32(target_page_bits, SaveState),
VMSTATE_END_OF_LIST()
}
};
static bool vmstate_capabilites_needed(void *opaque)
{
return get_validatable_capabilities_count() > 0;
}
static const VMStateDescription vmstate_capabilites = {
.name = "configuration/capabilities",
.version_id = 1,
.minimum_version_id = 1,
.needed = vmstate_capabilites_needed,
.fields = (VMStateField[]) {
VMSTATE_UINT32_V(caps_count, SaveState, 1),
VMSTATE_VARRAY_UINT32_ALLOC(capabilities, SaveState, caps_count, 1,
vmstate_info_capability,
MigrationCapability),
VMSTATE_END_OF_LIST()
}
};
static bool vmstate_uuid_needed(void *opaque)
{
return qemu_uuid_set && migrate_validate_uuid();
}
static int vmstate_uuid_post_load(void *opaque, int version_id)
{
SaveState *state = opaque;
char uuid_src[UUID_FMT_LEN + 1];
char uuid_dst[UUID_FMT_LEN + 1];
if (!qemu_uuid_set) {
/*
* It's warning because user might not know UUID in some cases,
* e.g. load an old snapshot
*/
qemu_uuid_unparse(&state->uuid, uuid_src);
warn_report("UUID is received %s, but local uuid isn't set",
uuid_src);
return 0;
}
if (!qemu_uuid_is_equal(&state->uuid, &qemu_uuid)) {
qemu_uuid_unparse(&state->uuid, uuid_src);
qemu_uuid_unparse(&qemu_uuid, uuid_dst);
error_report("UUID received is %s and local is %s", uuid_src, uuid_dst);
return -EINVAL;
}
return 0;
}
static const VMStateDescription vmstate_uuid = {
.name = "configuration/uuid",
.version_id = 1,
.minimum_version_id = 1,
.needed = vmstate_uuid_needed,
.post_load = vmstate_uuid_post_load,
.fields = (VMStateField[]) {
VMSTATE_UINT8_ARRAY_V(uuid.data, SaveState, sizeof(QemuUUID), 1),
VMSTATE_END_OF_LIST()
}
};
static const VMStateDescription vmstate_configuration = {
.name = "configuration",
.version_id = 1,
.pre_load = configuration_pre_load,
.post_load = configuration_post_load,
.pre_save = configuration_pre_save,
.fields = (VMStateField[]) {
VMSTATE_UINT32(len, SaveState),
VMSTATE_VBUFFER_ALLOC_UINT32(name, SaveState, 0, NULL, len),
VMSTATE_END_OF_LIST()
},
.subsections = (const VMStateDescription *[]) {
&vmstate_target_page_bits,
&vmstate_capabilites,
&vmstate_uuid,
NULL
}
};
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);
g_slist_free(list);
}
static uint32_t calculate_new_instance_id(const char *idstr)
{
SaveStateEntry *se;
uint32_t 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;
}
}
/* Make sure we never loop over without being noticed */
assert(instance_id != VMSTATE_INSTANCE_ID_ANY);
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;
}
static inline MigrationPriority save_state_priority(SaveStateEntry *se)
{
if (se->vmsd) {
return se->vmsd->priority;
}
return MIG_PRI_DEFAULT;
}
static void savevm_state_handler_insert(SaveStateEntry *nse)
{
MigrationPriority priority = save_state_priority(nse);
SaveStateEntry *se;
int i;
assert(priority <= MIG_PRI_MAX);
for (i = priority - 1; i >= 0; i--) {
se = savevm_state.handler_pri_head[i];
if (se != NULL) {
assert(save_state_priority(se) < priority);
break;
}
}
if (i >= 0) {
QTAILQ_INSERT_BEFORE(se, nse, entry);
} else {
QTAILQ_INSERT_TAIL(&savevm_state.handlers, nse, entry);
}
if (savevm_state.handler_pri_head[priority] == NULL) {
savevm_state.handler_pri_head[priority] = nse;
}
}
static void savevm_state_handler_remove(SaveStateEntry *se)
{
SaveStateEntry *next;
MigrationPriority priority = save_state_priority(se);
if (se == savevm_state.handler_pri_head[priority]) {
next = QTAILQ_NEXT(se, entry);
if (next != NULL && save_state_priority(next) == priority) {
savevm_state.handler_pri_head[priority] = next;
} else {
savevm_state.handler_pri_head[priority] = NULL;
}
}
QTAILQ_REMOVE(&savevm_state.handlers, se, entry);
}
/* 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,
uint32_t instance_id,
int version_id,
const 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_setup != NULL) {
se->is_ram = 1;
}
pstrcat(se->idstr, sizeof(se->idstr), idstr);
if (instance_id == VMSTATE_INSTANCE_ID_ANY) {
se->instance_id = calculate_new_instance_id(se->idstr);
} else {
se->instance_id = instance_id;
}
assert(!se->compat || se->instance_id == 0);
savevm_state_handler_insert(se);
return 0;
}
void unregister_savevm(VMStateIf *obj, const char *idstr, void *opaque)
{
SaveStateEntry *se, *new_se;
char id[256] = "";
if (obj) {
char *oid = vmstate_if_get_id(obj);
if (oid) {
pstrcpy(id, sizeof(id), oid);
pstrcat(id, sizeof(id), "/");
g_free(oid);
}
}
pstrcat(id, sizeof(id), idstr);
QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) {
if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) {
savevm_state_handler_remove(se);
g_free(se->compat);
g_free(se);
}
}
}
int vmstate_register_with_alias_id(VMStateIf *obj, uint32_t instance_id,
const VMStateDescription *vmsd,
void *opaque, int alias_id,
int required_for_version,
Error **errp)
{
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 (obj) {
char *id = vmstate_if_get_id(obj);
if (id) {
if (snprintf(se->idstr, sizeof(se->idstr), "%s/", id) >=
sizeof(se->idstr)) {
error_setg(errp, "Path too long for VMState (%s)", id);
g_free(id);
g_free(se);
return -1;
}
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 == VMSTATE_INSTANCE_ID_ANY ?
calculate_compat_instance_id(vmsd->name) : instance_id;
instance_id = VMSTATE_INSTANCE_ID_ANY;
}
}
pstrcat(se->idstr, sizeof(se->idstr), vmsd->name);
if (instance_id == VMSTATE_INSTANCE_ID_ANY) {
se->instance_id = calculate_new_instance_id(se->idstr);
} else {
se->instance_id = instance_id;
}
assert(!se->compat || se->instance_id == 0);
savevm_state_handler_insert(se);
return 0;
}
void vmstate_unregister(VMStateIf *obj, 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) {
savevm_state_handler_remove(se);
g_free(se->compat);
g_free(se);
}
}
}
static int vmstate_load(QEMUFile *f, SaveStateEntry *se)
{
trace_vmstate_load(se->idstr, se->vmsd ? se->vmsd->name : "(old)");
if (!se->vmsd) { /* Old style */
return se->ops->load_state(f, se->opaque, se->load_version_id);
}
return vmstate_load_state(f, se->vmsd, se->opaque, se->load_version_id);
}
static void vmstate_save_old_style(QEMUFile *f, SaveStateEntry *se,
JSONWriter *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_writer_int64(vmdesc, "size", size);
json_writer_start_array(vmdesc, "fields");
json_writer_start_object(vmdesc, NULL);
json_writer_str(vmdesc, "name", "data");
json_writer_int64(vmdesc, "size", size);
json_writer_str(vmdesc, "type", "buffer");
json_writer_end_object(vmdesc);
json_writer_end_array(vmdesc);
}
}
static int vmstate_save(QEMUFile *f, SaveStateEntry *se,
JSONWriter *vmdesc)
{
trace_vmstate_save(se->idstr, se->vmsd ? se->vmsd->name : "(old)");
if (!se->vmsd) {
vmstate_save_old_style(f, se, vmdesc);
return 0;
}
return vmstate_save_state(f, se->vmsd, se->opaque, vmdesc);
}
/*
* 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 (migrate_get_current()->send_section_footer) {
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.
*/
static 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_colo_enable(QEMUFile *f)
{
trace_savevm_send_colo_enable();
qemu_savevm_command_send(f, MIG_CMD_ENABLE_COLO, 0, NULL);
}
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 uint8_t *buf, size_t len)
{
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);
qemu_put_buffer(f, buf, len);
return 0;
}
/* Send prior to any postcopy transfer */
void qemu_savevm_send_postcopy_advise(QEMUFile *f)
{
if (migrate_postcopy_ram()) {
uint64_t tmp[2];
tmp[0] = cpu_to_be64(ram_pagesize_summary());
tmp[1] = cpu_to_be64(qemu_target_page_size());
trace_qemu_savevm_send_postcopy_advise();
qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_ADVISE,
16, (uint8_t *)tmp);
} else {
qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_ADVISE, 0, NULL);
}
}
/* 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++) {
stq_be_p(buf + tmplen, start_list[t]);
tmplen += 8;
stq_be_p(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);
}
void qemu_savevm_send_postcopy_resume(QEMUFile *f)
{
trace_savevm_send_postcopy_resume();
qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RESUME, 0, NULL);
}
void qemu_savevm_send_recv_bitmap(QEMUFile *f, char *block_name)
{
size_t len;
char buf[256];
trace_savevm_send_recv_bitmap(block_name);
buf[0] = len = strlen(block_name);
memcpy(buf + 1, block_name, len);
qemu_savevm_command_send(f, MIG_CMD_RECV_BITMAP, len + 1, (uint8_t *)buf);
}
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;
}
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 (migrate_get_current()->send_configuration) {
qemu_put_byte(f, QEMU_VM_CONFIGURATION);
vmstate_save_state(f, &vmstate_configuration, &savevm_state, 0);
}
}
bool qemu_savevm_state_guest_unplug_pending(void)
{
SaveStateEntry *se;
QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
if (se->vmsd && se->vmsd->dev_unplug_pending &&
se->vmsd->dev_unplug_pending(se->opaque)) {
return true;
}
}
return false;
}
void qemu_savevm_state_setup(QEMUFile *f)
{
SaveStateEntry *se;
Error *local_err = NULL;
int ret;
trace_savevm_state_setup();
QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
if (!se->ops || !se->ops->save_setup) {
continue;
}
if (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_setup(f, se->opaque);
save_section_footer(f, se);
if (ret < 0) {
qemu_file_set_error(f, ret);
break;
}
}
if (precopy_notify(PRECOPY_NOTIFY_SETUP, &local_err)) {
error_report_err(local_err);
}
}
int qemu_savevm_state_resume_prepare(MigrationState *s)
{
SaveStateEntry *se;
int ret;
trace_savevm_state_resume_prepare();
QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
if (!se->ops || !se->ops->resume_prepare) {
continue;
}
if (se->ops->is_active) {
if (!se->ops->is_active(se->opaque)) {
continue;
}
}
ret = se->ops->resume_prepare(s, se->opaque);
if (ret < 0) {
return ret;
}
}
return 0;
}
/*
* 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->is_active &&
!se->ops->is_active(se->opaque)) {
continue;
}
if (se->ops->is_active_iterate &&
!se->ops->is_active_iterate(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->has_postcopy && se->ops->has_postcopy(se->opaque))) {
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) {
error_report("failed to save SaveStateEntry with id(name): %d(%s)",
se->section_id, se->idstr);
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();
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->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);
}
static
int qemu_savevm_state_complete_precopy_iterable(QEMUFile *f, bool in_postcopy)
{
SaveStateEntry *se;
int ret;
QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
if (!se->ops ||
(in_postcopy && se->ops->has_postcopy &&
se->ops->has_postcopy(se->opaque)) ||
!se->ops->save_live_complete_precopy) {
continue;
}
if (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 -1;
}
}
return 0;
}
static
int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f,
bool in_postcopy,
bool inactivate_disks)
{
g_autoptr(JSONWriter) vmdesc = NULL;
int vmdesc_len;
SaveStateEntry *se;
int ret;
vmdesc = json_writer_new(false);
json_writer_start_object(vmdesc, NULL);
json_writer_int64(vmdesc, "page_size", qemu_target_page_size());
json_writer_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_writer_start_object(vmdesc, NULL);
json_writer_str(vmdesc, "name", se->idstr);
json_writer_int64(vmdesc, "instance_id", se->instance_id);
save_section_header(f, se, QEMU_VM_SECTION_FULL);
ret = vmstate_save(f, se, vmdesc);
if (ret) {
qemu_file_set_error(f, ret);
return ret;
}
trace_savevm_section_end(se->idstr, se->section_id, 0);
save_section_footer(f, se);
json_writer_end_object(vmdesc);
}
if (inactivate_disks) {
/* Inactivate before sending QEMU_VM_EOF so that the
* bdrv_invalidate_cache_all() on the other end won't fail. */
ret = bdrv_inactivate_all();
if (ret) {
error_report("%s: bdrv_inactivate_all() failed (%d)",
__func__, ret);
qemu_file_set_error(f, ret);
return ret;
}
}
if (!in_postcopy) {
/* Postcopy stream will still be going */
qemu_put_byte(f, QEMU_VM_EOF);
}
json_writer_end_array(vmdesc);
json_writer_end_object(vmdesc);
vmdesc_len = strlen(json_writer_get(vmdesc));
if (should_send_vmdesc()) {
qemu_put_byte(f, QEMU_VM_VMDESCRIPTION);
qemu_put_be32(f, vmdesc_len);
qemu_put_buffer(f, (uint8_t *)json_writer_get(vmdesc), vmdesc_len);
}
return 0;
}
int qemu_savevm_state_complete_precopy(QEMUFile *f, bool iterable_only,
bool inactivate_disks)
{
int ret;
Error *local_err = NULL;
bool in_postcopy = migration_in_postcopy();
if (precopy_notify(PRECOPY_NOTIFY_COMPLETE, &local_err)) {
error_report_err(local_err);
}
trace_savevm_state_complete_precopy();
cpu_synchronize_all_states();
if (!in_postcopy || iterable_only) {
ret = qemu_savevm_state_complete_precopy_iterable(f, in_postcopy);
if (ret) {
return ret;
}
}
if (iterable_only) {
goto flush;
}
ret = qemu_savevm_state_complete_precopy_non_iterable(f, in_postcopy,
inactivate_disks);
if (ret) {
return ret;
}
flush:
qemu_fflush(f);
return 0;
}
/* 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 threshold_size,
uint64_t *res_precopy_only,
uint64_t *res_compatible,
uint64_t *res_postcopy_only)
{
SaveStateEntry *se;
*res_precopy_only = 0;
*res_compatible = 0;
*res_postcopy_only = 0;
QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
if (!se->ops || !se->ops->save_live_pending) {
continue;
}
if (se->ops->is_active) {
if (!se->ops->is_active(se->opaque)) {
continue;
}
}
se->ops->save_live_pending(f, se->opaque, threshold_size,
res_precopy_only, res_compatible,
res_postcopy_only);
}
}
void qemu_savevm_state_cleanup(void)
{
SaveStateEntry *se;
Error *local_err = NULL;
if (precopy_notify(PRECOPY_NOTIFY_CLEANUP, &local_err)) {
error_report_err(local_err);
}
trace_savevm_state_cleanup();
QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
if (se->ops && se->ops->save_cleanup) {
se->ops->save_cleanup(se->opaque);
}
}
}
static int qemu_savevm_state(QEMUFile *f, Error **errp)
{
int ret;
MigrationState *ms = migrate_get_current();
MigrationStatus status;
if (migration_is_running(ms->state)) {
error_setg(errp, QERR_MIGRATION_ACTIVE);
return -EINVAL;
}
if (migrate_use_block()) {
error_setg(errp, "Block migration and snapshots are incompatible");
return -EINVAL;
}
migrate_init(ms);
memset(&ram_counters, 0, sizeof(ram_counters));
ms->to_dst_file = f;
qemu_mutex_unlock_iothread();
qemu_savevm_state_header(f);
qemu_savevm_state_setup(f);
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, false);
ret = qemu_file_get_error(f);
}
qemu_savevm_state_cleanup();
if (ret != 0) {
error_setg_errno(errp, -ret, "Error while writing VM state");
}
if (ret != 0) {
status = MIGRATION_STATUS_FAILED;
} else {
status = MIGRATION_STATUS_COMPLETED;
}
migrate_set_state(&ms->state, MIGRATION_STATUS_SETUP, status);
/* f is outer parameter, it should not stay in global migration state after
* this function finished */
ms->to_dst_file = NULL;
return ret;
}
void qemu_savevm_live_state(QEMUFile *f)
{
/* save QEMU_VM_SECTION_END section */
qemu_savevm_state_complete_precopy(f, true, false);
qemu_put_byte(f, QEMU_VM_EOF);
}
int qemu_save_device_state(QEMUFile *f)
{
SaveStateEntry *se;
if (!migration_in_colo_state()) {
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) {
int ret;
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);
ret = vmstate_save(f, se, NULL);
if (ret) {
return ret;
}
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, uint32_t 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,
};
/* ------ 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,
uint16_t len)
{
PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_ADVISE);
uint64_t remote_pagesize_summary, local_pagesize_summary, remote_tps;
Error *local_err = NULL;
trace_loadvm_postcopy_handle_advise();
if (ps != POSTCOPY_INCOMING_NONE) {
error_report("CMD_POSTCOPY_ADVISE in wrong postcopy state (%d)", ps);
return -1;
}
switch (len) {
case 0:
if (migrate_postcopy_ram()) {
error_report("RAM postcopy is enabled but have 0 byte advise");
return -EINVAL;
}
return 0;
case 8 + 8:
if (!migrate_postcopy_ram()) {
error_report("RAM postcopy is disabled but have 16 byte advise");
return -EINVAL;
}
break;
default:
error_report("CMD_POSTCOPY_ADVISE invalid length (%d)", len);
return -EINVAL;
}
if (!postcopy_ram_supported_by_host(mis)) {
postcopy_state_set(POSTCOPY_INCOMING_NONE);
return -1;
}
remote_pagesize_summary = qemu_get_be64(mis->from_src_file);
local_pagesize_summary = ram_pagesize_summary();
if (remote_pagesize_summary != local_pagesize_summary) {
/*
* This detects two potential causes of mismatch:
* a) A mismatch in host page sizes
* 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.
* b) The use of different huge page sizes on source/destination
* a more fine grain test is performed during RAM block migration
* but this test here causes a nice early clear failure, and
* also fails when passed to an older qemu that doesn't
* do huge pages.
*/
error_report("Postcopy needs matching RAM page sizes (s=%" PRIx64
" d=%" PRIx64 ")",
remote_pagesize_summary, local_pagesize_summary);
return -1;
}
remote_tps = qemu_get_be64(mis->from_src_file);
if (remote_tps != qemu_target_page_size()) {
/*
* Again, some differences could be dealt with, but for now keep it
* simple.
*/
error_report("Postcopy needs matching target page sizes (s=%d d=%zd)",
(int)remote_tps, qemu_target_page_size());
return -1;
}
if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_ADVISE, &local_err)) {
error_report_err(local_err);
return -1;
}
if (ram_postcopy_incoming_init(mis)) {
return -1;
}
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(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)
{
MigrationIncomingState *mis = migration_incoming_get_current();
QEMUFile *f = mis->from_src_file;
int load_res;
MigrationState *migr = migrate_get_current();
object_ref(OBJECT(migr));
migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_POSTCOPY_ACTIVE);
qemu_sem_post(&mis->listen_thread_sem);
trace_postcopy_ram_listen_thread_start();
rcu_register_thread();
/*
* 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);
/*
* This is tricky, but, mis->from_src_file can change after it
* returns, when postcopy recovery happened. In the future, we may
* want a wrapper for the QEMUFile handle.
*/
f = mis->from_src_file;
/* 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) {
qemu_file_set_error(f, load_res);
dirty_bitmap_mig_cancel_incoming();
if (postcopy_state_get() == POSTCOPY_INCOMING_RUNNING &&
!migrate_postcopy_ram() && migrate_dirty_bitmaps())
{
error_report("%s: loadvm failed during postcopy: %d. All states "
"are migrated except dirty bitmaps. Some dirty "
"bitmaps may be lost, and present migrated dirty "
"bitmaps are correctly migrated and valid.",
__func__, load_res);
load_res = 0; /* prevent further exit() */
} else {
error_report("%s: loadvm failed: %d", __func__, load_res);
migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
MIGRATION_STATUS_FAILED);
}
}
if (load_res >= 0) {
/*
* 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 (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.
*/
rcu_unregister_thread();
exit(EXIT_FAILURE);
}
migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
MIGRATION_STATUS_COMPLETED);
/*
* 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();
qemu_loadvm_state_cleanup();
rcu_unregister_thread();
mis->have_listen_thread = false;
postcopy_state_set(POSTCOPY_INCOMING_END);
object_unref(OBJECT(migr));
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();
Error *local_err = NULL;
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.
*/
if (migrate_postcopy_ram()) {
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 (migrate_postcopy_ram()) {
if (postcopy_ram_incoming_setup(mis)) {
postcopy_ram_incoming_cleanup(mis);
return -1;
}
}
if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_LISTEN, &local_err)) {
error_report_err(local_err);
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, NULL,
QEMU_THREAD_DETACHED);
qemu_sem_wait(&mis->listen_thread_sem);
qemu_sem_destroy(&mis->listen_thread_sem);
return 0;
}
static void loadvm_postcopy_handle_run_bh(void *opaque)
{
Error *local_err = NULL;
MigrationIncomingState *mis = opaque;
/* 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(&mis->announce_timer, migrate_announce_params());
/* Make sure all file formats flush their mutable metadata.
* If we get an error here, just don't restart the VM yet. */
bdrv_invalidate_cache_all(&local_err);
if (local_err) {
error_report_err(local_err);
local_err = NULL;
autostart = false;
}
trace_loadvm_postcopy_handle_run_cpu_sync();
trace_loadvm_postcopy_handle_run_vmstart();
dirty_bitmap_mig_before_vm_start();
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);
}
qemu_bh_delete(mis->bh);
}
/* After all discards we can start running and asking for pages */
static int loadvm_postcopy_handle_run(MigrationIncomingState *mis)
{
PostcopyState ps = postcopy_state_get();
trace_loadvm_postcopy_handle_run();
if (ps != POSTCOPY_INCOMING_LISTENING) {
error_report("CMD_POSTCOPY_RUN in wrong postcopy state (%d)", ps);
return -1;
}
postcopy_state_set(POSTCOPY_INCOMING_RUNNING);
mis->bh = qemu_bh_new(loadvm_postcopy_handle_run_bh, mis);
qemu_bh_schedule(mis->bh);
/* 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;
}
/* We must be with page_request_mutex held */
static gboolean postcopy_sync_page_req(gpointer key, gpointer value,
gpointer data)
{
MigrationIncomingState *mis = data;
void *host_addr = (void *) key;
ram_addr_t rb_offset;
RAMBlock *rb;
int ret;
rb = qemu_ram_block_from_host(host_addr, true, &rb_offset);
if (!rb) {
/*
* This should _never_ happen. However be nice for a migrating VM to
* not crash/assert. Post an error (note: intended to not use *_once
* because we do want to see all the illegal addresses; and this can
* never be triggered by the guest so we're safe) and move on next.
*/
error_report("%s: illegal host addr %p", __func__, host_addr);
/* Try the next entry */
return FALSE;
}
ret = migrate_send_rp_message_req_pages(mis, rb, rb_offset);
if (ret) {
/* Please refer to above comment. */
error_report("%s: send rp message failed for addr %p",
__func__, host_addr);
return FALSE;
}
trace_postcopy_page_req_sync(host_addr);
return FALSE;
}
static void migrate_send_rp_req_pages_pending(MigrationIncomingState *mis)
{
WITH_QEMU_LOCK_GUARD(&mis->page_request_mutex) {
g_tree_foreach(mis->page_requested, postcopy_sync_page_req, mis);
}
}
static int loadvm_postcopy_handle_resume(MigrationIncomingState *mis)
{
if (mis->state != MIGRATION_STATUS_POSTCOPY_RECOVER) {
error_report("%s: illegal resume received", __func__);
/* Don't fail the load, only for this. */
return 0;
}
/*
* Reset the last_rb before we resend any page req to source again, since
* the source should have it reset already.
*/
mis->last_rb = NULL;
/*
* This means source VM is ready to resume the postcopy migration.
*/
migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_RECOVER,
MIGRATION_STATUS_POSTCOPY_ACTIVE);
trace_loadvm_postcopy_handle_resume();
/* Tell source that "we are ready" */
migrate_send_rp_resume_ack(mis, MIGRATION_RESUME_ACK_VALUE);
/*
* After a postcopy recovery, the source should have lost the postcopy
* queue, or potentially the requested pages could have been lost during
* the network down phase. Let's re-sync with the source VM by re-sending
* all the pending pages that we eagerly need, so these threads won't get
* blocked too long due to the recovery.
*
* Without this procedure, the faulted destination VM threads (waiting for
* page requests right before the postcopy is interrupted) can keep hanging
* until the pages are sent by the source during the background copying of
* pages, or another thread faulted on the same address accidentally.
*/
migrate_send_rp_req_pages_pending(mis);
/*
* It's time to switch state and release the fault thread to continue
* service page faults. Note that this should be explicitly after the
* above call to migrate_send_rp_req_pages_pending(). In short:
* migrate_send_rp_message_req_pages() is not thread safe, yet.
*/
qemu_sem_post(&mis->postcopy_pause_sem_fault);
return 0;
}
/**
* 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;
size_t length;
QIOChannelBuffer *bioc;
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: %zu", length);
return -1;
}
bioc = qio_channel_buffer_new(length);
qio_channel_set_name(QIO_CHANNEL(bioc), "migration-loadvm-buffer");
ret = qemu_get_buffer(mis->from_src_file,
bioc->data,
length);
if (ret != length) {
object_unref(OBJECT(bioc));
error_report("CMD_PACKAGED: Buffer receive fail ret=%d length=%zu",
ret, length);
return (ret < 0) ? ret : -EAGAIN;
}
bioc->usage += length;
trace_loadvm_handle_cmd_packaged_received(ret);
QEMUFile *packf = qemu_fopen_channel_input(QIO_CHANNEL(bioc));
ret = qemu_loadvm_state_main(packf, mis);
trace_loadvm_handle_cmd_packaged_main(ret);
qemu_fclose(packf);
object_unref(OBJECT(bioc));
return ret;
}
/*
* Handle request that source requests for recved_bitmap on
* destination. Payload format:
*
* len (1 byte) + ramblock_name (<255 bytes)
*/
static int loadvm_handle_recv_bitmap(MigrationIncomingState *mis,
uint16_t len)
{
QEMUFile *file = mis->from_src_file;
RAMBlock *rb;
char block_name[256];
size_t cnt;
cnt = qemu_get_counted_string(file, block_name);
if (!cnt) {
error_report("%s: failed to read block name", __func__);
return -EINVAL;
}
/* Validate before using the data */
if (qemu_file_get_error(file)) {
return qemu_file_get_error(file);
}
if (len != cnt + 1) {
error_report("%s: invalid payload length (%d)", __func__, len);
return -EINVAL;
}
rb = qemu_ram_block_by_name(block_name);
if (!rb) {
error_report("%s: block '%s' not found", __func__, block_name);
return -EINVAL;
}
migrate_send_rp_recv_bitmap(mis, block_name);
trace_loadvm_handle_recv_bitmap(block_name);
return 0;
}
static int loadvm_process_enable_colo(MigrationIncomingState *mis)
{
int ret = migration_incoming_enable_colo();
if (!ret) {
ret = colo_init_ram_cache();
if (ret) {
migration_incoming_disable_colo();
}
}
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);
/* Check validity before continue processing of cmds */
if (qemu_file_get_error(f)) {
return qemu_file_get_error(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, len);
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);
case MIG_CMD_POSTCOPY_RESUME:
return loadvm_postcopy_handle_resume(mis);
case MIG_CMD_RECV_BITMAP:
return loadvm_handle_recv_bitmap(mis, len);
case MIG_CMD_ENABLE_COLO:
return loadvm_process_enable_colo(mis);
}
return 0;
}
/*
* 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, SaveStateEntry *se)
{
int ret;
uint8_t read_mark;
uint32_t read_section_id;
if (!migrate_get_current()->send_section_footer) {
/* No footer to check */
return true;
}
read_mark = qemu_get_byte(f);
ret = qemu_file_get_error(f);
if (ret) {
error_report("%s: Read section footer failed: %d",
__func__, ret);
return false;
}
if (read_mark != QEMU_VM_SECTION_FOOTER) {
error_report("Missing section footer for %s", se->idstr);
return false;
}
read_section_id = qemu_get_be32(f);
if (read_section_id != se->load_section_id) {
error_report("Mismatched section id in footer for %s -"
" read 0x%x expected 0x%x",
se->idstr, read_section_id, se->load_section_id);
return false;
}
/* All good */
return true;
}
static int
qemu_loadvm_section_start_full(QEMUFile *f, MigrationIncomingState *mis)
{
uint32_t instance_id, version_id, section_id;
SaveStateEntry *se;
char idstr[256];
int ret;
/* 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);
ret = qemu_file_get_error(f);
if (ret) {
error_report("%s: Failed to read instance/version ID: %d",
__func__, ret);
return ret;
}
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' %"PRIu32". "
"Make sure that your current VM setup matches your "
"saved VM setup, including any hotplugged devices",
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;
}
se->load_version_id = version_id;
se->load_section_id = section_id;
/* Validate if it is a device's state */
if (xen_enabled() && se->is_ram) {
error_report("loadvm: %s RAM loading not allowed on Xen", idstr);
return -EINVAL;
}
ret = vmstate_load(f, se);
if (ret < 0) {
error_report("error while loading state for instance 0x%"PRIx32" of"
" device '%s'", instance_id, idstr);
return ret;
}
if (!check_section_footer(f, se)) {
return -EINVAL;
}
return 0;
}
static int
qemu_loadvm_section_part_end(QEMUFile *f, MigrationIncomingState *mis)
{
uint32_t section_id;
SaveStateEntry *se;
int ret;
section_id = qemu_get_be32(f);
ret = qemu_file_get_error(f);
if (ret) {
error_report("%s: Failed to read section ID: %d",
__func__, ret);
return ret;
}
trace_qemu_loadvm_state_section_partend(section_id);
QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
if (se->load_section_id == section_id) {
break;
}
}
if (se == NULL) {
error_report("Unknown savevm section %d", section_id);
return -EINVAL;
}
ret = vmstate_load(f, se);
if (ret < 0) {
error_report("error while loading state section id %d(%s)",
section_id, se->idstr);
return ret;
}
if (!check_section_footer(f, se)) {
return -EINVAL;
}
return 0;
}
static int qemu_loadvm_state_header(QEMUFile *f)
{
unsigned int v;
int ret;
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 (migrate_get_current()->send_configuration) {
if (qemu_get_byte(f) != QEMU_VM_CONFIGURATION) {
error_report("Configuration section missing");
qemu_loadvm_state_cleanup();
return -EINVAL;
}
ret = vmstate_load_state(f, &vmstate_configuration, &savevm_state, 0);
if (ret) {
qemu_loadvm_state_cleanup();
return ret;
}
}
return 0;
}
static int qemu_loadvm_state_setup(QEMUFile *f)
{
SaveStateEntry *se;
int ret;
trace_loadvm_state_setup();
QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
if (!se->ops || !se->ops->load_setup) {
continue;
}
if (se->ops->is_active) {
if (!se->ops->is_active(se->opaque)) {
continue;
}
}
ret = se->ops->load_setup(f, se->opaque);
if (ret < 0) {
qemu_file_set_error(f, ret);
error_report("Load state of device %s failed", se->idstr);
return ret;
}
}
return 0;
}
void qemu_loadvm_state_cleanup(void)
{
SaveStateEntry *se;
trace_loadvm_state_cleanup();
QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
if (se->ops && se->ops->load_cleanup) {
se->ops->load_cleanup(se->opaque);
}
}
}
/* Return true if we should continue the migration, or false. */
static bool postcopy_pause_incoming(MigrationIncomingState *mis)
{
trace_postcopy_pause_incoming();
assert(migrate_postcopy_ram());
/* Clear the triggered bit to allow one recovery */
mis->postcopy_recover_triggered = false;
assert(mis->from_src_file);
qemu_file_shutdown(mis->from_src_file);
qemu_fclose(mis->from_src_file);
mis->from_src_file = NULL;
assert(mis->to_src_file);
qemu_file_shutdown(mis->to_src_file);
qemu_mutex_lock(&mis->rp_mutex);
qemu_fclose(mis->to_src_file);
mis->to_src_file = NULL;
qemu_mutex_unlock(&mis->rp_mutex);
migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
MIGRATION_STATUS_POSTCOPY_PAUSED);
/* Notify the fault thread for the invalidated file handle */
postcopy_fault_thread_notify(mis);
error_report("Detected IO failure for postcopy. "
"Migration paused.");
while (mis->state == MIGRATION_STATUS_POSTCOPY_PAUSED) {
qemu_sem_wait(&mis->postcopy_pause_sem_dst);
}
trace_postcopy_pause_incoming_continued();
return true;
}
int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis)
{
uint8_t section_type;
int ret = 0;
retry:
while (true) {
section_type = qemu_get_byte(f);
if (qemu_file_get_error(f)) {
ret = qemu_file_get_error(f);
break;
}
trace_qemu_loadvm_state_section(section_type);
switch (section_type) {
case QEMU_VM_SECTION_START:
case QEMU_VM_SECTION_FULL:
ret = qemu_loadvm_section_start_full(f, mis);
if (ret < 0) {
goto out;
}
break;
case QEMU_VM_SECTION_PART:
case QEMU_VM_SECTION_END:
ret = qemu_loadvm_section_part_end(f, mis);
if (ret < 0) {
goto out;
}
break;
case QEMU_VM_COMMAND:
ret = loadvm_process_command(f);
trace_qemu_loadvm_state_section_command(ret);
if ((ret < 0) || (ret == LOADVM_QUIT)) {
goto out;
}
break;
case QEMU_VM_EOF:
/* This is the end of migration */
goto out;
default:
error_report("Unknown savevm section type %d", section_type);
ret = -EINVAL;
goto out;
}
}
out:
if (ret < 0) {
qemu_file_set_error(f, ret);
/* Cancel bitmaps incoming regardless of recovery */
dirty_bitmap_mig_cancel_incoming();
/*
* If we are during an active postcopy, then we pause instead
* of bail out to at least keep the VM's dirty data. Note
* that POSTCOPY_INCOMING_LISTENING stage is still not enough,
* during which we're still receiving device states and we
* still haven't yet started the VM on destination.
*
* Only RAM postcopy supports recovery. Still, if RAM postcopy is
* enabled, canceled bitmaps postcopy will not affect RAM postcopy
* recovering.
*/
if (postcopy_state_get() == POSTCOPY_INCOMING_RUNNING &&
migrate_postcopy_ram() && postcopy_pause_incoming(mis)) {
/* Reset f to point to the newly created channel */
f = mis->from_src_file;
goto retry;
}
}
return ret;
}
int qemu_loadvm_state(QEMUFile *f)
{
MigrationIncomingState *mis = migration_incoming_get_current();
Error *local_err = NULL;
int ret;
if (qemu_savevm_state_blocked(&local_err)) {
error_report_err(local_err);
return -EINVAL;
}
ret = qemu_loadvm_state_header(f);
if (ret) {
return ret;
}
if (qemu_loadvm_state_setup(f) != 0) {
return -EINVAL;
}
cpu_synchronize_all_pre_loadvm();
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);
}
}
qemu_loadvm_state_cleanup();
cpu_synchronize_all_post_init();
return ret;
}
int qemu_load_device_state(QEMUFile *f)
{
MigrationIncomingState *mis = migration_incoming_get_current();
int ret;
/* Load QEMU_VM_SECTION_FULL section */
ret = qemu_loadvm_state_main(f, mis);
if (ret < 0) {
error_report("Failed to load device state: %d", ret);
return ret;
}
cpu_synchronize_all_post_init();
return 0;
}
int save_snapshot(const char *name, Error **errp)
{
BlockDriverState *bs, *bs1;
QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1;
int ret = -1, ret2;
QEMUFile *f;
int saved_vm_running;
uint64_t vm_state_size;
qemu_timeval tv;
struct tm tm;
AioContext *aio_context;
if (migration_is_blocked(errp)) {
return ret;
}
if (!replay_can_snapshot()) {
error_setg(errp, "Record/replay does not allow making snapshot "
"right now. Try once more later.");
return ret;
}
if (!bdrv_all_can_snapshot(&bs)) {
error_setg(errp, "Device '%s' is writable but does not support "
"snapshots", bdrv_get_device_or_node_name(bs));
return ret;
}
/* Delete old snapshots of the same name */
if (name) {
ret = bdrv_all_delete_snapshot(name, &bs1, errp);
if (ret < 0) {
error_prepend(errp, "Error while deleting snapshot on device "
"'%s': ", bdrv_get_device_or_node_name(bs1));
return ret;
}
}
bs = bdrv_all_find_vmstate_bs();
if (bs == NULL) {
error_setg(errp, "No block device can accept snapshots");
return ret;
}
aio_context = bdrv_get_aio_context(bs);
saved_vm_running = runstate_is_running();
ret = global_state_store();
if (ret) {
error_setg(errp, "Error saving global state");
return ret;
}
vm_stop(RUN_STATE_SAVE_VM);
bdrv_drain_all_begin();
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 (replay_mode != REPLAY_MODE_NONE) {
sn->icount = replay_get_current_icount();
} else {
sn->icount = -1ULL;
}
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) {
error_setg(errp, "Could not open VM state file");
goto the_end;
}
ret = qemu_savevm_state(f, errp);
vm_state_size = qemu_ftell(f);
ret2 = qemu_fclose(f);
if (ret < 0) {
goto the_end;
}
if (ret2 < 0) {
ret = ret2;
goto the_end;
}
/* The bdrv_all_create_snapshot() call that follows acquires the AioContext
* for itself. BDRV_POLL_WHILE() does not support nested locking because
* it only releases the lock once. Therefore synchronous I/O will deadlock
* unless we release the AioContext before bdrv_all_create_snapshot().
*/
aio_context_release(aio_context);
aio_context = NULL;
ret = bdrv_all_create_snapshot(sn, bs, vm_state_size, &bs);
if (ret < 0) {
error_setg(errp, "Error while creating snapshot on '%s'",
bdrv_get_device_or_node_name(bs));
goto the_end;
}
ret = 0;
the_end:
if (aio_context) {
aio_context_release(aio_context);
}
bdrv_drain_all_end();
if (saved_vm_running) {
vm_start();
}
return ret;
}
void qmp_xen_save_devices_state(const char *filename, bool has_live, bool live,
Error **errp)
{
QEMUFile *f;
QIOChannelFile *ioc;
int saved_vm_running;
int ret;
if (!has_live) {
/* live default to true so old version of Xen tool stack can have a
* successful live migration */
live = true;
}
saved_vm_running = runstate_is_running();
vm_stop(RUN_STATE_SAVE_VM);
global_state_store_running();
ioc = qio_channel_file_new_path(filename, O_WRONLY | O_CREAT | O_TRUNC,
0660, errp);
if (!ioc) {
goto the_end;
}
qio_channel_set_name(QIO_CHANNEL(ioc), "migration-xen-save-state");
f = qemu_fopen_channel_output(QIO_CHANNEL(ioc));
object_unref(OBJECT(ioc));
ret = qemu_save_device_state(f);
if (ret < 0 || qemu_fclose(f) < 0) {
error_setg(errp, QERR_IO_ERROR);
} else {
/* libxl calls the QMP command "stop" before calling
* "xen-save-devices-state" and in case of migration failure, libxl
* would call "cont".
* So call bdrv_inactivate_all (release locks) here to let the other
* side of the migration take control of the images.
*/
if (live && !saved_vm_running) {
ret = bdrv_inactivate_all();
if (ret) {
error_setg(errp, "%s: bdrv_inactivate_all() failed (%d)",
__func__, ret);
}
}
}
the_end:
if (saved_vm_running) {
vm_start();
}
}
void qmp_xen_load_devices_state(const char *filename, Error **errp)
{
QEMUFile *f;
QIOChannelFile *ioc;
int ret;
/* Guest must be paused before loading the device state; the RAM state
* will already have been loaded by xc
*/
if (runstate_is_running()) {
error_setg(errp, "Cannot update device state while vm is running");
return;
}
vm_stop(RUN_STATE_RESTORE_VM);
ioc = qio_channel_file_new_path(filename, O_RDONLY | O_BINARY, 0, errp);
if (!ioc) {
return;
}
qio_channel_set_name(QIO_CHANNEL(ioc), "migration-xen-load-state");
f = qemu_fopen_channel_input(QIO_CHANNEL(ioc));
object_unref(OBJECT(ioc));
ret = qemu_loadvm_state(f);
qemu_fclose(f);
if (ret < 0) {
error_setg(errp, QERR_IO_ERROR);
}
migration_incoming_state_destroy();
}
int load_snapshot(const char *name, Error **errp)
{
BlockDriverState *bs, *bs_vm_state;
QEMUSnapshotInfo sn;
QEMUFile *f;
int ret;
AioContext *aio_context;
MigrationIncomingState *mis = migration_incoming_get_current();
if (!bdrv_all_can_snapshot(&bs)) {
error_setg(errp,
"Device '%s' is writable but does not support snapshots",
bdrv_get_device_or_node_name(bs));
return -ENOTSUP;
}
ret = bdrv_all_find_snapshot(name, &bs);
if (ret < 0) {
error_setg(errp,
"Device '%s' does not have the requested snapshot '%s'",
bdrv_get_device_or_node_name(bs), name);
return ret;
}
bs_vm_state = bdrv_all_find_vmstate_bs();
if (!bs_vm_state) {
error_setg(errp, "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_setg(errp, "This is a disk-only snapshot. Revert to it "
" offline using qemu-img");
return -EINVAL;
}
/*
* Flush the record/replay queue. Now the VM state is going
* to change. Therefore we don't need to preserve its consistency
*/
replay_flush_events();
/* Flush all IO requests so they don't interfere with the new state. */
bdrv_drain_all_begin();
ret = bdrv_all_goto_snapshot(name, &bs, errp);
if (ret < 0) {
error_prepend(errp, "Could not load snapshot '%s' on '%s': ",
name, bdrv_get_device_or_node_name(bs));
goto err_drain;
}
/* restore the VM state */
f = qemu_fopen_bdrv(bs_vm_state, 0);
if (!f) {
error_setg(errp, "Could not open VM state file");
ret = -EINVAL;
goto err_drain;
}
qemu_system_reset(SHUTDOWN_CAUSE_NONE);
mis->from_src_file = f;
aio_context_acquire(aio_context);
ret = qemu_loadvm_state(f);
migration_incoming_state_destroy();
aio_context_release(aio_context);
bdrv_drain_all_end();
if (ret < 0) {
error_setg(errp, "Error %d while loading VM state", ret);
return ret;
}
return 0;
err_drain:
bdrv_drain_all_end();
return ret;
}
void vmstate_register_ram(MemoryRegion *mr, DeviceState *dev)
{
qemu_ram_set_idstr(mr->ram_block,
memory_region_name(mr), dev);
qemu_ram_set_migratable(mr->ram_block);
}
void vmstate_unregister_ram(MemoryRegion *mr, DeviceState *dev)
{
qemu_ram_unset_idstr(mr->ram_block);
qemu_ram_unset_migratable(mr->ram_block);
}
void vmstate_register_ram_global(MemoryRegion *mr)
{
vmstate_register_ram(mr, NULL);
}
bool vmstate_check_only_migratable(const VMStateDescription *vmsd)
{
/* check needed if --only-migratable is specified */
if (!only_migratable) {
return true;
}
return !(vmsd && vmsd->unmigratable);
}
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