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qemu/migration/savevm.c
Daniel P. Berrangé 0f0d83a456 migration: introduce snapshot-{save, load, delete} QMP commands 
savevm, loadvm and delvm are some of the few HMP commands that have never
been converted to use QMP. The reasons for the lack of conversion are
that they blocked execution of the event thread, and the semantics
around choice of disks were ill-defined.

Despite this downside, however, libvirt and applications using libvirt
have used these commands for as long as QMP has existed, via the
"human-monitor-command" passthrough command. IOW, while it is clearly
desirable to be able to fix the problems, they are not a blocker to
all real world usage.

Meanwhile there is a need for other features which involve adding new
parameters to the commands. This is possible with HMP passthrough, but
it provides no reliable way for apps to introspect features, so using
QAPI modelling is highly desirable.

This patch thus introduces new snapshot-{load,save,delete} commands to
QMP that are intended to replace the old HMP counterparts. The new
commands are given different names, because they will be using the new
QEMU job framework and thus will have diverging behaviour from the HMP
originals. It would thus be misleading to keep the same name.

While this design uses the generic job framework, the current impl is
still blocking. The intention that the blocking problem is fixed later.
None the less applications using these new commands should assume that
they are asynchronous and thus wait for the job status change event to
indicate completion.

In addition to using the job framework, the new commands require the
caller to be explicit about all the block device nodes used in the
snapshot operations, with no built-in default heuristics in use.

Note that the existing "query-named-block-nodes" can be used to query
what snapshots currently exist for block nodes.

Acked-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20210204124834.774401-13-berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  dgilbert: removed tests for now, the output ordering isn't
deterministic
2021-02-08 11:19:52 +00:00

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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/clone-visitor.h"
#include "qapi/qapi-builtin-visit.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"
#include "qemu/yank.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_post_save(void *opaque)
{
SaveState *state = opaque;
g_free(state->capabilities);
state->capabilities = NULL;
state->caps_count = 0;
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;
int ret = 0;
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);
ret = -EINVAL;
goto out;
}
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());
ret = -EINVAL;
goto out;
}
if (!configuration_validate_capabilities(state)) {
ret = -EINVAL;
goto out;
}
out:
g_free((void *)state->name);
state->name = NULL;
state->len = 0;
g_free(state->capabilities);
state->capabilities = NULL;
state->caps_count = 0;
return ret;
}
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,
.post_save = configuration_post_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_non_migratable_list(strList **reasons)
{
SaveStateEntry *se;
QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
if (se->vmsd && se->vmsd->unmigratable) {
QAPI_LIST_PREPEND(*reasons,
g_strdup_printf("non-migratable device: %s",
se->idstr));
}
}
}
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;
}
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;
}
bool save_snapshot(const char *name, bool overwrite, const char *vmstate,
bool has_devices, strList *devices, Error **errp)
{
BlockDriverState *bs;
QEMUSnapshotInfo sn1, *sn = &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 false;
}
if (!replay_can_snapshot()) {
error_setg(errp, "Record/replay does not allow making snapshot "
"right now. Try once more later.");
return false;
}
if (!bdrv_all_can_snapshot(has_devices, devices, errp)) {
return false;
}
/* Delete old snapshots of the same name */
if (name) {
if (overwrite) {
if (bdrv_all_delete_snapshot(name, has_devices,
devices, errp) < 0) {
return false;
}
} else {
ret2 = bdrv_all_has_snapshot(name, has_devices, devices, errp);
if (ret2 < 0) {
return false;
}
if (ret2 == 1) {
error_setg(errp,
"Snapshot '%s' already exists in one or more devices",
name);
return false;
}
}
}
bs = bdrv_all_find_vmstate_bs(vmstate, has_devices, devices, errp);
if (bs == NULL) {
return false;
}
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 false;
}
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) {
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,
has_devices, devices, errp);
if (ret < 0) {
bdrv_all_delete_snapshot(sn->name, has_devices, devices, NULL);
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 == 0;
}
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();
}
bool load_snapshot(const char *name, const char *vmstate,
bool has_devices, strList *devices, Error **errp)
{
BlockDriverState *bs_vm_state;
QEMUSnapshotInfo sn;
QEMUFile *f;
int ret;
AioContext *aio_context;
MigrationIncomingState *mis = migration_incoming_get_current();
if (!bdrv_all_can_snapshot(has_devices, devices, errp)) {
return false;
}
ret = bdrv_all_has_snapshot(name, has_devices, devices, errp);
if (ret < 0) {
return false;
}
if (ret == 0) {
error_setg(errp, "Snapshot '%s' does not exist in one or more devices",
name);
return false;
}
bs_vm_state = bdrv_all_find_vmstate_bs(vmstate, has_devices, devices, errp);
if (!bs_vm_state) {
return false;
}
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 false;
} else if (sn.vm_state_size == 0) {
error_setg(errp, "This is a disk-only snapshot. Revert to it "
" offline using qemu-img");
return false;
}
/*
* 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, has_devices, devices, errp);
if (ret < 0) {
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");
goto err_drain;
}
qemu_system_reset(SHUTDOWN_CAUSE_NONE);
mis->from_src_file = f;
if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) {
ret = -EINVAL;
goto err_drain;
}
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 false;
}
return true;
err_drain:
bdrv_drain_all_end();
return false;
}
bool delete_snapshot(const char *name, bool has_devices,
strList *devices, Error **errp)
{
if (!bdrv_all_can_snapshot(has_devices, devices, errp)) {
return false;
}
if (bdrv_all_delete_snapshot(name, has_devices, devices, errp) < 0) {
return false;
}
return true;
}
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);
}
typedef struct SnapshotJob {
Job common;
char *tag;
char *vmstate;
strList *devices;
Coroutine *co;
Error **errp;
bool ret;
} SnapshotJob;
static void qmp_snapshot_job_free(SnapshotJob *s)
{
g_free(s->tag);
g_free(s->vmstate);
qapi_free_strList(s->devices);
}
static void snapshot_load_job_bh(void *opaque)
{
Job *job = opaque;
SnapshotJob *s = container_of(job, SnapshotJob, common);
int orig_vm_running;
job_progress_set_remaining(&s->common, 1);
orig_vm_running = runstate_is_running();
vm_stop(RUN_STATE_RESTORE_VM);
s->ret = load_snapshot(s->tag, s->vmstate, true, s->devices, s->errp);
if (s->ret && orig_vm_running) {
vm_start();
}
job_progress_update(&s->common, 1);
qmp_snapshot_job_free(s);
aio_co_wake(s->co);
}
static void snapshot_save_job_bh(void *opaque)
{
Job *job = opaque;
SnapshotJob *s = container_of(job, SnapshotJob, common);
job_progress_set_remaining(&s->common, 1);
s->ret = save_snapshot(s->tag, false, s->vmstate,
true, s->devices, s->errp);
job_progress_update(&s->common, 1);
qmp_snapshot_job_free(s);
aio_co_wake(s->co);
}
static void snapshot_delete_job_bh(void *opaque)
{
Job *job = opaque;
SnapshotJob *s = container_of(job, SnapshotJob, common);
job_progress_set_remaining(&s->common, 1);
s->ret = delete_snapshot(s->tag, true, s->devices, s->errp);
job_progress_update(&s->common, 1);
qmp_snapshot_job_free(s);
aio_co_wake(s->co);
}
static int coroutine_fn snapshot_save_job_run(Job *job, Error **errp)
{
SnapshotJob *s = container_of(job, SnapshotJob, common);
s->errp = errp;
s->co = qemu_coroutine_self();
aio_bh_schedule_oneshot(qemu_get_aio_context(),
snapshot_save_job_bh, job);
qemu_coroutine_yield();
return s->ret ? 0 : -1;
}
static int coroutine_fn snapshot_load_job_run(Job *job, Error **errp)
{
SnapshotJob *s = container_of(job, SnapshotJob, common);
s->errp = errp;
s->co = qemu_coroutine_self();
aio_bh_schedule_oneshot(qemu_get_aio_context(),
snapshot_load_job_bh, job);
qemu_coroutine_yield();
return s->ret ? 0 : -1;
}
static int coroutine_fn snapshot_delete_job_run(Job *job, Error **errp)
{
SnapshotJob *s = container_of(job, SnapshotJob, common);
s->errp = errp;
s->co = qemu_coroutine_self();
aio_bh_schedule_oneshot(qemu_get_aio_context(),
snapshot_delete_job_bh, job);
qemu_coroutine_yield();
return s->ret ? 0 : -1;
}
static const JobDriver snapshot_load_job_driver = {
.instance_size = sizeof(SnapshotJob),
.job_type = JOB_TYPE_SNAPSHOT_LOAD,
.run = snapshot_load_job_run,
};
static const JobDriver snapshot_save_job_driver = {
.instance_size = sizeof(SnapshotJob),
.job_type = JOB_TYPE_SNAPSHOT_SAVE,
.run = snapshot_save_job_run,
};
static const JobDriver snapshot_delete_job_driver = {
.instance_size = sizeof(SnapshotJob),
.job_type = JOB_TYPE_SNAPSHOT_DELETE,
.run = snapshot_delete_job_run,
};
void qmp_snapshot_save(const char *job_id,
const char *tag,
const char *vmstate,
strList *devices,
Error **errp)
{
SnapshotJob *s;
s = job_create(job_id, &snapshot_save_job_driver, NULL,
qemu_get_aio_context(), JOB_MANUAL_DISMISS,
NULL, NULL, errp);
if (!s) {
return;
}
s->tag = g_strdup(tag);
s->vmstate = g_strdup(vmstate);
s->devices = QAPI_CLONE(strList, devices);
job_start(&s->common);
}
void qmp_snapshot_load(const char *job_id,
const char *tag,
const char *vmstate,
strList *devices,
Error **errp)
{
SnapshotJob *s;
s = job_create(job_id, &snapshot_load_job_driver, NULL,
qemu_get_aio_context(), JOB_MANUAL_DISMISS,
NULL, NULL, errp);
if (!s) {
return;
}
s->tag = g_strdup(tag);
s->vmstate = g_strdup(vmstate);
s->devices = QAPI_CLONE(strList, devices);
job_start(&s->common);
}
void qmp_snapshot_delete(const char *job_id,
const char *tag,
strList *devices,
Error **errp)
{
SnapshotJob *s;
s = job_create(job_id, &snapshot_delete_job_driver, NULL,
qemu_get_aio_context(), JOB_MANUAL_DISMISS,
NULL, NULL, errp);
if (!s) {
return;
}
s->tag = g_strdup(tag);
s->devices = QAPI_CLONE(strList, devices);
job_start(&s->common);
}
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