From: "Maciej S. Szmigiero" <[email protected]>
This QEMU_VM_COMMAND sub-command and its switchover_start SaveVMHandler is
used to mark the switchover point in main migration stream.
It can be used to inform the destination that all pre-switchover main
migration stream data has been sent/received so it can start to process
post-switchover data that it might have received via other migration
channels like the multifd ones.
Add also the relevant MigrationState bit stream compatibility property and
its hw_compat entry.
Signed-off-by: Maciej S. Szmigiero <[email protected]>
---
hw/core/machine.c | 1 +
include/migration/client-options.h | 4 +++
include/migration/register.h | 12 +++++++++
migration/colo.c | 3 +++
migration/migration-hmp-cmds.c | 2 ++
migration/migration.c | 3 +++
migration/migration.h | 2 ++
migration/options.c | 9 +++++++
migration/savevm.c | 39 ++++++++++++++++++++++++++++++
migration/savevm.h | 1 +
migration/trace-events | 1 +
scripts/analyze-migration.py | 11 +++++++++
12 files changed, 88 insertions(+)
diff --git a/hw/core/machine.c b/hw/core/machine.c
index a35c4a8faecb..ed8d39fd769f 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -38,6 +38,7 @@
GlobalProperty hw_compat_9_1[] = {
{ TYPE_PCI_DEVICE, "x-pcie-ext-tag", "false" },
+ { "migration", "send-switchover-start", "off"},
};
const size_t hw_compat_9_1_len = G_N_ELEMENTS(hw_compat_9_1);
diff --git a/include/migration/client-options.h b/include/migration/client-options.h
index 59f4b55cf4f7..289c9d776221 100644
--- a/include/migration/client-options.h
+++ b/include/migration/client-options.h
@@ -10,6 +10,10 @@
#ifndef QEMU_MIGRATION_CLIENT_OPTIONS_H
#define QEMU_MIGRATION_CLIENT_OPTIONS_H
+
+/* properties */
+bool migrate_send_switchover_start(void);
+
/* capabilities */
bool migrate_background_snapshot(void);
diff --git a/include/migration/register.h b/include/migration/register.h
index 0b0292738320..ff0faf5f68c8 100644
--- a/include/migration/register.h
+++ b/include/migration/register.h
@@ -279,6 +279,18 @@ typedef struct SaveVMHandlers {
* otherwise
*/
bool (*switchover_ack_needed)(void *opaque);
+
+ /**
+ * @switchover_start
+ *
+ * Notifies that the switchover has started. Called only on
+ * the destination.
+ *
+ * @opaque: data pointer passed to register_savevm_live()
+ *
+ * Returns zero to indicate success and negative for error
+ */
+ int (*switchover_start)(void *opaque);
+
/* Note: device state is saved into buffer */
ret = qemu_save_device_state(fb);
diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
index 20d1a6e21948..59d0c48a3e0d 100644
--- a/migration/migration-hmp-cmds.c
+++ b/migration/migration-hmp-cmds.c
@@ -46,6 +46,8 @@ static void migration_global_dump(Monitor *mon)
ms->send_configuration ? "on" : "off");
monitor_printf(mon, "send-section-footer: %s\n",
ms->send_section_footer ? "on" : "off");
+ monitor_printf(mon, "send-switchover-start: %s\n",
+ ms->send_switchover_start ? "on" : "off");
monitor_printf(mon, "clear-bitmap-shift: %u\n",
ms->clear_bitmap_shift);
}
diff --git a/migration/migration.c b/migration/migration.c
index 8c5bd0a75c85..2e9d6d5087d7 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2543,6 +2543,8 @@ static int postcopy_start(MigrationState *ms, Error
**errp)
}
restart_block = true;
+ qemu_savevm_maybe_send_switchover_start(ms->to_dst_file);
+
/*
* Cause any non-postcopiable, but iterative devices to
* send out their final data.
@@ -2742,6 +2744,7 @@ static int migration_completion_precopy(MigrationState *s,
*/
s->block_inactive = !migrate_colo();
migration_rate_set(RATE_LIMIT_DISABLED);
+ qemu_savevm_maybe_send_switchover_start(s->to_dst_file);
ret = qemu_savevm_state_complete_precopy(s->to_dst_file, false,
s->block_inactive);
out_unlock:
diff --git a/migration/migration.h b/migration/migration.h
index 0956e9274b2c..2a18349cfec2 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -403,6 +403,8 @@ struct MigrationState {
bool send_configuration;
/* Whether we send section footer during migration */
bool send_section_footer;
+ /* Whether we send switchover start notification during migration */
+ bool send_switchover_start;
/* Needed by postcopy-pause state */
QemuSemaphore postcopy_pause_sem;
diff --git a/migration/options.c b/migration/options.c
index ad8d6989a807..f916c8ed4e09 100644
--- a/migration/options.c
+++ b/migration/options.c
@@ -92,6 +92,8 @@ Property migration_properties[] = {
send_configuration, true),
DEFINE_PROP_BOOL("send-section-footer", MigrationState,
send_section_footer, true),
+ DEFINE_PROP_BOOL("send-switchover-start", MigrationState,
+ send_switchover_start, true),
DEFINE_PROP_BOOL("multifd-flush-after-each-section", MigrationState,
multifd_flush_after_each_section, false),
DEFINE_PROP_UINT8("x-clear-bitmap-shift", MigrationState,
@@ -206,6 +208,13 @@ bool migrate_auto_converge(void)
return s->capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
}
+bool migrate_send_switchover_start(void)
+{
+ MigrationState *s = migrate_get_current();
+
+ return s->send_switchover_start;
+}
+
bool migrate_background_snapshot(void)
{
MigrationState *s = migrate_get_current();
diff --git a/migration/savevm.c b/migration/savevm.c
index f4e4876f7202..a254c38edcca 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -90,6 +90,7 @@ enum qemu_vm_cmd {
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_SWITCHOVER_START, /* Switchover start notification */
MIG_CMD_MAX
};
@@ -109,6 +110,7 @@ static struct mig_cmd_args {
[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_SWITCHOVER_START] = { .len = 0, .name = "SWITCHOVER_START" },
[MIG_CMD_MAX] = { .len = -1, .name = "MAX" },
};
@@ -1201,6 +1203,19 @@ void qemu_savevm_send_recv_bitmap(QEMUFile *f, char *block_name)
qemu_savevm_command_send(f, MIG_CMD_RECV_BITMAP, len + 1, (uint8_t *)buf);
}
+static void qemu_savevm_send_switchover_start(QEMUFile *f)
+{
+ trace_savevm_send_switchover_start();
+ qemu_savevm_command_send(f, MIG_CMD_SWITCHOVER_START, 0, NULL);
+}
+
+void qemu_savevm_maybe_send_switchover_start(QEMUFile *f)
+{
+ if (migrate_send_switchover_start()) {
+ qemu_savevm_send_switchover_start(f);
+ }
+}
+
bool qemu_savevm_state_blocked(Error **errp)
{
SaveStateEntry *se;
@@ -1713,6 +1728,7 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp)
ret = qemu_file_get_error(f);
if (ret == 0) {
+ qemu_savevm_maybe_send_switchover_start(f);
qemu_savevm_state_complete_precopy(f, false, false);
ret = qemu_file_get_error(f);
}
@@ -2413,6 +2429,26 @@ static int
loadvm_process_enable_colo(MigrationIncomingState *mis)
return ret;
}
+static int loadvm_postcopy_handle_switchover_start(void)
+{
+ SaveStateEntry *se;
+
+ QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+ int ret;
+
+ if (!se->ops || !se->ops->switchover_start) {
+ continue;
+ }
+
+ ret = se->ops->switchover_start(se->opaque);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
/*
* Process an incoming 'QEMU_VM_COMMAND'
* 0 just a normal return
@@ -2511,6 +2547,9 @@ static int loadvm_process_command(QEMUFile *f)
case MIG_CMD_ENABLE_COLO:
return loadvm_process_enable_colo(mis);
+
+ case MIG_CMD_SWITCHOVER_START:
+ return loadvm_postcopy_handle_switchover_start();
}
return 0;
diff --git a/migration/savevm.h b/migration/savevm.h
index 9ec96a995c93..4d402723bc3c 100644
--- a/migration/savevm.h
+++ b/migration/savevm.h
@@ -53,6 +53,7 @@ void qemu_savevm_send_postcopy_listen(QEMUFile *f);
void qemu_savevm_send_postcopy_run(QEMUFile *f);
void qemu_savevm_send_postcopy_resume(QEMUFile *f);
void qemu_savevm_send_recv_bitmap(QEMUFile *f, char *block_name);
+void qemu_savevm_maybe_send_switchover_start(QEMUFile *f);
void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name,
uint16_t len,
diff --git a/migration/trace-events b/migration/trace-events
index bb0e0cc6dcfe..551f5af0740f 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -39,6 +39,7 @@ savevm_send_postcopy_run(void) ""
savevm_send_postcopy_resume(void) ""
savevm_send_colo_enable(void) ""
savevm_send_recv_bitmap(char *name) "%s"
+savevm_send_switchover_start(void) ""
savevm_state_setup(void) ""
savevm_state_resume_prepare(void) ""
savevm_state_header(void) ""
diff --git a/scripts/analyze-migration.py b/scripts/analyze-migration.py
index 8a254a5b6a2e..a4d4042584c0 100755
--- a/scripts/analyze-migration.py
+++ b/scripts/analyze-migration.py
@@ -564,7 +564,9 @@ class MigrationDump(object):
QEMU_VM_SUBSECTION = 0x05
QEMU_VM_VMDESCRIPTION = 0x06
QEMU_VM_CONFIGURATION = 0x07
+ QEMU_VM_COMMAND = 0x08
QEMU_VM_SECTION_FOOTER= 0x7e
+ QEMU_MIG_CMD_SWITCHOVER_START = 0x0b
def __init__(self, filename):
self.section_classes = {
@@ -626,6 +628,15 @@ def read(self, desc_only = False, dump_memory = False,
write_memory = False):
elif section_type == self.QEMU_VM_SECTION_PART or section_type ==
self.QEMU_VM_SECTION_END:
section_id = file.read32()
self.sections[section_id].read()
+ elif section_type == self.QEMU_VM_COMMAND:
+ command_type = file.read16()
+ command_data_len = file.read16()
+ if command_type != self.QEMU_MIG_CMD_SWITCHOVER_START:
+ raise Exception("Unknown QEMU_VM_COMMAND: %x" %
+ (command_type))
+ if command_data_len != 0:
+ raise Exception("Invalid SWITCHOVER_START length: %x" %
+ (command_data_len))
elif section_type == self.QEMU_VM_SECTION_FOOTER:
read_section_id = file.read32()
if read_section_id != section_id:
