migration: Set migration status early in incoming side

We are sending a migration event of MIGRATION_STATUS_SETUP at
qemu_start_incoming_migration but never actually setting the state.

This creates a window between qmp_migrate_incoming and
process_incoming_migration_co where the migration status is still
MIGRATION_STATUS_NONE. Calling query-migrate during this time will
return an empty response even though the incoming migration command
has already been issued.

Commit 7cf1fe6d68 ("migration: Add migration events on target side")
has added support to the 'events' capability to the incoming part of
migration, but chose to send the SETUP event without setting the
state. I'm assuming this was a mistake.

This introduces a change in behavior, any QMP client waiting for the
SETUP event will hang, unless it has previously enabled the 'events'
capability. Having the capability enabled is sufficient to continue to
receive the event.

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230712190742.22294-5-farosas@suse.de>
This commit is contained in:
Fabiano Rosas 2023-07-12 16:07:40 -03:00 committed by Juan Quintela
parent 6830e53b4b
commit 4111a732e8

View File

@ -431,13 +431,16 @@ void migrate_add_address(SocketAddress *address)
static void qemu_start_incoming_migration(const char *uri, Error **errp) static void qemu_start_incoming_migration(const char *uri, Error **errp)
{ {
const char *p = NULL; const char *p = NULL;
MigrationIncomingState *mis = migration_incoming_get_current();
/* URI is not suitable for migration? */ /* URI is not suitable for migration? */
if (!migration_channels_and_uri_compatible(uri, errp)) { if (!migration_channels_and_uri_compatible(uri, errp)) {
return; return;
} }
qapi_event_send_migration(MIGRATION_STATUS_SETUP); migrate_set_state(&mis->state, MIGRATION_STATUS_NONE,
MIGRATION_STATUS_SETUP);
if (strstart(uri, "tcp:", &p) || if (strstart(uri, "tcp:", &p) ||
strstart(uri, "unix:", NULL) || strstart(uri, "unix:", NULL) ||
strstart(uri, "vsock:", NULL)) { strstart(uri, "vsock:", NULL)) {
@ -531,7 +534,7 @@ process_incoming_migration_co(void *opaque)
mis->largest_page_size = qemu_ram_pagesize_largest(); mis->largest_page_size = qemu_ram_pagesize_largest();
postcopy_state_set(POSTCOPY_INCOMING_NONE); postcopy_state_set(POSTCOPY_INCOMING_NONE);
migrate_set_state(&mis->state, MIGRATION_STATUS_NONE, migrate_set_state(&mis->state, MIGRATION_STATUS_SETUP,
MIGRATION_STATUS_ACTIVE); MIGRATION_STATUS_ACTIVE);
mis->loadvm_co = qemu_coroutine_self(); mis->loadvm_co = qemu_coroutine_self();