diff options
| -rw-r--r-- | migration/migration.c | 9 | ||||
| -rw-r--r-- | migration/migration.h | 7 | ||||
| -rw-r--r-- | migration/postcopy-ram.c | 10 |
3 files changed, 24 insertions, 2 deletions
diff --git a/migration/migration.c b/migration/migration.c index 37fc4fb3e2..bda4789193 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -4388,6 +4388,15 @@ void migrate_fd_connect(MigrationState *s, Error *error_in) } } + /* + * This needs to be done before resuming a postcopy. Note: for newer + * QEMUs we will delay the channel creation until postcopy_start(), to + * avoid disorder of channel creations. + */ + if (migrate_postcopy_preempt() && s->preempt_pre_7_2) { + postcopy_preempt_setup(s); + } + if (resume) { /* Wakeup the main migration thread to do the recovery */ migrate_set_state(&s->state, MIGRATION_STATUS_POSTCOPY_PAUSED, diff --git a/migration/migration.h b/migration/migration.h index 67baba2184..310ae8901b 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -384,12 +384,19 @@ struct MigrationState { * - postcopy preempt src QEMU instance will generate an EOS message at * the end of migration to shut the preempt channel on dest side. * + * - postcopy preempt channel will be created at the setup phase on src + QEMU. + * * When clear: * * - postcopy preempt src QEMU instance will _not_ generate an EOS * message at the end of migration, the dest qemu will shutdown the * channel itself. * + * - postcopy preempt channel will be created at the switching phase + * from precopy -> postcopy (to avoid race condtion of misordered + * creation of channels). + * * NOTE: See message-id <ZBoShWArKDPpX/D7@work-vm> on qemu-devel * mailing list for more information on the possible race. Everyone * should probably just keep this value untouched after set by the diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index 263bab75ec..93f39f8e06 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -1630,8 +1630,14 @@ int postcopy_preempt_establish_channel(MigrationState *s) return 0; } - /* Kick off async task to establish preempt channel */ - postcopy_preempt_setup(s); + /* + * Kick off async task to establish preempt channel. Only do so with + * 8.0+ machines, because 7.1/7.2 require the channel to be created in + * setup phase of migration (even if racy in an unreliable network). + */ + if (!s->preempt_pre_7_2) { + postcopy_preempt_setup(s); + } /* * We need the postcopy preempt channel to be established before |