* Christian Borntraeger (borntrae...@de.ibm.com) wrote:
> Am 07.07.2015 um 15:08 schrieb Juan Quintela:
> > This includes a new section that for now just stores the current qemu state.
> >
> > Right now, there are only one way to control what is the state of the
> > target after migration.
> >
> > - If you run the target qemu with -S, it would start stopped.
> > - If you run the target qemu without -S, it would run just after migration
> > finishes.
> >
> > The problem here is what happens if we start the target without -S and
> > there happens one error during migration that puts current state as
> > -EIO. Migration would ends (notice that the error happend doing block
> > IO, network IO, i.e. nothing related with migration), and when
> > migration finish, we would just "continue" running on destination,
> > probably hanging the guest/corruption data, whatever.
> >
> > Signed-off-by: Juan Quintela <quint...@redhat.com>
> > Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
>
> This is bisected to cause a regression on s390.
>
> A guest restarts (booting) after managedsave/start instead of continuing.
>
> Do you have any idea what might be wrong?
I'd add some debug to the pre_save and post_load to see what state value is
being saved/restored.
Also, does that regression happen when doing the save/restore using the
same/latest
git, or is it a load from an older version?
Dave
>
> > ---
> > include/migration/migration.h | 1 +
> > migration/migration.c | 105
> > +++++++++++++++++++++++++++++++++++++++---
> > trace-events | 3 ++
> > vl.c | 1 +
> > 4 files changed, 103 insertions(+), 7 deletions(-)
> >
> > diff --git a/include/migration/migration.h b/include/migration/migration.h
> > index afba233..86df6cc 100644
> > --- a/include/migration/migration.h
> > +++ b/include/migration/migration.h
> > @@ -197,4 +197,5 @@ size_t ram_control_save_page(QEMUFile *f, ram_addr_t
> > block_offset,
> >
> > void ram_mig_init(void);
> > void savevm_skip_section_footers(void);
> > +void register_global_state(void);
> > #endif
> > diff --git a/migration/migration.c b/migration/migration.c
> > index c6ac08a..5e436f7 100644
> > --- a/migration/migration.c
> > +++ b/migration/migration.c
> > @@ -26,6 +26,7 @@
> > #include "qemu/thread.h"
> > #include "qmp-commands.h"
> > #include "trace.h"
> > +#include "qapi/util.h"
> >
> > #define MAX_THROTTLE (32 << 20) /* Migration speed throttling */
> >
> > @@ -97,6 +98,83 @@ void migration_incoming_state_destroy(void)
> > mis_current = NULL;
> > }
> >
> > +
> > +typedef struct {
> > + uint32_t size;
> > + uint8_t runstate[100];
> > +} GlobalState;
> > +
> > +static GlobalState global_state;
> > +
> > +static int global_state_store(void)
> > +{
> > + if (!runstate_store((char *)global_state.runstate,
> > + sizeof(global_state.runstate))) {
> > + error_report("runstate name too big: %s", global_state.runstate);
> > + trace_migrate_state_too_big();
> > + return -EINVAL;
> > + }
> > + return 0;
> > +}
> > +
> > +static char *global_state_get_runstate(void)
> > +{
> > + return (char *)global_state.runstate;
> > +}
> > +
> > +static int global_state_post_load(void *opaque, int version_id)
> > +{
> > + GlobalState *s = opaque;
> > + int ret = 0;
> > + char *runstate = (char *)s->runstate;
> > +
> > + trace_migrate_global_state_post_load(runstate);
> > +
> > + if (strcmp(runstate, "running") != 0) {
> > + Error *local_err = NULL;
> > + int r = qapi_enum_parse(RunState_lookup, runstate, RUN_STATE_MAX,
> > + -1, &local_err);
> > +
> > + if (r == -1) {
> > + if (local_err) {
> > + error_report_err(local_err);
> > + }
> > + return -EINVAL;
> > + }
> > + ret = vm_stop_force_state(r);
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +static void global_state_pre_save(void *opaque)
> > +{
> > + GlobalState *s = opaque;
> > +
> > + trace_migrate_global_state_pre_save((char *)s->runstate);
> > + s->size = strlen((char *)s->runstate) + 1;
> > +}
> > +
> > +static const VMStateDescription vmstate_globalstate = {
> > + .name = "globalstate",
> > + .version_id = 1,
> > + .minimum_version_id = 1,
> > + .post_load = global_state_post_load,
> > + .pre_save = global_state_pre_save,
> > + .fields = (VMStateField[]) {
> > + VMSTATE_UINT32(size, GlobalState),
> > + VMSTATE_BUFFER(runstate, GlobalState),
> > + VMSTATE_END_OF_LIST()
> > + },
> > +};
> > +
> > +void register_global_state(void)
> > +{
> > + /* We would use it independently that we receive it */
> > + strcpy((char *)&global_state.runstate, "");
> > + vmstate_register(NULL, 0, &vmstate_globalstate, &global_state);
> > +}
> > +
> > /*
> > * Called on -incoming with a defer: uri.
> > * The migration can be started later after any parameters have been
> > @@ -164,10 +242,20 @@ static void process_incoming_migration_co(void
> > *opaque)
> > exit(EXIT_FAILURE);
> > }
> >
> > - if (autostart) {
> > + /* runstate == "" means that we haven't received it through the
> > + * wire, so we obey autostart. runstate == runing means that we
> > + * need to run it, we need to make sure that we do it after
> > + * everything else has finished. Every other state change is done
> > + * at the post_load function */
> > +
> > + if (strcmp(global_state_get_runstate(), "running") == 0) {
> > vm_start();
> > - } else {
> > - runstate_set(RUN_STATE_PAUSED);
> > + } else if (strcmp(global_state_get_runstate(), "") == 0) {
> > + if (autostart) {
> > + vm_start();
> > + } else {
> > + runstate_set(RUN_STATE_PAUSED);
> > + }
> > }
> > migrate_decompress_threads_join();
> > }
> > @@ -793,10 +881,13 @@ static void *migration_thread(void *opaque)
> > qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
> > old_vm_running = runstate_is_running();
> >
> > - ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
> > - if (ret >= 0) {
> > - qemu_file_set_rate_limit(s->file, INT64_MAX);
> > - qemu_savevm_state_complete(s->file);
> > + ret = global_state_store();
> > + if (!ret) {
> > + ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
> > + if (ret >= 0) {
> > + qemu_file_set_rate_limit(s->file, INT64_MAX);
> > + qemu_savevm_state_complete(s->file);
> > + }
> > }
> > qemu_mutex_unlock_iothread();
> >
> > diff --git a/trace-events b/trace-events
> > index a38dd2e..c0111d0 100644
> > --- a/trace-events
> > +++ b/trace-events
> > @@ -1403,6 +1403,9 @@ migrate_fd_error(void) ""
> > migrate_fd_cancel(void) ""
> > migrate_pending(uint64_t size, uint64_t max) "pending size %" PRIu64 " max
> > %" PRIu64
> > migrate_transferred(uint64_t tranferred, uint64_t time_spent, double
> > bandwidth, uint64_t size) "transferred %" PRIu64 " time_spent %" PRIu64 "
> > bandwidth %g max_size %" PRId64
> > +migrate_state_too_big(void) ""
> > +migrate_global_state_post_load(const char *state) "loaded state: %s"
> > +migrate_global_state_pre_save(const char *state) "saved state: %s"
> >
> > # migration/rdma.c
> > qemu_rdma_accept_incoming_migration(void) ""
> > diff --git a/vl.c b/vl.c
> > index 19a8737..cfa6133 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -4624,6 +4624,7 @@ int main(int argc, char **argv, char **envp)
> > return 0;
> > }
> >
> > + register_global_state();
> > if (incoming) {
> > Error *local_err = NULL;
> > qemu_start_incoming_migration(incoming, &local_err);
> >
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
