Re: [Qemu-devel] [PATCH v4 3/5] migration: Create load_setup()/cleanup() methods

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Juan Quintela (quintela@redhat.com) wrote:
> We need to do things at load time and at cleanup time.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> 
> --
> 
> Move the printing of the error message so we can print the device
> giving the error.
> Add call to postcopy stuff
> ---
>  include/migration/register.h |  2 ++
>  migration/savevm.c           | 45 +++++++++++++++++++++++++++++++++++++++++++-
>  migration/savevm.h           |  1 +
>  migration/trace-events       |  2 ++
>  4 files changed, 49 insertions(+), 1 deletion(-)
> 
> diff --git a/include/migration/register.h b/include/migration/register.h
> index 938ea2b..a0f1edd 100644
> --- a/include/migration/register.h
> +++ b/include/migration/register.h
> @@ -39,6 +39,8 @@ typedef struct SaveVMHandlers {
>                                uint64_t *non_postcopiable_pending,
>                                uint64_t *postcopiable_pending);
>      LoadStateHandler *load_state;
> +    int (*load_setup)(QEMUFile *f, void *opaque);
> +    int (*load_cleanup)(void *opaque);
>  } SaveVMHandlers;
>  
>  int register_savevm_live(DeviceState *dev,
> diff --git a/migration/savevm.c b/migration/savevm.c
> index fee11c5..fdd15fa 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -1541,7 +1541,7 @@ static void *postcopy_ram_listen_thread(void *opaque)
>       * got a bad migration state).
>       */
>      migration_incoming_state_destroy();
> -
> +    qemu_loadvm_state_cleanup();

Is that order right? It seems wrong to call the cleanup
code after MIS is destroyed.
(The precopy path seems to call mis_destroy at the end of
process_incoming_migration_bh which is much later).

Dave

>      return NULL;
>  }
> @@ -1901,6 +1901,44 @@ qemu_loadvm_section_part_end(QEMUFile *f, MigrationIncomingState *mis)
>      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 && 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);
> +        }
> +    }
> +}
> +
>  static int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis)
>  {
>      uint8_t section_type;
> @@ -1973,6 +2011,10 @@ int qemu_loadvm_state(QEMUFile *f)
>          return -ENOTSUP;
>      }
>  
> +    if (qemu_loadvm_state_setup(f) != 0) {
> +        return -EINVAL;
> +    }
> +
>      if (migrate_get_current()->send_configuration) {
>          if (qemu_get_byte(f) != QEMU_VM_CONFIGURATION) {
>              error_report("Configuration section missing");
> @@ -2036,6 +2078,7 @@ int qemu_loadvm_state(QEMUFile *f)
>          }
>      }
>  
> +    qemu_loadvm_state_cleanup();
>      cpu_synchronize_all_post_init();
>  
>      return ret;
> diff --git a/migration/savevm.h b/migration/savevm.h
> index 6babc62..295c4a1 100644
> --- a/migration/savevm.h
> +++ b/migration/savevm.h
> @@ -53,5 +53,6 @@ void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name,
>                                             uint64_t *length_list);
>  
>  int qemu_loadvm_state(QEMUFile *f);
> +void qemu_loadvm_state_cleanup(void);
>  
>  #endif
> diff --git a/migration/trace-events b/migration/trace-events
> index 9669e94..cb2c4b5 100644
> --- a/migration/trace-events
> +++ b/migration/trace-events
> @@ -7,6 +7,8 @@ qemu_loadvm_state_section_partend(uint32_t section_id) "%u"
>  qemu_loadvm_state_post_main(int ret) "%d"
>  qemu_loadvm_state_section_startfull(uint32_t section_id, const char *idstr, uint32_t instance_id, uint32_t version_id) "%u(%s) %u %u"
>  qemu_savevm_send_packaged(void) ""
> +loadvm_state_setup(void) ""
> +loadvm_state_cleanup(void) ""
>  loadvm_handle_cmd_packaged(unsigned int length) "%u"
>  loadvm_handle_cmd_packaged_main(int ret) "%d"
>  loadvm_handle_cmd_packaged_received(int ret) "%d"
> -- 
> 2.9.4
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK