Re: [Qemu-devel] [PATCH 04/11] global_state: Make section optional

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

* Juan Quintela (quintela@redhat.com) wrote:
> This section would be sent:
> 
> a- for all new machine types
> b- for old achine types if section state is different form {running,paused}
>    that were the only giving us troubles.
> 
> So, in new qemus: it is alwasy there.  In old qemus: they are only
> there if it an error has happened, basically stoping on target.

Possibly for a different patch in the series; but I'm worried about
at least two of the other states:
   SAVE_VM - I think this means that savevm/loadvm is broken?
   SUSPENDED - what happens to a migrate of a suspended VM?

Dave

> Signed-off-by: Juan Quintela <quintela@redhat.com>
> ---
>  hw/i386/pc_piix.c             |  1 +
>  hw/i386/pc_q35.c              |  1 +
>  include/migration/migration.h |  1 +
>  migration/migration.c         | 30 +++++++++++++++++++++++++++++-
>  4 files changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index e142f75..735fb22 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -307,6 +307,7 @@ static void pc_init1(MachineState *machine)
>  static void pc_compat_2_3(MachineState *machine)
>  {
>      savevm_skip_section_footers();
> +    global_state_set_optional();
>  }
> 
>  static void pc_compat_2_2(MachineState *machine)
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index b68263d..0523ecc 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -291,6 +291,7 @@ static void pc_q35_init(MachineState *machine)
>  static void pc_compat_2_3(MachineState *machine)
>  {
>      savevm_skip_section_footers();
> +    global_state_set_optional();
>  }
> 
>  static void pc_compat_2_2(MachineState *machine)
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index 1280193..bb53d93 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -198,4 +198,5 @@ 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);
> +void global_state_set_optional(void);
>  #endif
> diff --git a/migration/migration.c b/migration/migration.c
> index 01bb90d..f1ecf76 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -99,6 +99,7 @@ void migration_incoming_state_destroy(void)
> 
> 
>  typedef struct {
> +    bool optional;
>      int32_t size;
>      uint8_t runstate[100];
>  } GlobalState;
> @@ -119,6 +120,33 @@ static char *global_state_get_runstate(void)
>      return (char *)global_state.runstate;
>  }
> 
> +void global_state_set_optional(void)
> +{
> +    global_state.optional = true;
> +}
> +
> +static bool global_state_needed(void *opaque)
> +{
> +    GlobalState *s = opaque;
> +    char *runstate = (char *)s->runstate;
> +
> +    /* If it is not optional, it is mandatory */
> +
> +    if (s->optional == false) {
> +        return true;
> +    }
> +
> +    /* If state is running or paused, it is not needed */
> +
> +    if (strcmp(runstate, "running") == 0 ||
> +        strcmp(runstate, "paused") == 0) {
> +        return false;
> +    }
> +
> +    /* for any other state it is needed */
> +    return true;
> +}
> +
>  static int global_state_post_load(void *opaque, int version_id)
>  {
>      GlobalState *s = opaque;
> @@ -149,7 +177,6 @@ static void global_state_pre_save(void *opaque)
>      GlobalState *s = opaque;
> 
>      s->size = strlen((char *)s->runstate) + 1;
> -    printf("saved state: %s\n", s->runstate);
>  }
> 
>  static const VMStateDescription vmstate_globalstate = {
> @@ -158,6 +185,7 @@ static const VMStateDescription vmstate_globalstate = {
>      .minimum_version_id = 1,
>      .post_load = global_state_post_load,
>      .pre_save = global_state_pre_save,
> +    .needed = global_state_needed,
>      .fields = (VMStateField[]) {
>          VMSTATE_INT32(size, GlobalState),
>          VMSTATE_BUFFER(runstate, GlobalState),
> -- 
> 2.4.3
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK