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Date: Wed, 28 Jun 2017 16:13:57 -0300
From: Eduardo Habkost <ehabkost@redhat.com>
Message-ID: <20170628191357.GO12152@localhost.localdomain>
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In-Reply-To: <1498536619-14548-7-git-send-email-peterx@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v6 06/10] migration: move only_migratable
 to MigrationState
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To: Peter Xu <peterx@redhat.com>
Cc: qemu-devel@nongnu.org, Laurent Vivier <lvivier@redhat.com>, Eric Blake <eblake@redhat.com>, Markus Armbruster <armbru@redhat.com>, Juan Quintela <quintela@redhat.com>, "Dr . David Alan Gilbert" <dgilbert@redhat.com>

On Tue, Jun 27, 2017 at 12:10:15PM +0800, Peter Xu wrote:
> One less global variable, and it does only matter with migration.
> 
> We keep the old "--only-migratable" option, but also now we support:
> 
>   -global migration.only-migratable=true
> 
> Currently still keep the old interface.
> 
> Hmm, now vl.c has no way to access migrate_get_current(). Export a
> function for it to setup only_migratable.
> 
> Reviewed-by: Juan Quintela <quintela@redhat.com>
> Signed-off-by: Peter Xu <peterx@redhat.com>
[...]
> +void migration_only_migratable_set(void)
> +{
> +    migrate_get_current()->only_migratable = true;
> +}
> +
[...]
> @@ -3953,7 +3952,13 @@ int main(int argc, char **argv, char **envp)
>                  incoming = optarg;
>                  break;
>              case QEMU_OPTION_only_migratable:
> -                only_migratable = 1;
> +                /*
> +                 * TODO: we can remove this option one day, and we
> +                 * should all use:
> +                 *
> +                 * "-global migration.only-migratable=true"
> +                 */
> +                migration_only_migratable_set();

This triggers a premature call to migrate_get_current():

  $ qemu-system-x86_64 -only-migratable
  qemu-system-x86_64: /home/ehabkost/rh/proj/virt/qemu/migration/migration.c:127: migrate_get_current: Assertion `current_migration' failed.
  Aborted (core dumped)

What about just doing:

    qemu_global_option("migration.only-migratable=true");

>                  break;
>              case QEMU_OPTION_nodefaults:
>                  has_defaults = 0;
> -- 
> 2.7.4
> 

-- 
Eduardo