Re: [Qemu-devel] [PATCH 1/3] migration: Add a new option to enable only-migratable

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

* Ashijeet Acharya (ashijeetacharya@gmail.com) wrote:
> Add a new option "--only-migratable" in qemu which will allow to add
> only those devices which will not fail qemu after migration. Devices
> set with the flag 'unmigratable' cannot be added when this option will
> be used.
> 
> Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
> ---
>  include/migration/migration.h |  3 +++
>  qemu-options.hx               | 10 ++++++++++
>  vl.c                          |  4 ++++
>  3 files changed, 17 insertions(+)
> 
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index c309d23..40b3697 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -38,6 +38,9 @@
>  #define QEMU_VM_COMMAND              0x08
>  #define QEMU_VM_SECTION_FOOTER       0x7e
>  
> +/* for vl.c */
> +extern int only_migratable;
> +
>  struct MigrationParams {
>      bool blk;
>      bool shared;
> diff --git a/qemu-options.hx b/qemu-options.hx
> index c534a2f..7cc2cc5 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -3574,6 +3574,16 @@ be used to change settings (such as migration parameters) prior to issuing
>  the migrate_incoming to allow the migration to begin.
>  ETEXI
>  
> +DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \
> +    "-only-migratable     allow only migratable devices\n", QEMU_ARCH_ALL)
> +STEXI
> +@item -only-migratable
> +@findex -only-migratable
> +Don't allow adding devices that will fail QEMU after migration. Devices set with
> +the flag unmigratable are not allowed to be added neither statically nor
> +dynamically
> +ETEXI

Can I suggest rewording that as:
Only allow migratable devices.  Devices will not be allowed to enter an unmigratable
state.

>  DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
>      "-nodefaults     don't create default devices\n", QEMU_ARCH_ALL)
>  STEXI
> diff --git a/vl.c b/vl.c
> index d77dd86..82bffb9 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -180,6 +180,7 @@ bool boot_strict;
>  uint8_t *boot_splash_filedata;
>  size_t boot_splash_filedata_size;
>  uint8_t qemu_extra_params_fw[2];
> +int only_migratable = 0; /* turn it off unless user states otherwise */
>  
>  int icount_align_option;
>  
> @@ -3914,6 +3915,9 @@ int main(int argc, char **argv, char **envp)
>                  }
>                  incoming = optarg;
>                  break;
> +            case QEMU_OPTION_only_migratable:
> +                only_migratable = 1;
> +                break;
>              case QEMU_OPTION_nodefaults:
>                  has_defaults = 0;
>                  break;

Does this need to go in the 'first pass of option parsing' loop
to make sure that it doesn't matter which order it's in and it
stops other devices on the command line?

Dave

> -- 
> 2.6.2
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK