Re: [Qemu-devel] [PATCH v4] hw/i386: Deprecate the machine types pc-0.10 and pc-0.11

[Paolo Bonzini]

On 25/06/2018 11:05, Thomas Huth wrote:
> The oldest machine type which is still used in a still maintained distro
> is a pc-0.12 based machine type in RHEL6, so everything that is older
> than pc-0.12 should not be used anymore. Thus let's deprecate pc-0.10
> and pc-0.11 so that we can finally remove them in a future release.
> 
> Reviewed-by: Eduardo Habkost <address@hidden>
> Signed-off-by: Thomas Huth <address@hidden>
> ---
>  This is based on a patch that I already sent in 2017. But back then, we
>  were still in progress of discussing our deprecation policies (e.g. auto-
>  matic deprecation for old machine types), and there was no clear consensus
>  whether we should deprecate 0.10 - 0.11, all 0.x or even up to version 1.2.
>  After some iterations and too much discussion, I've forgotten about this
>  patch. Anyway, I think we agreed that at least 0.10 and 0.11 can certainly
>  be removed nowadays, so let's finally get at least those two machine types
>  marked as deprecated! If there is not too much bikeshed-painting discussions
>  anymore and the patch gets finally accepted and we will finally have removed
>  these two types in v3.2, we can resume the discussion about newer machine
>  types afterwards.
> 
>  Note: I don't want to add a QMP interface for this in this patch here,
>  let's keep this small and simple! If we decide that we need a QMP interface,
>  we can do that with a separate patch later.

Queued, thanks.

Paolo

>  v4:
>  - Shorten the deprecation message as requested by Markus
>  - Added Eduardo's Reviewed-by
> 
>  v3:
>  - Do not print the deprecation messages if qtest_enabled()
> 
>  v2:
>  - Renamed deprecation_msg to deprecation_reason
>  - Added information about that field to the MachineClass comment
> 
>  hw/i386/pc_piix.c   |  1 +
>  include/hw/boards.h |  3 +++
>  qemu-doc.texi       |  5 +++++
>  vl.c                | 10 ++++++++--
>  4 files changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index e9b6f06..d357907 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -956,6 +956,7 @@ static void pc_i440fx_0_11_machine_options(MachineClass 
> *m)
>  {
>      pc_i440fx_0_12_machine_options(m);
>      m->hw_version = "0.11";
> +    m->deprecation_reason = "use a newer machine type instead";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_0_11);
>  }
>  
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index ef7457f..79069dd 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -107,6 +107,8 @@ typedef struct {
>  
>  /**
>   * MachineClass:
> + * @deprecation_reason: If set, the machine is marked as deprecated. The
> + *    string should provide some clear information about what to use instead.
>   * @max_cpus: maximum number of CPUs supported. Default: 1
>   * @min_cpus: minimum number of CPUs supported. Default: 1
>   * @default_cpus: number of CPUs instantiated if none are specified. 
> Default: 1
> @@ -166,6 +168,7 @@ struct MachineClass {
>      char *name;
>      const char *alias;
>      const char *desc;
> +    const char *deprecation_reason;
>  
>      void (*init)(MachineState *state);
>      void (*reset)(void);
> diff --git a/qemu-doc.texi b/qemu-doc.texi
> index 282bc3d..16fcb47 100644
> --- a/qemu-doc.texi
> +++ b/qemu-doc.texi
> @@ -2943,6 +2943,11 @@ support page sizes < 4096 any longer.
>  
>  @section System emulator machines
>  
> address@hidden pc-0.10 and pc-0.11 (since 3.0)
> +
> +These machine types are very old and likely can not be used for live 
> migration
> +from old QEMU versions anymore. A newer machine type should be used instead.
> +
>  @section Device options
>  
>  @subsection Block device options
> diff --git a/vl.c b/vl.c
> index d451f45..5d8a9df 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2560,8 +2560,9 @@ static gint machine_class_cmp(gconstpointer a, 
> gconstpointer b)
>              if (mc->alias) {
>                  printf("%-20s %s (alias of %s)\n", mc->alias, mc->desc, 
> mc->name);
>              }
> -            printf("%-20s %s%s\n", mc->name, mc->desc,
> -                   mc->is_default ? " (default)" : "");
> +            printf("%-20s %s%s%s\n", mc->name, mc->desc,
> +                   mc->is_default ? " (default)" : "",
> +                   mc->deprecation_reason ? " (deprecated)" : "");
>          }
>      }
>  
> @@ -4257,6 +4258,11 @@ int main(int argc, char **argv, char **envp)
>  
>      configure_accelerator(current_machine);
>  
> +    if (!qtest_enabled() && machine_class->deprecation_reason) {
> +        error_report("Machine type '%s' is deprecated: %s",
> +                     machine_class->name, machine_class->deprecation_reason);
> +    }
> +
>      /*
>       * Register all the global properties, including accel properties,
>       * machine properties, and user-specified ones.
>