Re: [Qemu-devel] [PATCH] pc: reduce duplication in compat machine types

["Andreas Färber" <afaerber@suse.de>]

Am 26.03.2012 11:40, schrieb Michael S. Tsirkin:
> Make it easier to add compat properties, by
> adding macros for properties duplicated across
> machine types.
> 
> Note: there could be bugs in compat properties,
> this patch does not attempt to address them,
> the code is bug for bug identical to the original.
> 
> Tested by: generated a preprocessed file, sorted and
> compared to sorted original.
> Lightly tested on x86_64.
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> 
> I've put the above on my branch as it's needed for
> fixing balloon pci class. Let me know if there are
> any objections.

Better reusing code is certainly a good idea. I wonder though if we
might ever get into a situation where things change back and forth. I'd
hope that properties are processed top to bottom so that, e.g.,
PC_COMPAT_1_0, { ... } can overwrite 0_15 compat properties inherited
through 1_0.

Andreas

> 
>  hw/pc_piix.c |  288 +++++++++++++++-------------------------------------------
>  1 files changed, 73 insertions(+), 215 deletions(-)
> 
> diff --git a/hw/pc_piix.c b/hw/pc_piix.c
> index 3f99f9a..e39ef69 100644
> --- a/hw/pc_piix.c
> +++ b/hw/pc_piix.c
> @@ -372,50 +372,69 @@ static QEMUMachine pc_machine_v1_1 = {
>      .is_default = 1,
>  };
>  
> +#define PC_COMPAT_1_0 \
> +        {\
> +            .driver   = "pc-sysfw",\
> +            .property = "rom_only",\
> +            .value    = stringify(1),\
> +        }, {\
> +            .driver   = "isa-fdc",\
> +            .property = "check_media_rate",\
> +            .value    = "off",\
> +        }
> +
>  static QEMUMachine pc_machine_v1_0 = {
>      .name = "pc-1.0",
>      .desc = "Standard PC",
>      .init = pc_init_pci,
>      .max_cpus = 255,
>      .compat_props = (GlobalProperty[]) {
> -        {
> -            .driver   = "pc-sysfw",
> -            .property = "rom_only",
> -            .value    = stringify(1),
> -        }, {
> -            .driver   = "isa-fdc",
> -            .property = "check_media_rate",
> -            .value    = "off",
> -        },
> +        PC_COMPAT_1_0,
>          { /* end of list */ }
>      },
>  };
[snip]

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