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

[Michael S. Tsirkin]

On Mon, Mar 26, 2012 at 02:51:38PM +0200, Avi Kivity wrote:
> On 03/26/2012 11:40 AM, Michael S. Tsirkin wrote:
> > 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.
> >
> >  
> > +#define PC_COMPAT_1_0 \
> > +        {\
> > +            .driver   = "pc-sysfw",\
> > +            .property = "rom_only",\
> > +            .value    = stringify(1),\
> > +        }, {\
> > +            .driver   = "isa-fdc",\
> > +            .property = "check_media_rate",\
> > +            .value    = "off",\
> > +        }
> > +
> 
> Hmm.  how about
> 
> >  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,
> 
> +    .base_machine =  &pc_machine_v1_1;
> 

It's a lot of work, and the result won't be easier to
modify or debug than it already is, IMO.

> Then it would be easier to define machines differentially.

We add new 1 machine each release, so I'm not worried about
adding them easily, adding properies easily happens
between releases so I want to make is simpler.

> >          { /* end of list */ }
> >      },

> 
> -- 
> error compiling committee.c: too many arguments to function