Re: [Qemu-devel] [PATCH qom-next 08/12] target-i386: introduce cpu-model property for x86_cpu

[Andreas Färber]

Am 30.05.2012 00:10, schrieb Igor Mammedov:
> it's probably intermidiate step till cpu modeled as
> sub-classes. After then we probably could drop it.
> 
> However it still could be used for overiding default
> cpu subclasses definition, and probably renamed to
> something like 'features'.
> 
> v2:
>  - remove accidential tcg_* init code move
> 
> Signed-off-by: Igor Mammedov <address@hidden>
> ---
>  cpu-defs.h           |    2 +-
>  hw/pc.c              |   10 ----------
>  target-i386/cpu.c    |   24 ++++++++++++++++++++++++
>  target-i386/helper.c |   17 ++++++++++++-----
>  4 files changed, 37 insertions(+), 16 deletions(-)

For me this is still the big no-go in this series:

* Moving the default cpu_model into cpu_x86_init() buys us nothing IMO,
it duplicates the property setting code and differs from all other
targets where the default CPU is the machine's decision.

* As you rightly point out, we are heading towards sub-classes and that
contradicts this two-step initialization. I don't see how this is an
intermediate step?
I admit, I am the one to blame for not redoing the x86 CPU subclasses
patches yet - major issue being the built-in vs. -cpudef split:
Now that Eduardo refactored the config file reading, I wonder if we can
outsource the built-in CPUs to the config file? If so, then I would
appreciate one of you x86 experts to do that please (may need some
rebasing when the occasional features get added/tweaked). Then I can
base a series on top that initializes CPU subclasses in a consistent way
rather than duplicating data for the builtins just to make -cpudef work
or creating different intermediate subclasses for both types.

* To override CPU features you should think about how to set x86 CPU
features in a QOM way (think QMP), then we can design the infrastructure
for setting them through global properties (or whatever needed) around
it. I honestly don't know what the requirements are in practice, so I
can't make suggestions there without some more feedback.

Regards,
Andreas

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