Re: [Qemu-devel] [PATCH 01/17] qidl: add QEMU IDL processor

[Andreas Färber]

Am 11.06.2012 09:20, schrieb Paolo Bonzini:
> Il 11/06/2012 09:13, Andreas Färber ha scritto:
>>>>>> +The first step is to move your device struct definition to a header 
>>>>>> file.  This
>>>>>> +header file should only contain the struct definition and any 
>>>>>> preprocessor
>>>>>> +declarations you need to define the structure.  This header file will 
>>>>>> act as
>>>>>> +the source for the QC IDL compiler.
>>>>
>>>> I don't think this is a fantastic idea -- the device struct should be
>>>> private to the device, and having it in a standalone header file is
>>>> asking for users of the device to illicitly include it and access
>>>> internals that they shouldn't.
>> But that is exactly where realize is headed. PCIBus, a9mp_priv etc.
>> structs will need to be made public so that they can be embedded.
> 
> I thought that was just a convenience choice, not a necessity.  The
> children objects could just as well be heap-allocated.

In that case we'd need to change the instance_init signature. As far as
I've understood from our discussions with Anthony, realize must not
allocate new objects because that may collide with the recursive realize
model, and instance_init is not supposed to fail. Thus the in-place init
demonstrated for i440fx and now adopted for prep_pci and my tegra2.
Saying "the device struct should be private to the device" leaves
virtually no choice, whether for convenience or necessity, and requires
also suggesting a design solution for QOM initialization.

Andreas

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