Re: [Qemu-devel] [PATCH 3/6] target-i386: Register QOM properties for feature flags

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 08 Apr 2015 14:24:35 +0200
Paolo Bonzini <pbonzini@redhat.com> wrote:

> 
> 
> On 08/04/2015 14:20, Eduardo Habkost wrote:
> >> > it would be better to create generic bit property and replace above code with it
> >> > something similar to object_property_add_uint32_ptr()
> > object_property_add_*_ptr() adds read-only properties, and I didn't want
> > to make object_property_add_bit_ptr() inconsistent with the other
> > functions. But maybe it is better to have an inconsistent but reusable
> > API than making the new code non-reusable by keeping it inside
> > target-i386/cpu.c. I will give it a try.
> 
> add_*_ptr() is read-only because read-only properties do not require
> validations (at least that's the common case).  So I think the
> inconsistent API is worse than a local one.
I've had on my todo list adding add_*_ptr_RW() variants
because in common case there isn't any need in validation and
with current API we are forced to duplicate custom setter/getter
every time for trivial type.
For example properties like "level" or "xlevel".

The same goes for generic bitmap setter (i.e.) without validation,
which is what we need in this case. We [could] do validation at realize
time when it's possible to analyze combination of feature flags.

> 
> > BTW, it is on my wishlist to remove the existing duplication in
> > DEFINE_PROP_*(), QAPI, and object_property_add_*(), that are supposed to
> > support the same data types without duplicating code, but this may take
> > a while.
> 
> Yeah, that would be nice...
> 
> Paolo
>