Re: [PATCH 1/2] hw/core: Add bql_interrupt flag to CPUClass

[Eduardo Habkost]

On Sun, Aug 02, 2020 at 05:05:04PM +0100, Alex Bennée wrote:
> 
> Eduardo Habkost <ehabkost@redhat.com> writes:
> 
> > On Fri, Jul 31, 2020 at 03:14:02PM -0400, Robert Foley wrote:
> >> On Fri, 31 Jul 2020 at 13:44, Eduardo Habkost <ehabkost@redhat.com> wrote:
> >> > >
> >> > > +static inline void cpu_class_disable_bql_interrupt(CPUClass *cc)
> >> > > +{
> >> > > +    cc->bql_interrupt = false;
> >> > > +}
> >> >
> >> > Class data is not supposed to change outside class_init.  Why do
> >> > you need this function?  I don't see it being used anywhere in
> >> > this series.
> >> 
> >> This function was to be called from changes in a later patch series
> >> that depend on these changes.  BTW,  I added a correction above,
> >> it should be disable, not enable.  The idea is that it is initialized to 
> >> true,
> >> but then the per arch changes would use this call at init time to set
> >> it to false
> >> as needed.
> >
> > If you plan to call it from class_init, I don't think you need a
> > wrapper.  You can simply set cc->bql_interrupt=false directly
> > inside arch-specific class_init functions.
> 
> We just need to be careful of the ordering so the base class init goes
> first. Is that always the case?

Absolutely.  Subclasses overriding class data previously
initialized by the base class is a very common pattern in QOM
code.

-- 
Eduardo