Re: [Qemu-devel] [PATCH 0/4] QOM'ify work for ppc

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, Jan 03, 2017 at 10:02:21PM +0800, 赵小强 wrote:
> Hi，david：
> 
>    To my understanding，what must be put in the realize function  is
>    code which depends on property values. What's the benefit of
>    moving memory region initialization into realize function?  I can
>    not figure out, can you make some explanations?

If nothing else it's better in realize() for consistency with other
devices.

I'm not familiar enough with the details to be sure, but I also think
it's not safe in instance_init.  Once memory regions are registered,
the device can potentially interact with other devices in the virtual
machine.  realize() is sequenced to expect that, instance_init is not.

>     Thanks for your review.
> 
> Best wishes ！
> 
> > 在 2017年1月3日，06:28，David Gibson <david@gibson.dropbear.id.au> 写道：
> > 
> >> On Sat, Dec 31, 2016 at 09:18:27AM +0800, xiaoqiang zhao wrote:
> >> This is some QOM'ify work relate with ppc.
> >> See each commit message for details.
> >> 
> >> xiaoqiang zhao (4):
> >>  hw/gpio: QOM'ify mpc8xxx.c
> >>  hw/ppc: QOM'ify e500.c
> >>  hw/ppc: QOM'ify ppce500_spin.c
> >>  hw/ppc: QOM'ify spapr_vio.c
> >> 
> >> hw/gpio/mpc8xxx.c     | 20 +++++++++++---------
> >> hw/ppc/e500.c         | 17 ++++-------------
> >> hw/ppc/ppce500_spin.c | 18 ++++++++----------
> >> hw/ppc/spapr_vio.c    |  2 --
> >> 4 files changed, 23 insertions(+), 34 deletions(-)
> > 
> > Patches 1-3 all have the same problem - they move memory region
> > initialization and similar to an instance_init function.  This is not
> > how things are generally done in the qdev model.  Instead that phase
> > of initialization should be done from a dc->realize() function.
> > 
> 
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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