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Date: Sun, 5 Sep 2010 10:34:11 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
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Subject: [Qemu-devel] Re: [PATCH 12/15] piix_pci: introduce a write_config
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To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Blue Swirl <blauwirbel@gmail.com>, Anthony Perard <anthony.perard@citrix.com>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>

On Fri, Aug 13, 2010 at 02:10:01PM +0100, Stefano Stabellini wrote:
> On Thu, 12 Aug 2010, Blue Swirl wrote:
> > On Thu, Aug 12, 2010 at 2:09 PM,  <stefano.stabellini@eu.citrix.com> wrote:
> > > From: Anthony PERARD <anthony.perard@citrix.com>
> > >
> > > Introduce a write config notifier in piix_pci, so that clients can be
> > > notified every time a pci config write happens.
> > > The patch also makes use of the notification mechanism in
> > > xen_machine_fv.
> > 
> > Will the mechanism be used elsewhere? If not, I'd just add a call to
> > xen_piix_pci_write_config_client() to piix_pci.c. It can be surrounded
> > by Xen #ifdeffery, or you could introduce stubs like kvm-stub.c and
> > friends.
> > 
> 
> we were trying to avoid ifdef's in piix_pci, but if you are OK with just a
> couple of them we'll gladly remove the hook.
> 

I second this. Callbacks complicate code significantly.
If there's a single user we are better off without.

-- 
MST