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From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] Re: pci_default_config_write() clean up.
Date: Thu, 7 May 2009 12:57:03 +0100
References: <20090507084019.GA25512%yamahata@valinux.co.jp>
	<20090507111351.GD25512%yamahata@valinux.co.jp>
	<20090507114609.GH32039@redhat.com>
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To: qemu-devel@nongnu.org
Cc: Isaku Yamahata <yamahata@valinux.co.jp>, mtosatti@redhat.com, armbru@redhat.com, "Michael S. Tsirkin" <mst@redhat.com>

On Thursday 07 May 2009, Michael S. Tsirkin wrote:
> On Thu, May 07, 2009 at 08:13:51PM +0900, Isaku Yamahata wrote:
> > On Thu, May 07, 2009 at 01:25:38PM +0300, Michael S. Tsirkin wrote:
> > > > How about callback?
> > >
> > > Yes, I think callbacks have the potential to simplify code.
> > > Would you like to add them on top of my patch then?
> >
> > Okay.
> >
> > > - There's some tricky code there to trigger callbacks only once
> > >   on a multibyte transaction. It would be simpler just to have
> > > per-dword callbacks.  These could get the mask of the written-to bytes
> > > and do if (written_mask & interesting_mask)
> > > 		stuff
> >
> > Are you assuming that word/dword io port access is word/dword aligned?
>
> I think this does not have to be the case in I/O generally.

You can assume all accesses are naturally aligned. The softmmu code will split 
unaligned accesses before devices see them.

Paul