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Date: Sun, 1 Apr 2012 12:06:16 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
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Subject: Re: [Qemu-devel] [PATCHv2] piix: fix up/down races + document
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To: Gleb Natapov <gleb@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>, qemu-devel@nongnu.org, Isaku Yamahata <yamahata@valinux.co.jp>, Gerd Hoffmann <kraxel@redhat.com>, Igor Mammedov <imammedo@redhat.com>, Aurelien Jarno <aurelien@aurel32.net>

On Sun, Apr 01, 2012 at 11:26:18AM +0300, Gleb Natapov wrote:
> On Sun, Apr 01, 2012 at 11:22:33AM +0300, Michael S. Tsirkin wrote:
> > > And if pci-hotplug could be done as cpu-hotplug, then it would simplify pci-hotplug
> > > (guest would only need to read PCI_BASE) and probably it would be possible to unify hotplug
> > > code for pci/cpu. But that for sure will break compatibility.
> > 
> > Which isn't really acceptable.
> > 
> I do not think it should be taken for granted. We should be able to get
> rid of a crud once in a while.

In general, yes. It needs to be well planned several years in
advance though. Something like
http://www.kernel.org/doc/Documentation/feature-removal-schedule.txt
might be a model.

Breaking compatibility would bring very little
gain in this case though, right?

> --
> 			Gleb.