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Date: Wed, 22 Dec 2010 17:00:45 +0900
From: Isaku Yamahata <yamahata@valinux.co.jp>
Subject: Re: [Qemu-devel] Re: [PATCH] pci: disable migration of p2p bridge
Message-ID: <20101222080045.GA7603@valinux.co.jp>
References: <ad4668c6482905c5c0f3c73bfbd9d58d449be04b.1292987590.git.yamahata@valinux.co.jp>
	<20101222062716.GC7814@redhat.com>
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Blue Swirl <blauwirbel@gmail.com>, Alex Williamson <alex.williamson@redhat.com>, qemu-devel@nongnu.org

On Wed, Dec 22, 2010 at 08:27:17AM +0200, Michael S. Tsirkin wrote:
> On Wed, Dec 22, 2010 at 12:13:43PM +0900, Isaku Yamahata wrote:
> > Right now pcibus_get_dev_path() isn't migration save because
> > bus number/secondary bus number are set by guest OS.
> > So it can't be used reliably for qemu internal id.
> > 
> > For 0.14 release, disable p2p bridge migration at the moment.
> > Once pcibus_get_dev_path() is fixed, this patch should be reverted.
> > It will be addressed for 0.15 release.
> > 
> > Cc: "Michael S. Tsirkin" <mst@redhat.com>
> > Cc: Alex Williamson <alex.williamson@redhat.com>
> > Cc: Blue Swirl <blauwirbel@gmail.com>
> > Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
> 
> 
> Hmm, haven't looked into this deeply - can we do this in one place
> when the bridge is created?

Unfortunately it's not easy. It requires revising
register_device_unmigratable(). I have to admit this patch is ugly. 

This patch is temporal work around and should be reverted eventually.
So I think it is better to address the original issue (allowing migration
of p2p bridge) instead of addressing register_device_unmigratable().

thanks
-- 
yamahata