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Date: Wed, 17 Jun 2015 08:58:35 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20150617085742-mutt-send-email-mst@redhat.com>
References: <1434480849-23093-1-git-send-email-dgilbert@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] Migration compatibility for serial
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To: Markus Armbruster <armbru@redhat.com>
Cc: amit.shah@redhat.com, pbonzini@redhat.com, quintela@redhat.com, "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>, qemu-devel@nongnu.org

On Wed, Jun 17, 2015 at 08:52:42AM +0200, Markus Armbruster wrote:
> "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> writes:
> 
> > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> >
> > Older QEMUs dont understand the new (sub)sections that
> > may be generated in the serial device.   Limit their generation
> > to newer machine types.
> 
> Please explain briefly what state migration can lose with old machine
> types, and how this could impact the guest.  The commits adding the
> subsections should have the information[*].  Pointers to them might
> suffice.
> 
> 
> [*] Should != do; I didn't check.

OTOH if we have flags named after specific portions we skip,
and not after qemu versions, this becomes evident from code.