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Date: Mon, 06 Jul 2009 15:43:23 +0200
From: Gerd Hoffmann <kraxel@redhat.com>
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Subject: Re: [Qemu-devel] Re: [PATCH 0/4] Machine config files
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>, Markus Armbruster <armbru@redhat.com>, qemu-devel@nongnu.org

On 07/06/09 14:49, Michael S. Tsirkin wrote:
> On Fri, Jun 12, 2009 at 06:11:24PM +0200, Jan Kiszka wrote:
> Can't we extend loadvm/savevm format to support machine config? It is
> already supported by all devices, it seems that we just need to add some
> detail such as pci addresses, and qemu flags to save/load this config.
> No?

No.  Adding some info to the devices doesn't cut it as you also need to 
know which devices are present in the first place.  Current savevm 
doesn't do that, thats why you have to start the virtual machine with 
the complete set of command line arguments even when resuming / 
migrating.  Once we have a working device tree implementation we can fix 
that too though.  Rough plan is:

   (1) convert drivers to qdev.
   (2) create qdev device tree from config file (probably fdt).

With this in place it is just a little step to also carry this in the 
savevm format:  We just need a to do a qdev->fdt conversion, then we can 
send the device tree as one savevm section and rebuild the vm from that.

cheers,
   Gerd