Re: [Qemu-devel] Re: [PATCH 0/4] Machine config files

[Michael S. Tsirkin]

On Mon, Jul 06, 2009 at 03:43:23PM +0200, Gerd Hoffmann wrote:
> 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.

Actually at least for pci devices you have the devid/vendor id
register - from this you can know which devices are present.

>  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