Re: [Qemu-devel] [PATCH] Change virtio-console to PCI_CLASS_SERIAL_OTHER

[Dor Laor <dlaor@redhat.com>]

Mark McLoughlin wrote:
> On Fri, 2009-05-29 at 10:43 +0100, Mark McLoughlin wrote:
>
>   
>> The more I think about it, no matter how much linear ABI versioning
>> sucks, it's possibly the only way to solve this in a reasonably usable
>> manners. Distros would just have to suck it up and agree that if they
>> cherry-pick an ABI changing patch, they must update the entire ABI to
>> the newer upstream ABI version.
>>     
>
> Okay, how about this:
>
>   - Add a saveabi monitor command
>
>   - Whenever libvirt starts a guest or hotplugs a device, it executes
>     saveabi and retains the output
>
>   - The abi can be restored with qemu -loadabi or the loadabi monitor 
>     command
>
>   - The abi file doesn't describe the device model, it merely gives 
>     hints for building the device model which is described on the
>     command line
>
>   - If the abi file contains details of a device which is not listed on 
>     the command line, it's just ignored and not included in the next 
>     saveabi
>
>   - If the abi file is missing details of a device which is listed on 
>     the command line, the device is constructed using the defaults and 
>     included in the next saveabi
>
>   - This means the abi file is opaque to the management tools - unlike 
>     the machine config file, libvirt would not need to modify it when
>     devices are added or removed by the user
>   
IMO it shouldn't be opaque and we might use the same config file for the 
abi too.
The notion of abi config is indeed required and most of the times, mgmt 
tools won't
need to deal with it.

But, let's say for instance that the user with certain abi configs, now 
change some
existence of pci device, bios memory mapping, etc. In the case mgmt 
should automatically
adjust both config files to minimize the effect on the guest and not to 
create a conflict.

> Cheers,
> Mark.
>
>
>
>