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

[Anthony Liguori <aliguori@us.ibm.com>]

Mark McLoughlin wrote:
> On Wed, 2009-05-27 at 17:37 -0500, Anthony Liguori wrote:
>   
>> This is can't really be a hard rule yet without the machine config, but 
>> we should do our best when we can.
>>     
>
> There's not much point in doing this unless there's some practical way
> to use it.
>
> If we e.g. add a 'class' parameter for virtio-blk and virtio-console,
> we'd also need to add some way for a management tool to figure out what
> the class value is when it initially creates the guest and, for ever
> more, supply that value.
>
> Options I see:
>
>   1) Add a monitor command to query the class values and delay actually 
>      changing the values until the next release cycle
>
>   2) Use 'info version' to achieve this - management tools would need to
>      start retaining the version that guests were created with and
>      supplying that version to qemu on the command line. As you say,
>      though, linear versioning sucks
>
>   3) Decide we can only make these guarantees with the machine config
>      stuff - management tools would need to query a running qemu for a
>      detailed machine config when initially creating the guest and
>      always supply that when later starting the guest
>   

Today, the qdev stuff supports properties for devices.  If you make
class a property of these devices, you would just need something to dump
the device properties for a given device.

I think it should be a relatively straight forward thing today.

Regards,

Anthony Liguori

> Cheers,
> Mark.
>
>