Re: [Qemu-devel] [RFC PATCH 1/1] s390x/css: unresrict cssids

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 11/24/2017 02:27 PM, Cornelia Huck wrote:
> On Fri, 24 Nov 2017 14:01:20 +0100
> Christian Borntraeger <borntraeger@de.ibm.com> wrote:
> 
>> I first liked the idea to have it as a property of the css, but 
>> this is all pretty unclear how to do right. I start to think that going with
>> Halils first patch (a property per virtio device) is going to be the most
>> simple solution without causing any harm. After all as of today we only want 
>> to have a way to tell libvirt that devices can be everywhere. Specifying the
>> default css might be something that we want to have in the future, but here
>> future might even mean never.
> 
> I still don't like the idea of a per-device property, but I agree that
> adding a css property would need too much discussion to get to a
> solution in the near future.
> 
> Is there anything that speaks against a machine property, though? While
> not ideal, I like it better than the per-device one.

In theory this should work. 

In reality it seems more complicated. A per-device property is easy and can be
inspected on the command line (e.g. -device virtio-blk-ccw,help), while a new 
machine property would require to change the qemu help output and qemu-options 
file (which makes it visible for all architectures). Not sure if there are
easier ways to do it. (e.g. QOM-only things, but then we have no command line
way of doing it)