Re: [Qemu-devel] [Qemu-ppc] [PULL 25/26] spapr_pci: factorize the use of SPAPR_MACHINE_GET_CLASS()

[Thomas Huth]

On 2018-08-24 18:43, Cédric Le Goater wrote:
> On 08/24/2018 05:38 PM, Greg Kurz wrote:
>> On Fri, 24 Aug 2018 17:30:12 +0200
>> Cédric Le Goater <address@hidden> wrote:
>>
>>> On 08/24/2018 05:09 PM, Peter Maydell wrote:
>>>> On 21 August 2018 at 05:33, David Gibson <address@hidden> wrote:  
>>>>> From: Cédric Le Goater <address@hidden>
[...]
>>> Is there a way to specify which device type can or can not be 
>>> plugged on a machine ? 
>>>
>>> I suppose we cannot use : 
>>>
>>>     machine_class_allow_dynamic_sysbus_dev() 
>>>
>>> for cold plugged devices. Or can we ? That would be better.
>>>
>>
>> Hmm... not sure this would help. The root problem is that many
>> places in spapr_pci and spapr_cpu_core assume the machine is
>> sPAPR.
> 
> which is a perfectly legitimate assumption for a sPAPR only device,
> same for spapr_cpu_core. I would think. Shouldn't we enforce 
> the restriction at the machine level instead and not at the device
> level ? 
> 
> I thought that was the purpose of commit 0bd1909da606 ("machine: 
> Replace has_dynamic_sysbus with list of allowed devices"), to 
> make sure machines had a predefined list of user-creatable devices.

The "spapr-pci-host-bridge" is explicitly marked with
"dc->user_creatable = true" - so it is creatable everywhere. You could
try whether it is possible to make it only creatable via the white list
instead ... not sure whether that works though, since there is a class
hierarchy (TYPE_PCI_HOST_BRIDGE) in between?

 Thomas