[libvirt] [PATCH v1 2/7] pcihp: overwrite hotplug handler recursively from the start

[David Hildenbrand]

On 01.11.18 15:10, Igor Mammedov wrote:
> On Wed, 24 Oct 2018 12:19:25 +0200
> David Hildenbrand <david at redhat.com> wrote:
> 
>> For now, the hotplug handler is not called for devices that are
>> being cold plugged. The hotplug handler is setup when the machine
>> initialization is fully done. Only bridges that were cold plugged are
>> considered.
>>
>> Set the hotplug handler for the root piix bus directly when realizing.
>> Overwrite the hotplug handler of bridges when hotplugging/coldplugging
>> them.
>>
>> This will now make sure that the ACPI PCI hotplug handler is also called
>> for cold-plugged devices (also on bridges) and for bridges that were
>> hotplugged.
>>
>> When trying to hotplug a device to a hotplugged bridge, we now correctly
>> get the error message
>>  "Unsupported bus. Bus doesn't have property 'acpi-pcihp-bsel' set"
>> Insted of going via the standard PCI hotplug handler.
> Erroring out is probably not ok, since it can break existing setups
> where SHPC hotplugging to hotplugged bridge was working just fine before.

The question is if it actually was supposed (and eventually did) work.

If this was the expected behavior (mixing hotplug types), then the
necessary change to this patch would boil down to checking if the bridge
it hot or coldplugged.

> 
> Marcel/Michael what's your take on this change in behaviour?
> CCing libvirt in case they are doing this stuff
> 

Indeed, it would be nice to know if this was actually supposed to work
like this (coldplugged bridges using ACPI hotplug and hotplugged bridges
using SHPC hotplug).


-- 

Thanks,

David / dhildenb