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

[Greg Kurz <groug@kaod.org>]

On Mon, 27 Aug 2018 08:21:48 +0200
Thomas Huth <thuth@redhat.com> wrote:

> 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 <clg@kaod.org> wrote:
> >>  
> >>> On 08/24/2018 05:09 PM, Peter Maydell wrote:  
> >>>> On 21 August 2018 at 05:33, David Gibson <david@gibson.dropbear.id.au> wrote:    
> >>>>> From: Cédric Le Goater <clg@kaod.org>  
> [...]
> >>> 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

Hmm... how would you do that ?

> ... not sure whether that works though, since there is a class
> hierarchy (TYPE_PCI_HOST_BRIDGE) in between?
> 

Also, as said above, we have the very same problem with spapr_cpu_core,
which is definitely not a sysbus device...

Cheers,

--
Greg

>  Thomas