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Date: Mon, 26 Feb 2018 12:23:56 +0100
From: Cornelia Huck <cohuck@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v1] numa: s390x has no NUMA
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To: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Hildenbrand <david@redhat.com>, qemu-s390x@nongnu.org, qemu-devel@nongnu.org, Eduardo Habkost <ehabkost@redhat.com>

On Mon, 26 Feb 2018 12:07:43 +0100
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> On 02/26/2018 11:35 AM, Cornelia Huck wrote:
> > On Mon, 26 Feb 2018 11:28:26 +0100
> > David Hildenbrand <david@redhat.com> wrote:
> >   
> >> On 26.02.2018 11:19, Cornelia Huck wrote:  
> >>> On Fri, 23 Feb 2018 18:36:57 +0100
> >>> David Hildenbrand <david@redhat.com> wrote:
> >>>     
> >>>> Right now it is possible to crash QEMU for s390x by providing e.g.
> >>>>     -numa node,nodeid=0,cpus=0-1
> >>>>
> >>>> Problem is, that numa.c uses mc->cpu_index_to_instance_props as an
> >>>> indicator whether NUMA is supported by a machine type. We don't
> >>>> implement NUMA on s390x (and that concept also doesn't really exist).
> >>>> We need mc->cpu_index_to_instance_props for query-cpus.    
> >>>
> >>> Is existence of cpu_index_to_instance_probs the correct indicator for
> >>> numa, then?
> >>>
> >>> OTOH, your patch is straightforward...    
> >>
> >> Maybe it is get_default_cpu_node_id as Christian discovered?  
> > 
> > Yes, that seems like a better candidate for checking.  
> 
> Agreed. 
> As everybody else calls possible_cpu_arch_ids  in cpu_index_to_props
> I am asking myself if we should do that as well anyway?
> 

Making the behaviour consistent with other archs sounds like a good
idea.