[libvirt] Non-contiguous NUMA cell numbers

[Daniel P. Berrange]

On Wed, Dec 23, 2015 at 05:14:16PM +0100, Andrea Bolognani wrote:
> Hi all,
> 
> libvirt currently doesn't allow you to configure a guest with something
> like
> 
>   <cpu>
>     <topology sockets='2' cores='5' threads='8'/>
>     <numa>
>       <cell id='0' cpus='0-39' memory='1048576' unit='KiB'/>
>       <cell id='16' cpus='40-79' memory='1048576' unit='KiB'/>
>     </numa>
>   </cpu>
> 
> with the following error:
> 
>   XML error: Exactly one 'cell' element per guest NUMA cell allowed,
>   non-contiguous ranges or ranges not starting from 0 are not allowed
> 
> The error message is very specific about not allowing gaps in NUMA cell
> numbering; however, on the very same host, I have
> 
>   $ numactl --hard | head -1
>   available: 4 nodes (0-1,16-17)
> 
> so gaps in numbering are definitely possible, at least on ppc64.

Well that says Linux supports gaps, but does QEMU actually allow
us to specify gaps ?

Regards,
Daniel
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