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Date: Fri, 6 May 2016 15:44:10 +0530
From: Bharata B Rao <bharata@linux.vnet.ibm.com>
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Subject: Re: [Qemu-devel] [RFC PATCH v2.1 10/12] spapr: CPU hotplug support
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To: Igor Mammedov <imammedo@redhat.com>
Cc: qemu-devel@nongnu.org, mjrosato@linux.vnet.ibm.com, thuth@redhat.com, pkrempa@redhat.com, ehabkost@redhat.com, aik@ozlabs.ru, armbru@redhat.com, agraf@suse.de, borntraeger@de.ibm.com, qemu-ppc@nongnu.org, pbonzini@redhat.com, mdroth@linux.vnet.ibm.com, afaerber@suse.de, david@gibson.dropbear.id.au

On Fri, May 06, 2016 at 10:57:21AM +0200, Igor Mammedov wrote:
> On Thu, 31 Mar 2016 14:09:19 +0530
> Bharata B Rao <bharata@linux.vnet.ibm.com> wrote:
> 
> > Set up device tree entries for the hotplugged CPU core and use the
> > exising RTAS event logging infrastructure to send CPU hotplug notification
> > to the guest.
> 
> perhaps you could reuse:
> 
> [RFC,20/42] machine: add cpu-hotplug machine option
> http://patchwork.ozlabs.org/patch/617516/
> 
> to enable cpu hotplug explicitly,
> and by default machine would be hotplug less saving resources.

We explicitly enable hotplug for specific machine type versions by
setting sPAPRMachineClass.dr_cpu_enabled. So we check it to ensure
that there are no DR connector objects (the resources needed for hotplug)
created for a machine that doesn't support CPU hotplug. Similar is
the case for memory hotplug.

So you are suggesting that we switch from sAPPR specific check
(sPAPRMachineClass.dr_cpu_enabled) to the above MachineState.cpu_hotplug ?

Regards,
Bharata.