[libvirt] [PATCHv2 4/6] API: Introduce VIR_DOMAIN_VCPU_AGENT, for agent based CPU hot(un)plug

[Peter Krempa]

On 04/16/13 19:41, Daniel P. Berrange wrote:
> On Tue, Apr 16, 2013 at 04:00:10PM +0200, Peter Krempa wrote:
>> This flag will allow to use qemu guest agent commands to disable
>> (offline) and enable (online) processors in a live guest that has the
>> guest agent running.
>
> How do guest CPU offline/online state changes relate
> to the offline/online state changes we have traditionally
> done via the monitor.
>
> ie if we offline a CPU with the guest agent, will then
> now be visible in the state via the monitor ? And the
> reverse ?

If you modify the guest state via agent it is not visible to the host 
(except for the VCPU not consuming cpu time).

If you hotplug/unplug cpus via the monitor, the cpu is added/removed to 
the guest and thus visible in the agent output.

Peter