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

[Daniel P. Berrange]

On Wed, Apr 17, 2013 at 08:47:01AM +0200, Peter Krempa wrote:
> 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).

So this isn't really VCPU hotplug then. It is just toggling
whether the guest OS is scheduling things on that VCPU or
not. As such IMHO, we should not be overloading the existing
API with this functionality - we should have strictly separate
APIs for controlling guest OS vCPU usage.

Daniel
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