Re: [Qemu-devel] [Qemu-ppc] [PATCH 5/5] pseries: Move XICS initialization before cpu initialization

[David Gibson]

On Fri, Mar 15, 2013 at 01:33:18PM +0100, Alexander Graf wrote:
> 
> On 14.03.2013, at 02:53, David Gibson wrote:
> 
> > Currently, the pseries machine initializes the cpus, then the XICS
> > interrupt controller.  However, to support the upcoming in-kernel XICS
> > implementation we will need to initialize the irq controller before the
> > vcpus.  This patch makes the necesssary rearrangement.  This means the
> 
> We're changing that notion in the in-kernel XICS discussions.  The flow will 
> look like this:
> 
>   * create vcpus
>   * create XICS
>   * foreach (vcpu)
>       * enable_cap(vcpu, CAP_XICS_SERVER, xics_handle)
> 
> However, that means we still need to know the maximum number of
> supported vcpus during the create phase. That number can be bigger
> than smp_cpus though, since you probably want to support hotplug add
> of CPUs later on.
> 
> Can't we just make the number of supported "interrupt servers" a
> constant?

I suppose, but we need an allocation for each one, so its a bit ugly.
In any case although the comment is a bit out of date, this patch also
creates a logical place to put per-cpu XICS initialization which we
will still need for the new interface.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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