Re: [Qemu-devel] [PATCH 3/3] spapr: make irq customizable via qdev

[David Gibson <david@gibson.dropbear.id.au>]

On Wed, May 25, 2011 at 05:13:40PM +0200, Markus Armbruster wrote:
> David Gibson <david@gibson.dropbear.id.au> writes:
> 
> > On Tue, May 24, 2011 at 01:45:07PM +0200, Paolo Bonzini wrote:
> >> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> >> Cc: Alexander Graf <agraf@suse.de>
> >> Cc: David Gibson <david@gibson.dropbear.id.au>
> >> ---
> >>  hw/spapr_vio.c |    8 +++++++-
> >>  1 files changed, 7 insertions(+), 1 deletions(-)
> >> 
> >> diff --git a/hw/spapr_vio.c b/hw/spapr_vio.c
> >> index be535d6..fee4c46 100644
> >> --- a/hw/spapr_vio.c
> >> +++ b/hw/spapr_vio.c
> >> @@ -52,6 +52,10 @@
> >>  static struct BusInfo spapr_vio_bus_info = {
> >>      .name       = "spapr-vio",
> >>      .size       = sizeof(VIOsPAPRBus),
> >> +    .props = (Property[]) {
> >> +        DEFINE_PROP_UINT32("irq", VIOsPAPRDevice, vio_irq_num, 0), \
> >> +        DEFINE_PROP_END_OF_LIST(),
> >> +    },
> >>  };
> >
> > I don't see what the point of this is.  Absolute irq numbers have no
> > special meaning in the XICS context, and the guest kernel will remap
> > them to virtual irqs anyway.
> 
> Are the irq numbers guest-visible?

Yes.

>  If yes, a property may be required
> to keep them stable across migration.  Especially when hot-plug comes
> into play.

Ah, yes, that's a point.

-- 
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