Re: [Qemu-devel] [PATCH v2 1/2] ppc/pnv: Add model for Power8 PHB3 PCIe Host bridge

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

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On Tue, Jul 24, 2018 at 01:49:32PM +1000, Benjamin Herrenschmidt wrote:
> On Tue, 2018-07-24 at 12:14 +1000, David Gibson wrote:
> > > I don't know, is there much shared logic ? And the shared bits are the
> > > subclassing, that's handled that way...
> > > 
> > > This is really a different piece of HW, a separate ICS implementation,
> > > that has its own quirks, is configured via different registers, does
> > > EOI differently etc...
> > > 
> > > Even the resend stuff is done differently, the resend bitmap is
> > > actually SW visible via an IODA table.
> > > 
> > > I mean, we could (maybe we do these days not sure) have an ICS
> > > superclass wrapper on the actual icp_irq() but that's really all there
> > > is to it I think.
> > 
> > Hm, yeah, fair enough.  I realized what I was suggesting would
> > actually need another layer of qirqs than we have, so it's not a good
> > idea after all.  Ok, I'm happy proceeding with exposing icp_irq().
> 
> The only idea I have if you want to keep icp_* private is to put a
> 'helper' in the ICS superclass that the subclass uses to encapsulate
> the ICP call, but at this point it's just churn.

I concur.

> 
> But yeah you really don't want a layer of qirqs, it wouldn't work any
> way, it's really an ICS, it will send messages to the ICP with a XIRR
> value in them etc... just like an ICS, it's not somethign you want
> qirq's for .
> 

-- 
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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