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

[Benjamin Herrenschmidt]

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.

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 .

Cheers,
Ben.