Re: [Qemu-devel] Re: [PATCH 1/6] Make config space accessor host bus trapable

[Michael S. Tsirkin]

On Tue, Jan 05, 2010 at 08:53:52AM +1100, Benjamin Herrenschmidt wrote:
> 
> > Yes, but I think how you program your host to pci bridge is platform 
> > specific,
> > the standard (mostly) applies to what happens below the bridge.  There's
> > no real standard for how PCI host bridge is connected to processor
> > AFAIK, it's by luck we can share code there at all.
> 
> Well, yes and no ... there's a standard on how a PCI host bridge is
> connected in the sense that how normal MMIO accesses go through in term
> of endianness is well defined.
> 

Go through where? From processor to PCI?
Which spec do you refer to?

> How you actually issue config space cycles is a property of a given
> bridge. How you issue IO cycles as well in fact.
> 
> Cheers,
> Ben.