Re: [Qemu-devel] [PATCH v6 7/7] hw/pci-bridge: format SeaBIOS-compliant OFW device node for PXB

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jun 17, 2015 at 08:16:30PM +0200, Laszlo Ersek wrote:
> > We do need to agree about the correct paths however, this is host/guest
> > interface which we have to maintain forever, and it's important to get
> > it right. I kept hoping we can come up with something saner than
> > the sequence # but oh well. Do you disagree with the statement
> > that seabios path is currently incorrect? Kevin seems to agree.
> 
> As discussed earlier, there are two questions to consider about the OFW
> devpath pattern
> 
>   /pci-root@N/pci@i0cf8/...
> 
> that SeaBIOS currently recognizes for devices that reside behind extra
> PCI root buses.
> 
> Q1: everything in that pattern that is not "N"
> Q2: what goes into N
> 
> These are independent questions.


Right. But what I was discussing is a different issue.  The point is
that it does not make sense to have /pci@i0cf8 under two hierarchies:
it's the same register.  What happens is that you access /pci@i0cf8 and
then *through that* you access another pci root.  Not the other way
around.  The proposal thus is to switch to /pci@i0cf8/pci-root@N in
seabios, unconditionally - not if (QEMU).  And I thought Kevin agreed
it's a good idea.

Kevin - is this a good summary of your opinion?


-- 
MST