Re: [Qemu-devel] [PATCH for-4.0 0/2] spapr: Fix extended config space accesses

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

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On Mon, Apr 01, 2019 at 07:54:57PM +0200, Greg Kurz wrote:
> Recent commit c2077e2ca0da7 added stricter checks that now prevent
> a guest to access the extended config space of a PCIe device connected
> attached to a PHB on a pseries machine.
> 
> PAPR compatible PHBs act like legacy PCI busses, but they do allow access
> to the full 4k config space of PCIe devices. As discussed several times on
> the list ([1] and [2]), we cannot really change PAPR PHB to have a true
> PCIe root bus since it would call for massive and unwanted changes in
> libvirt.
> 
> This series tries to address the issue with a new PCI bus class method
> that tells if the PCI bus supports extended config space accesses,
> instead of relying on pci_bus_is_express() which wants a PCIe root bus.
> A new legacy PCI bus type is added to implement the PAPR behaviour.
> 
> Note that this fixes a potential 4.0 regression, hence the for-4.0 tag.
> 
> [1] https://lists.gnu.org/archive/html/qemu-devel/2016-10/msg07377.html
>     https://lists.gnu.org/archive/html/qemu-devel/2016-11/msg02839.html
> 
> [2] https://lists.gnu.org/archive/html/qemu-ppc/2017-01/msg00034.html

So, I actually had some patches I'd been working on that address both
the c2077e2ca0da7 issue and the PAPR fixup in what I think is a
cleaner manner.  Can't remember now if I posted and they got lost, or
I didn't get around to posting.

Nonetheless, at this point we're fixing a real regression on PAPR.
I'll look at cleaning this up post 4.0.

Reviewed-by: David Gibson <david@gibson.dropbe

I can take this through my tree if people are ok with that.

-- 
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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