Re: [Qemu-devel] [PATCH v2 0/8] pseries: Allow hotplug of P2P bridges and devices under P2P bridges

[David Gibson]

On Thu, May 30, 2019 at 03:38:23PM +1000, David Gibson wrote:
> PAPR has its own PCI hotplug mechanism which we implemented quite a
> while ago.  However, we weren't able to hotplug devices under PCI
> bridges, because the pci-bridge code would try to handle the hotplug
> using SHPC which won't work with PAPR.
> 
> We now have the infrastructure in the hotplug core to have the machine
> take control of the hotplug before the bus tries to claim it, which
> lets us address this.  While we're about it, make a bunch of cleanups
> and also allow hot plug of P2P bridges themselves (this turns out to
> be quite straightforward once the rest is in place).
> 
> For now, we don't support hot unplug of bridges - this seems to cause
> problems, at least for a Linux guest.  I suspect the problem is on the
> guest side, but for now just prohibit until we have time to
> investigate properly.

I've fixed the problem Alexey pointed out, and I've merged this
tentatively to the ppc-for-4.1 branch.

> 
> Changes since v1:
>  * Added proper cover letter
>  * Addressed some minor comments
> 
> David Gibson (8):
>   spapr: Clean up device node name generation for PCI devices
>   spapr: Clean up device tree construction for PCI devices
>   spapr: Clean up dt creation for PCI buses
>   spapr: Clean up spapr_drc_populate_dt()
>   spapr: Clean up DRC index construction
>   spapr: Don't use bus number for building DRC ids
>   spapr: Direct all PCI hotplug to host bridge, rather than P2P bridge
>   spapr: Allow hot plug/unplug of PCI bridges and devices under PCI
>     bridges
> 
>  hw/ppc/spapr.c              |  25 +-
>  hw/ppc/spapr_drc.c          |  13 +-
>  hw/ppc/spapr_pci.c          | 486 ++++++++++++++++++++++--------------
>  include/hw/pci-host/spapr.h |   4 +-
>  include/hw/ppc/spapr_drc.h  |   3 +-
>  5 files changed, 327 insertions(+), 204 deletions(-)
> 

-- 
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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