Re: [Qemu-devel] [SeaBIOS] [RFC PATCH 0/2] Allow RedHat PCI bridges reserve more buses than necessary during init

[Marcel Apfelbaum]

On 20/07/2017 9:52, Gerd Hoffmann wrote:
> On Wed, 2017-07-19 at 16:20 +0300, Aleksandr Bezzubikov wrote:
> > Now PCI bridges (and PCIE root port too) get a bus range number in
> > system init,
> > basing on currently plugged devices. That's why when one wants to
> > hotplug another bridge,
> > it needs his child bus, which the parent is unable to provide.
> > The suggested workaround is to have vendor-specific capability in
> > RedHat generic pcie-root-port
> > that contains number of additional bus to reserve on BIOS PCI init.

Hi Gerd,
Thanks for looking into this.

> Where is the qemu patch for this?

On the way, Aleksandr is working on it, should
be ready soon.

> What about window sizes?  IIRC there was a plan to provide allocation
> hints for them too ...

Yes, is in my TODO list, however not as part of Aleksandr's series
which aims to provide PCIe-PCI bridge hotplug support.
I should mention that for this case both Windows and Linux guests
(modern OSes) trigger correctly IO/MEM resource re-balancing
process and succeeds to complete the hotplug operation.

Thanks,
Marcel

> cheers,
>    Gerd