Re: [Qemu-devel] [PATCH v3 5/5] docs: update documentation considering PCIE-PCI bridge

[Marcel Apfelbaum]

On 02/08/2017 19:26, Michael S. Tsirkin wrote:
> On Wed, Aug 02, 2017 at 06:36:29PM +0300, Marcel Apfelbaum wrote:
> > > > > > > Can dmi-pci support shpc? why doesn't it? For compatibility?
> > > > > >
> > > > > > I don't know why, but the fact that it doesn't is the reason libvirt
> > > > > > settled on auto-creating a dmi-pci bridge and a pci-pci bridge under
> > > > > > that for Q35. The reasoning was (IIRC Laine's words correctly) that the
> > > > > > dmi-pci bridge cannot receive hotplugged devices, while the pci-pci
> > > > > > bridge cannot be connected to the root complex. So both were needed.
> > > > > >
> > > > > > Thanks
> > > > > > Laszlo
> > > > >
> > > > > OK. Is it true that dmi-pci + pci-pci under it will allow hotplug
> > > > > on Q35 if we just flip the bit in _OSC?
> > > >
> > > > Marcel, what say you?... :)
> >
> > Good news, works with:
> >     -device i82801b11-bridge,id=b1
> >     -device pci-bridge,id=b2,bus=b1,chassis_nr=1,msi=off
>
> And presumably it works for modern windows?
> OK, so it looks like patch 1 is merely a bugfix, I'll merge it for 2.10.

Tested with Win10, I think is OK to merge if for 2.10.

> > Notice bridge's msi=off until the following kernel bug will be merged:
> >    https://www.spinics.net/lists/linux-pci/msg63052.html
>
> Does libvirt support msi=off as a work-around?

Adding Laine, maybe he has the answer.

Thanks,
Marcel



> > Thanks,
> > Marcel