Re: [Qemu-devel] [PATCH] hw/pci: disable pci-bridge's shpc by default

[Marcel Apfelbaum]

On 11/16/2016 06:44 PM, Andrew Jones wrote:
> On Sat, Nov 05, 2016 at 06:46:34PM +0200, Marcel Apfelbaum wrote:
> > On 11/03/2016 09:40 PM, Michael S. Tsirkin wrote:
> > > On Thu, Nov 03, 2016 at 01:05:44PM +0200, Marcel Apfelbaum wrote:
> > > > On 11/03/2016 06:18 AM, Michael S. Tsirkin wrote:
> > > > > On Wed, Nov 02, 2016 at 05:16:42PM +0200, Marcel Apfelbaum wrote:
> > > > > > The shpc component is optional while  ACPI hotplug is used
> > > > > > for hot-plugging PCI devices into a PCI-PCI bridge.
> > > > > > Disabling the shpc by default will make slot 0 usable at boot time
> > > >
> > > > Hi Michael
> > > >
> > > > > at the cost of breaking all hotplug for all non-acpi users.
> > > >
> > > > Do we have a non-acpi user that is able to use the shpc component as-is today?
> > >
> > > power and some arm systems I guess?
> >
> > Adding Andrew , maybe he can give us an answer.
>
> Not really :-) My lack of PCI knowledge makes that difficult. I'd be happy
> to help with an experiment though. Can you give me command line arguments,
> qmp commands, etc. that I should use to try it out? I imagine I should
> just boot an ARM guest using DT (instead of ACPI) and then attempt to
> hotplug a PCI device. I'm not sure, however, what, if any, special
> configuration I need in order to ensure I'm testing what you're
> interested in.

Hi Drew,


Just run QEMU with '-device pci-bridge,chassis_nr=1,id=bridge1 -monitor stdio'
with an ARM guest using DT and wait until the guest finish booting.

Then run at hmp:
device_add virtio-net-pci,bus=bridge1,id=net2

Next run lspci in the guest to see the new device.


BTW, will an ARM guest run 'fast' enough to be usable on a x86 machine?
If yes, any pointers on how to create such a guest?


Thanks,
Marcel




> Thanks,
> drew


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