Re: [Qemu-devel] [PATCH V4] hw/pxb: add chassis_nr property

[Marcel Apfelbaum]

On 03/17/2016 12:02 PM, Cao jin wrote:
> hi
>
> On 03/15/2016 07:44 PM, Marcel Apfelbaum wrote:
> > On 03/15/2016 10:00 AM, Cao jin wrote:
>
> > > And I have another personal question: In qemu design, it seems every
> > > pci bridge reside in a separate chassis, what`s benefit?  why don`t
> > > put them all in the main chassis?
> >
> > Please have a look on pci-to-pci bridge specification, chapter 13, slot
> > numbering.
>
> thanks for the hint.
> I still have a question: in docs/pci_expander_bridge.txt, it says: create a 
> TYPE_PCI_BRIDGE_DEV to enable hotplug support.
> But I didn`t see it can hotplug as following step:
>
> 1: ./qemu-system-x86_64 -device pxb,id=br,bus=pci.0,bus_nr=2 -hda linux.img 
> -smp 2 --enable-kvm -m 1024 -monitor stdio
>
> 2: in monitor, type: device_add e1000,bus=br
> result: no message output to monitor, and don`t see e1000 nic in guest
>
> Is is a bug or I test it in a wrong way?

Hi,

You used hot-plug correctly, it doesn't work yet since I am still working on 
this feature.
The bridge gives us the basics environment for hot-plug, what is missing is ACPI 
"bsel" mechanism.

Thanks,
Marcel

>