Re: Is it possible to support hotplug device to PXB bridge?

[Igor Mammedov <imammedo@redhat.com>]

On Fri, 22 Apr 2022 09:29:20 +0100
Daniel P. Berrangé <berrange@redhat.com> wrote:

> On Fri, Apr 22, 2022 at 03:17:11PM +0800, Eric Ren wrote:
> > Hi Marcel and all,
> > 
> > It fails when I want to hotplug device to PXB bus. Then, I find this
> > commit that explicitely declares the fact that PXB bus does not support
> > hotplug device onto it.
> > 
> > 7b346c742cd9 ("hw/pxb: declare pxb devices as not hot-pluggable")
> > 
> > Could you please help confirm the possibility to make PXB bus hotpluggable,
> > and the main work to achieve it if possible?  
> 
> Instead of trying to hotplug into the PXB, attach a 'pci-bridge' to the
> PXB and then you can hotplug into the latter instead.

there is no ACPI based hotplug for devices on pxb if I'm not mistaken, so
you'll likely need to enable shpc on pci-bridge.
 
> > Yes, pxb-pcie with Q35 do support hotplug, but we use i440 machine a long way,
> > not  willing to change machine type to have it.  
> 
> With regards,
> Daniel