Re: [PATCH 0/6] RfC: try improve native hotplug for pcie root ports

[Daniel P . Berrangé]

On Thu, Nov 11, 2021 at 03:20:07AM -0500, Michael S. Tsirkin wrote:
> On Thu, Nov 11, 2021 at 08:53:06AM +0100, Gerd Hoffmann wrote:
> >   Hi,
> > 
> > > Given it's a bugfix, and given that I hear through internal channels
> > > that QE results so far have been encouraging, I am inclined to bite the
> > > bullet and merge this for -rc1.
> > 
> > Fine with me.
> > 
> > > I don't think this conflicts with Julia's patches as users can still
> > > disable ACPI hotplug into bridges.  Gerd, agree?  Worth the risk?
> > 
> > Combining this with Julia's patches looks a bit risky to me and surely
> > needs testing.  I expect the problematic case is both native and acpi
> > hotplug being enabled.
> >  When the guest uses acpi hotplug nobody will
> > turn on slot power on the pcie root port ...
> 
> I'm not sure I understand what the situation is, and how to trigger it.
> Could you clarify pls?
> 
> > I'd suggest to just revert to pcie native hotplug for 6.2.
> 
> Hmm that kind of change seems even riskier to me. I think I'll try with
> Igor's patches.

Why would it be risky ? PCIE native hotplug is what we've used in
QEMU for years & years, until 6.1 enabled the buggy ACPI hotplug.
The behaviour of the current PCIE native hotplug impl is a known
quantity.

Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|