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Date: Mon, 28 Jan 2019 12:27:16 +0100
From: Cornelia Huck <cohuck@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v3 1/2] s390x/pci: Introduce unplug
 requests and split unplug handler
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To: David Hildenbrand <david@redhat.com>
Cc: qemu-devel@nongnu.org, qemu-s390x@nongnu.org, Collin Walling <walling@linux.ibm.com>, Thomas Huth <thuth@redhat.com>, Christian Borntraeger <borntraeger@de.ibm.com>, Richard Henderson <rth@twiddle.net>

On Wed, 23 Jan 2019 12:08:37 +0100
David Hildenbrand <david@redhat.com> wrote:

> On 23.01.19 12:03, Cornelia Huck wrote:
> > On Mon, 21 Jan 2019 14:42:48 +0100
> > David Hildenbrand <david@redhat.com> wrote:
> >   
> >> PCI on s390x is really weird and how it was modeled in QEMU might not have
> >> been the right choice. Anyhow, right now it is the case that:
> >> - Hotplugging a PCI device will silently create a zPCI device
> >>   (if none is provided)
> >> - Hotunplugging a zPCI device will unplug the PCI device (if any)
> >> - Hotunplugging a PCI device will unplug also the zPCI device
> >> As far as I can see, we can no longer change this behavior. But we
> >> should fix it.
> >>
> >> Both device types are handled via a single hotplug handler call. This
> >> is problematic for various reasons:
> >> 1. Unplugging via the zPCI device allows to unplug PCI bridges as
> >>    checks are not performed - bad.  
> > 
> > Maybe I'm confused here, but how can a zPCI device couple with a bridge?
> >   
> 
> I was confused, bridges don't attach to a zPCI device. So this remark is
> invalid. Thanks!
> 

Ok, I can remove point 1 when applying.