From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:49882) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gmGK0-0004kl-Qc for qemu-devel@nongnu.org; Wed, 23 Jan 2019 06:03:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gmGJv-0007Xa-BP for qemu-devel@nongnu.org; Wed, 23 Jan 2019 06:03:52 -0500 Date: Wed, 23 Jan 2019 12:03:37 +0100 From: Cornelia Huck Message-ID: <20190123120337.72eb7637.cohuck@redhat.com> In-Reply-To: <20190121134249.16615-2-david@redhat.com> References: <20190121134249.16615-1-david@redhat.com> <20190121134249.16615-2-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 1/2] s390x/pci: Introduce unplug requests and split unplug handler List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Hildenbrand Cc: qemu-devel@nongnu.org, qemu-s390x@nongnu.org, Collin Walling , Thomas Huth , Christian Borntraeger , Richard Henderson On Mon, 21 Jan 2019 14:42:48 +0100 David Hildenbrand 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?