From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:32848) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1go55o-0002KW-Fh for qemu-devel@nongnu.org; Mon, 28 Jan 2019 06:28:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1go55n-0003we-DG for qemu-devel@nongnu.org; Mon, 28 Jan 2019 06:28:44 -0500 Date: Mon, 28 Jan 2019 12:28:33 +0100 From: Cornelia Huck Message-ID: <20190128122833.4613659a.cohuck@redhat.com> In-Reply-To: <20190123120539.3ca367f9.cohuck@redhat.com> References: <20190121134249.16615-1-david@redhat.com> <20190121134249.16615-3-david@redhat.com> <20190123120539.3ca367f9.cohuck@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 2/2] s390x/pci: Unplug remaining devices on pcihost reset 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 Wed, 23 Jan 2019 12:05:39 +0100 Cornelia Huck wrote: > On Mon, 21 Jan 2019 14:42:49 +0100 > David Hildenbrand wrote: > > > When resetting the guest we should unplug and remove all devices that > > are still pending. Otherwise the fresh guest will see devices that will > > suddenly vanish. > > > > Can be triggered e.g. via > > (hmp) device_add virtio-mouse-pci,id=test > > (hmp) stop > > (hmp) device_del test > > (hmp) system_reset > > (hmp) c > > > > The device will vanish after roughly 5 minutes. With this patch, the > > device will vanish on reboot (S390_RESET_EXTERNAL and S390_RESET_REIPL, > > which reset the pcihost bridge via qemu_devices_reset()). If we want > > these devices to vanish directly on any reset (S390_RESET_MODIFIED_CLEAR > > and S390_RESET_LOAD_NORMAL), we have to modify s390_machine_reset(). But > > I have the feeling that this should not be done for all reset types. > > > > This approach is similar to what's done for acpi PCI hotplug in > > acpi_pcihp_reset() -> acpi_pcihp_update() -> > > acpi_pcihp_update_hotplug_bus() -> acpi_pcihp_eject_slot(). > > > > s390_pci_generate_plug_event()'s will still be generated, I guess this > > is not an issue (same thing could happen right now if the timer expires > > just after reset). > > I'm wondering what the architecture says regarding those events -- can > someone with access to the documentation comment? Ping. Any comments from the IBM folks? > > > > > Signed-off-by: David Hildenbrand > > --- > > hw/s390x/s390-pci-bus.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c > > index bc17a8cf65..b70ae25533 100644 > > --- a/hw/s390x/s390-pci-bus.c > > +++ b/hw/s390x/s390-pci-bus.c > > @@ -1102,6 +1102,14 @@ static void s390_pcihost_reset(DeviceState *dev) > > { > > S390pciState *s = S390_PCI_HOST_BRIDGE(dev); > > PCIBus *bus = s->parent_obj.bus; > > + S390PCIBusDevice *pbdev, *next; > > + > > + /* Unplug all pending devices that were requested to be released */ > > + QTAILQ_FOREACH_SAFE(pbdev, &s->zpci_devs, link, next) { > > + if (pbdev->release_timer) { > > + s390_pcihost_timer_cb(pbdev); > > + } > > + } > > > > s->bus_no = 0; > > pci_for_each_device(bus, pci_bus_num(bus), s390_pci_enumerate_bridge, s); >