From nobody Mon Feb 9 00:37:33 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1548864150568922.6201853620483; Wed, 30 Jan 2019 08:02:30 -0800 (PST) Received: from localhost ([127.0.0.1]:40300 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gosJo-0002DT-OD for importer@patchew.org; Wed, 30 Jan 2019 11:02:28 -0500 Received: from eggs.gnu.org ([209.51.188.92]:46812) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gosFK-00074w-Hq for qemu-devel@nongnu.org; Wed, 30 Jan 2019 10:57:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gosFJ-0008VC-Dv for qemu-devel@nongnu.org; Wed, 30 Jan 2019 10:57:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41670) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gosFH-0008R9-Gu; Wed, 30 Jan 2019 10:57:47 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4E7D1ED279; Wed, 30 Jan 2019 15:57:43 +0000 (UTC) Received: from t460s.redhat.com (ovpn-116-235.ams2.redhat.com [10.36.116.235]) by smtp.corp.redhat.com (Postfix) with ESMTP id 70001452C; Wed, 30 Jan 2019 15:57:41 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Date: Wed, 30 Jan 2019 16:57:29 +0100 Message-Id: <20190130155733.32742-3-david@redhat.com> In-Reply-To: <20190130155733.32742-1-david@redhat.com> References: <20190130155733.32742-1-david@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 30 Jan 2019 15:57:43 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v2 2/6] s390x/pci: Fix hotplugging of PCI bridges X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Huth , Pierre Morel , David Hildenbrand , Cornelia Huck , Collin Walling , Christian Borntraeger , qemu-s390x@nongnu.org, Richard Henderson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" When hotplugging a PCI bridge right now to the root port, we resolve pci_get_bus(pdev)->parent_dev, which results in a SEGFAULT. Hotplugging really only works right now when hotplugging to another bridge. Instead, we have to properly check if we are already at the root. Let's cleanup the code while at it a bit and factor out updating the subordiante bus number into a separate function. The check for "old_nr < nr" is right now not strictly necessary, but makes it more obvious what is actually going on. Most probably fixing up the topology is not our responsibility when hotplugging. The guest has to sort this out. But let's keep it for now and only fix current code to not crash. Reviewed-by: Thomas Huth Signed-off-by: David Hildenbrand Reviewed-by: Collin Walling --- hw/s390x/s390-pci-bus.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c index b7c4613fde..9b5c5fff60 100644 --- a/hw/s390x/s390-pci-bus.c +++ b/hw/s390x/s390-pci-bus.c @@ -843,6 +843,21 @@ static void s390_pcihost_pre_plug(HotplugHandler *hotp= lug_dev, DeviceState *dev, } } =20 +static void s390_pci_update_subordinate(PCIDevice *dev, uint32_t nr) +{ + uint32_t old_nr; + + pci_default_write_config(dev, PCI_SUBORDINATE_BUS, nr, 1); + while (!pci_bus_is_root(pci_get_bus(dev))) { + dev =3D pci_get_bus(dev)->parent_dev; + + old_nr =3D pci_default_read_config(dev, PCI_SUBORDINATE_BUS, 1); + if (old_nr < nr) { + pci_default_write_config(dev, PCI_SUBORDINATE_BUS, nr, 1); + } + } +} + static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *de= v, Error **errp) { @@ -851,26 +866,21 @@ static void s390_pcihost_plug(HotplugHandler *hotplug= _dev, DeviceState *dev, S390PCIBusDevice *pbdev =3D NULL; =20 if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_BRIDGE)) { - BusState *bus; PCIBridge *pb =3D PCI_BRIDGE(dev); - PCIDevice *pdev =3D PCI_DEVICE(dev); =20 + pdev =3D PCI_DEVICE(dev); pci_bridge_map_irq(pb, dev->id, s390_pci_map_irq); pci_setup_iommu(&pb->sec_bus, s390_pci_dma_iommu, s); =20 - bus =3D BUS(&pb->sec_bus); - qbus_set_hotplug_handler(bus, DEVICE(s), errp); + qbus_set_hotplug_handler(BUS(&pb->sec_bus), DEVICE(s), errp); =20 if (dev->hotplugged) { pci_default_write_config(pdev, PCI_PRIMARY_BUS, pci_dev_bus_num(pdev), 1); s->bus_no +=3D 1; pci_default_write_config(pdev, PCI_SECONDARY_BUS, s->bus_no, 1= ); - do { - pdev =3D pci_get_bus(pdev)->parent_dev; - pci_default_write_config(pdev, PCI_SUBORDINATE_BUS, - s->bus_no, 1); - } while (pci_get_bus(pdev) && pci_dev_bus_num(pdev)); + + s390_pci_update_subordinate(pdev, s->bus_no); } } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) { pdev =3D PCI_DEVICE(dev); --=20 2.17.2