From 72cc005ad139d9d5d4bf2cb7402cf730c6726fd3 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Wed, 17 Apr 2019 13:57:37 +0100 Subject: [PATCH 20/24] s390x/pci: Fix hotplugging of PCI bridges RH-Author: Cornelia Huck Message-id: <20190417135741.25297-21-cohuck@redhat.com> Patchwork-id: 85801 O-Subject: [RHEL-8.1.0 qemu-kvm PATCH v2 20/24] s390x/pci: Fix hotplugging of PCI bridges Bugzilla: 1699070 RH-Acked-by: David Hildenbrand RH-Acked-by: Thomas Huth RH-Acked-by: Jens Freimann From: David Hildenbrand 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 subordinate 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 Message-Id: <20190130155733.32742-3-david@redhat.com> Reviewed-by: Collin Walling Signed-off-by: Cornelia Huck (cherry picked from commit 150f462538a6f3b78efe785c911669375032b0d2) Signed-off-by: Cornelia Huck Signed-off-by: Danilo C. L. de Paula --- 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 309ad79..a0f7245 100644 --- a/hw/s390x/s390-pci-bus.c +++ b/hw/s390x/s390-pci-bus.c @@ -881,6 +881,21 @@ static void s390_pcihost_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, } } +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 = pci_get_bus(dev)->parent_dev; + + old_nr = 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 *dev, Error **errp) { @@ -889,26 +904,21 @@ static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev, S390PCIBusDevice *pbdev = NULL; if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_BRIDGE)) { - BusState *bus; PCIBridge *pb = PCI_BRIDGE(dev); - PCIDevice *pdev = PCI_DEVICE(dev); + pdev = 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); - bus = BUS(&pb->sec_bus); - qbus_set_hotplug_handler(bus, DEVICE(s), errp); + qbus_set_hotplug_handler(BUS(&pb->sec_bus), DEVICE(s), errp); if (dev->hotplugged) { pci_default_write_config(pdev, PCI_PRIMARY_BUS, pci_dev_bus_num(pdev), 1); s->bus_no += 1; pci_default_write_config(pdev, PCI_SECONDARY_BUS, s->bus_no, 1); - do { - pdev = 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 = PCI_DEVICE(dev); -- 1.8.3.1