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[Qemu-devel] [PATCH v2 2/6] s390x/pci: Fix hotplugging of PCI bridges
From: |
David Hildenbrand |
Subject: |
[Qemu-devel] [PATCH v2 2/6] s390x/pci: Fix hotplugging of PCI bridges |
Date: |
Wed, 30 Jan 2019 16:57:29 +0100 |
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 <address@hidden>
Signed-off-by: David Hildenbrand <address@hidden>
---
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
*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)
{
@@ -851,26 +866,21 @@ 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);
--
2.17.2
- [Qemu-devel] [PATCH v2 0/6] s390x/pci: remaining hot/un)plug patches, David Hildenbrand, 2019/01/30
- [Qemu-devel] [PATCH v2 1/6] s390x/pci: Fix primary bus number for PCI bridges, David Hildenbrand, 2019/01/30
- [Qemu-devel] [PATCH v2 2/6] s390x/pci: Fix hotplugging of PCI bridges,
David Hildenbrand <=
- [Qemu-devel] [PATCH v2 4/6] s390x/pci: Introduce unplug requests and split unplug handler, David Hildenbrand, 2019/01/30
- [Qemu-devel] [PATCH v2 3/6] s390x/pci: Warn when adding PCI devices without the 'zpci' feature, David Hildenbrand, 2019/01/30
- [Qemu-devel] [PATCH v2 5/6] s390x/pci: Drop release timer and replace it with a flag, David Hildenbrand, 2019/01/30
- [Qemu-devel] [PATCH v2 6/6] s390x/pci: Unplug remaining requested devices on pcihost reset, David Hildenbrand, 2019/01/30