hw/pcie: better hotplug/hotunplug support
The current code is broken: it does surprise removal which crashes guests. Reimplemented the steps: - Hotplug triggers both 'present detect change' and 'attention button pressed'. - Hotunplug starts by triggering 'attention button pressed', then waits for the OS to power off the device and only then detaches it. Fixes CVE-2014-3471. Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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			@ -258,7 +258,8 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
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    pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
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                               PCI_EXP_SLTSTA_PDS);
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    pcie_cap_slot_event(PCI_DEVICE(hotplug_dev), PCI_EXP_HP_EV_PDC);
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    pcie_cap_slot_event(PCI_DEVICE(hotplug_dev),
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                        PCI_EXP_HP_EV_PDC | PCI_EXP_HP_EV_ABP);
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}
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void pcie_cap_slot_hot_unplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
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			@ -268,10 +269,7 @@ void pcie_cap_slot_hot_unplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
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    pcie_cap_slot_hotplug_common(PCI_DEVICE(hotplug_dev), dev, &exp_cap, errp);
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    object_unparent(OBJECT(dev));
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    pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
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                                 PCI_EXP_SLTSTA_PDS);
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    pcie_cap_slot_event(PCI_DEVICE(hotplug_dev), PCI_EXP_HP_EV_PDC);
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    pcie_cap_slot_push_attention_button(PCI_DEVICE(hotplug_dev));
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}
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/* pci express slot for pci express root/downstream port
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			@ -383,6 +381,11 @@ void pcie_cap_slot_reset(PCIDevice *dev)
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    hotplug_event_update_event_status(dev);
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}
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static void pcie_unplug_device(PCIBus *bus, PCIDevice *dev, void *opaque)
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{
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    object_unparent(OBJECT(dev));
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}
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void pcie_cap_slot_write_config(PCIDevice *dev,
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                                uint32_t addr, uint32_t val, int len)
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{
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			@ -407,6 +410,22 @@ void pcie_cap_slot_write_config(PCIDevice *dev,
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                        sltsta);
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    }
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    /*
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     * If the slot is polulated, power indicator is off and power
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     * controller is off, it is safe to detach the devices.
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     */
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    if ((sltsta & PCI_EXP_SLTSTA_PDS) && (val & PCI_EXP_SLTCTL_PCC) &&
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        ((val & PCI_EXP_SLTCTL_PIC_OFF) == PCI_EXP_SLTCTL_PIC_OFF)) {
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            PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(dev));
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            pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
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                                pcie_unplug_device, NULL);
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            pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
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                                         PCI_EXP_SLTSTA_PDS);
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            pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
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                                       PCI_EXP_SLTSTA_PDC);
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    }
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    hotplug_event_notify(dev);
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    /* 
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