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pcie: implement slot power control for pcie root ports 

With this patch hot-plugged pci devices will only be visible to the
guest if the guests hotplug driver has enabled slot power.

This should fix the hot-plug race which one can hit when hot-plugging
a pci device at boot, while the guest is in the middle of the pci bus
scan.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20211111130859.1171890-3-kraxel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Gerd Hoffmann 2021-11-11 14:08:55 +01:00 committed by Michael S. Tsirkin
parent 23786d1344
commit d5daff7d31
1 changed files with 28 additions and 0 deletions
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28
hw/pci/pcie.c
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@ -366,6 +366,29 @@ static void hotplug_event_clear(PCIDevice *dev)
}
}
static void pcie_set_power_device(PCIBus *bus, PCIDevice *dev, void *opaque)
{
bool *power = opaque;
pci_set_power(dev, *power);
}
static void pcie_cap_update_power(PCIDevice *hotplug_dev)
{
uint8_t *exp_cap = hotplug_dev->config + hotplug_dev->exp.exp_cap;
PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(hotplug_dev));
uint32_t sltcap = pci_get_long(exp_cap + PCI_EXP_SLTCAP);
uint16_t sltctl = pci_get_word(exp_cap + PCI_EXP_SLTCTL);
bool power = true;
if (sltcap & PCI_EXP_SLTCAP_PCP) {
power = (sltctl & PCI_EXP_SLTCTL_PCC) == PCI_EXP_SLTCTL_PWR_ON;
}
pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
pcie_set_power_device, &power);
}
/*
* A PCI Express Hot-Plug Event has occurred, so update slot status register
* and notify OS of the event if necessary.
@ -434,6 +457,7 @@ void pcie_cap_slot_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA,
PCI_EXP_LNKSTA_DLLLA);
}
pcie_cap_update_power(hotplug_pdev);
return;
}
@ -451,6 +475,7 @@ void pcie_cap_slot_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
}
pcie_cap_slot_event(hotplug_pdev,
PCI_EXP_HP_EV_PDC | PCI_EXP_HP_EV_ABP);
pcie_cap_update_power(hotplug_pdev);
}
}
@ -625,6 +650,7 @@ void pcie_cap_slot_reset(PCIDevice *dev)
PCI_EXP_SLTSTA_PDC |
PCI_EXP_SLTSTA_ABP);
pcie_cap_update_power(dev);
hotplug_event_update_event_status(dev);
}
@ -705,6 +731,7 @@ void pcie_cap_slot_write_config(PCIDevice *dev,
pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
PCI_EXP_SLTSTA_PDC);
}
pcie_cap_update_power(dev);
hotplug_event_notify(dev);
@ -731,6 +758,7 @@ int pcie_cap_slot_post_load(void *opaque, int version_id)
{
PCIDevice *dev = opaque;
hotplug_event_update_event_status(dev);
pcie_cap_update_power(dev);
return 0;
}