pcihp: add ACPI PCI hotplug specific is_hotpluggable_bus() callback

Provide pcihp specific callback to check if bus is hotpluggable
and consolidate its scattered hotplug criteria there.
While at it clean up no longer needed
   qbus_set_hotplug_handler(BUS(bus), NULL)
workarounds since callback makes qbus_is_hotpluggable() return
correct answer even if hotplug_handler is set on bus.

PS:
see ("pci: fix 'hotplugglable' property behavior") for details
why callback was introduced.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20230302161543.286002-35-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/acpi/acpi-pci-hotplug-stub.c

@@ -40,3 +40,7 @@ void acpi_pcihp_reset(AcpiPciHpState *s)
     return;
 }
 
+bool acpi_pcihp_is_hotpluggbale_bus(AcpiPciHpState *s, BusState *bus)
+{
+    return true;
+}

hw/acpi/ich9.c

@@ -578,6 +578,12 @@ void ich9_pm_device_unplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
     }
 }
 
+bool ich9_pm_is_hotpluggable_bus(HotplugHandler *hotplug_dev, BusState *bus)
+{
+    ICH9LPCState *lpc = ICH9_LPC_DEVICE(hotplug_dev);
+    return acpi_pcihp_is_hotpluggbale_bus(&lpc->pm.acpi_pci_hotplug, bus);
+}
+
 void ich9_pm_ospm_status(AcpiDeviceIf *adev, ACPIOSTInfoList ***list)
 {
     ICH9LPCState *s = ICH9_LPC_DEVICE(adev);

hw/acpi/pcihp.c

@@ -121,20 +121,6 @@ static void acpi_set_pci_info(bool has_bridge_hotplug)
     }
 }
 
-static void acpi_pcihp_disable_root_bus(void)
-{
-    Object *host = acpi_get_i386_pci_host();
-    PCIBus *bus;
-
-    bus = PCI_HOST_BRIDGE(host)->bus;
-    if (bus && qbus_is_hotpluggable(BUS(bus))) {
-        /* setting the hotplug handler to NULL makes the bus non-hotpluggable */
-        qbus_set_hotplug_handler(BUS(bus), NULL);
-    }
-
-    return;
-}
-
 static void acpi_pcihp_test_hotplug_bus(PCIBus *bus, void *opaque)
 {
     AcpiPciHpFind *find = opaque;
@@ -278,9 +264,6 @@ static void acpi_pcihp_update(AcpiPciHpState *s)
 
 void acpi_pcihp_reset(AcpiPciHpState *s)
 {
-    if (!s->use_acpi_root_pci_hotplug) {
-        acpi_pcihp_disable_root_bus();
-    }
     acpi_set_pci_info(s->use_acpi_hotplug_bridge);
     acpi_pcihp_update(s);
 }
@@ -320,13 +303,6 @@ void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
             object_dynamic_cast(OBJECT(dev), TYPE_PCI_BRIDGE)) {
             PCIBus *sec = pci_bridge_get_sec_bus(PCI_BRIDGE(pdev));
 
-            /* Remove all hot-plug handlers if hot-plug is disabled on slot */
-            if (object_dynamic_cast(OBJECT(dev), TYPE_PCIE_SLOT) &&
-                !PCIE_SLOT(pdev)->hotplug) {
-                qbus_set_hotplug_handler(BUS(sec), NULL);
-                return;
-            }
-
             qbus_set_hotplug_handler(BUS(sec), OBJECT(hotplug_dev));
             /* We don't have to overwrite any other hotplug handler yet */
             assert(QLIST_EMPTY(&sec->child));
@@ -385,6 +361,24 @@ void acpi_pcihp_device_unplug_request_cb(HotplugHandler *hotplug_dev,
     acpi_send_event(DEVICE(hotplug_dev), ACPI_PCI_HOTPLUG_STATUS);
 }
 
+bool acpi_pcihp_is_hotpluggbale_bus(AcpiPciHpState *s, BusState *bus)
+{
+    Object *o = OBJECT(bus->parent);
+
+    if (s->use_acpi_hotplug_bridge &&
+        object_dynamic_cast(o, TYPE_PCI_BRIDGE)) {
+        if (object_dynamic_cast(o, TYPE_PCIE_SLOT) && !PCIE_SLOT(o)->hotplug) {
+            return false;
+        }
+        return true;
+    }
+
+    if (s->use_acpi_root_pci_hotplug) {
+        return true;
+    }
+    return false;
+}
+
 static uint64_t pci_read(void *opaque, hwaddr addr, unsigned int size)
 {
     AcpiPciHpState *s = opaque;

hw/acpi/piix4.c

@@ -404,6 +404,13 @@ static void piix4_device_unplug_cb(HotplugHandler *hotplug_dev,
     }
 }
 
+static bool piix4_is_hotpluggable_bus(HotplugHandler *hotplug_dev,
+                                      BusState *bus)
+{
+    PIIX4PMState *s = PIIX4_PM(hotplug_dev);
+    return acpi_pcihp_is_hotpluggbale_bus(&s->acpi_pci_hotplug, bus);
+}
+
 static void piix4_pm_machine_ready(Notifier *n, void *opaque)
 {
     PIIX4PMState *s = container_of(n, PIIX4PMState, machine_ready);
@@ -644,6 +651,7 @@ static void piix4_pm_class_init(ObjectClass *klass, void *data)
     hc->plug = piix4_device_plug_cb;
     hc->unplug_request = piix4_device_unplug_request_cb;
     hc->unplug = piix4_device_unplug_cb;
+    hc->is_hotpluggable_bus = piix4_is_hotpluggable_bus;
     adevc->ospm_status = piix4_ospm_status;
     adevc->send_event = piix4_send_gpe;
     adevc->madt_cpu = pc_madt_cpu_entry;

hw/isa/lpc_ich9.c

@@ -865,6 +865,7 @@ static void ich9_lpc_class_init(ObjectClass *klass, void *data)
     hc->plug = ich9_pm_device_plug_cb;
     hc->unplug_request = ich9_pm_device_unplug_request_cb;
     hc->unplug = ich9_pm_device_unplug_cb;
+    hc->is_hotpluggable_bus = ich9_pm_is_hotpluggable_bus;
     adevc->ospm_status = ich9_pm_ospm_status;
     adevc->send_event = ich9_send_gpe;
     adevc->madt_cpu = pc_madt_cpu_entry;

include/hw/acpi/ich9.h

@@ -87,6 +87,7 @@ void ich9_pm_device_unplug_request_cb(HotplugHandler *hotplug_dev,
                                       DeviceState *dev, Error **errp);
 void ich9_pm_device_unplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
                               Error **errp);
+bool ich9_pm_is_hotpluggable_bus(HotplugHandler *hotplug_dev, BusState *bus);
 
 void ich9_pm_ospm_status(AcpiDeviceIf *adev, ACPIOSTInfoList ***list);
 #endif /* HW_ACPI_ICH9_H */

include/hw/acpi/pcihp.h

@@ -58,6 +58,7 @@ typedef struct AcpiPciHpState {
 void acpi_pcihp_init(Object *owner, AcpiPciHpState *, PCIBus *root,
                      MemoryRegion *address_space_io, uint16_t io_base);
 
+bool acpi_pcihp_is_hotpluggbale_bus(AcpiPciHpState *s, BusState *bus);
 void acpi_pcihp_device_pre_plug_cb(HotplugHandler *hotplug_dev,
                                    DeviceState *dev, Error **errp);
 void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,