pcihp: compose PCNT callchain right before its user _GPE._E01

it's a stepping stone to making build_append_pci_bus_devices() suitable
for AcpiDevAmlIfClass:build_dev_aml callback and lets further simplify
it by separating PCNT generation from slots descriptions.

It also makes PCNT callchain ASL much more readable since callchain
not longer cluttered by slots descriptors.

Plus, move will let next patch easily drop empty PCNT (pc/q35)
when there is nothing hotpluggable.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20230112140312.3096331-22-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 30 insertions, 2 deletions

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 27f2cc4..d434ad9 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -388,7 +388,6 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
 {
     Aml *dev, *notify_method = NULL, *method;
     QObject *bsel;
-    PCIBus *sec;
     int devfn;
 
     bsel = object_property_get_qobject(OBJECT(bus), ACPI_PCIHP_PROP_BSEL, NULL);
@@ -494,12 +493,35 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
         aml_append(parent_scope, notify_method);
     }
 
+    qobject_unref(bsel);
+}
+
+static void build_append_notfication_callback(Aml *parent_scope,
+                                              const PCIBus *bus)
+{
+    Aml *method;
+    PCIBus *sec;
+    QObject *bsel;
+
+    QLIST_FOREACH(sec, &bus->child, sibling) {
+        Aml *br_scope = aml_scope("S%.02X", sec->parent_dev->devfn);
+        if (pci_bus_is_root(sec) ||
+            !object_property_find(OBJECT(sec), ACPI_PCIHP_PROP_BSEL)) {
+            continue;
+        }
+        build_append_notfication_callback(br_scope, sec);
+        aml_append(parent_scope, br_scope);
+    }
+
     /*
      * Append PCNT method to notify about events on local and child buses.
+     * ps: hostbridge might not have hotplug (bsel) enabled but might have
+     * child bridges that do have bsel.
      */
     method = aml_method("PCNT", 0, AML_NOTSERIALIZED);
 
     /* If bus supports hotplug select it and notify about local events */
+    bsel = object_property_get_qobject(OBJECT(bus), ACPI_PCIHP_PROP_BSEL, NULL);
     if (bsel) {
         uint64_t bsel_val = qnum_get_uint(qobject_to(QNum, bsel));
 
@@ -521,7 +543,6 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
     }
 
     aml_append(parent_scope, method);
-
     qobject_unref(bsel);
 }
 
@@ -1721,6 +1742,13 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
     aml_append(dsdt, sb_scope);
 
     if (pm->pcihp_bridge_en || pm->pcihp_root_en) {
+        Object *pci_host = acpi_get_i386_pci_host();
+        PCIBus *bus = PCI_HOST_BRIDGE(pci_host)->bus;
+
+        scope = aml_scope("\\_SB.PCI0");
+        build_append_notfication_callback(scope, bus);
+        aml_append(dsdt, scope);
+
         scope =  aml_scope("_GPE");
         {
             method = aml_method("_E01", 0, AML_NOTSERIALIZED);