1 files changed, 58 insertions, 0 deletions
diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
index afa3ec5f4d..b64d06afc9 100644
--- a/hw/acpi/pcihp.c
+++ b/hw/acpi/pcihp.c
@@ -39,6 +39,7 @@
 #include "migration/vmstate.h"
 #include "qapi/error.h"
 #include "qom/qom-qobject.h"
+#include "qobject/qnum.h"
 #include "trace.h"
 
 #define ACPI_PCIHP_SIZE 0x0018
@@ -703,6 +704,63 @@ void build_append_pcihp_resources(Aml *scope /* \\_SB.PCI0 */,
     aml_append(scope, dev);
 }
 
+bool build_append_notification_callback(Aml *parent_scope, const PCIBus *bus)
+{
+    Aml *method;
+    PCIBus *sec;
+    QObject *bsel;
+    int nr_notifiers = 0;
+    GQueue *pcnt_bus_list = g_queue_new();
+
+    QLIST_FOREACH(sec, &bus->child, sibling) {
+        Aml *br_scope = aml_scope("S%.02X", sec->parent_dev->devfn);
+        if (pci_bus_is_root(sec)) {
+            continue;
+        }
+        nr_notifiers = nr_notifiers +
+                       build_append_notification_callback(br_scope, sec);
+        /*
+         * add new child scope to parent
+         * and keep track of bus that have PCNT,
+         * bus list is used later to call children PCNTs from this level PCNT
+         */
+        if (nr_notifiers) {
+            g_queue_push_tail(pcnt_bus_list, 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));
+
+        aml_append(method, aml_store(aml_int(bsel_val), aml_name("BNUM")));
+        aml_append(method, aml_call2("DVNT", aml_name("PCIU"),
+                                     aml_int(1))); /* Device Check */
+        aml_append(method, aml_call2("DVNT", aml_name("PCID"),
+                                     aml_int(3))); /* Eject Request */
+        nr_notifiers++;
+    }
+
+    /* Notify about child bus events in any case */
+    while ((sec = g_queue_pop_head(pcnt_bus_list))) {
+        aml_append(method, aml_name("^S%.02X.PCNT", sec->parent_dev->devfn));
+    }
+
+    aml_append(parent_scope, method);
+    qobject_unref(bsel);
+    g_queue_free(pcnt_bus_list);
+    return !!nr_notifiers;
+}
+
 const VMStateDescription vmstate_acpi_pcihp_pci_status = {
     .name = "acpi_pcihp_pci_status",
     .version_id = 1,