On 24/08/2026 14:04, Daniel P. Berrangé wrote:

On Fri, Aug 21, 2026 at 12:14:26PM +0100, Mark Cave-Ayland wrote:
Move the ACPI_PCIHP_PROP_BSEL property to the PCIBus object and update all
callers accordingly.

Since the existing logic checks for the existence of the ACPI_PCIHP_PROP_BSEL
property to enable the relevant ACPI changes, set the type of the underlying
variable to uint32_t with a default value of UINT32_MAX indicating that the
property has not been set.

Signed-off-by: Mark Cave-Ayland <[email protected]>
Reviewed-by: Marc-André Lureau <[email protected]>
---
  include/hw/pci/pci_bus.h |  2 ++
  hw/acpi/pci-bridge.c     |  9 ++++++++-
  hw/acpi/pcihp.c          | 30 ++++++++++++++----------------
  hw/arm/virt-acpi-build.c |  7 ++++++-
  hw/i386/acpi-build.c     |  7 ++++++-
  hw/pci/pci.c             |  7 +++++++
  6 files changed, 43 insertions(+), 19 deletions(-)

diff --git a/include/hw/pci/pci_bus.h b/include/hw/pci/pci_bus.h
index c738446788..7ecb23d13c 100644
--- a/include/hw/pci/pci_bus.h
+++ b/include/hw/pci/pci_bus.h
@@ -56,6 +56,8 @@ struct PCIBus {
      int *irq_count;
Notifier machine_done;
+
+    uint32_t acpi_pcihp_bsel_val;
  };
static inline bool pci_bus_is_cxl(PCIBus *bus)
diff --git a/hw/acpi/pci-bridge.c b/hw/acpi/pci-bridge.c
index 394a919479..1bfc5431f2 100644
--- a/hw/acpi/pci-bridge.c
+++ b/hw/acpi/pci-bridge.c
@@ -23,6 +23,8 @@ void build_pci_bridge_aml(AcpiDevAmlIf *adev, Aml *scope)
if (!DEVICE(br)->hotplugged) {
          PCIBus *sec_bus = pci_bridge_get_sec_bus(br);
+        Error *local_err = NULL;
+        uint32_t bsel;
build_append_pci_bus_devices(scope, sec_bus); @@ -30,9 +32,14 @@ void build_pci_bridge_aml(AcpiDevAmlIf *adev, Aml *scope)
           * generate hotplug slots descriptors if
           * bridge has ACPI PCI hotplug attached,
           */
-        if (object_property_find(OBJECT(sec_bus), ACPI_PCIHP_PROP_BSEL)) {
+        bsel = object_property_get_uint(OBJECT(sec_bus), ACPI_PCIHP_PROP_BSEL,
+                                        &local_err);
+
+        if (local_err == NULL && bsel != UINT32_MAX) {
              build_append_pcihp_slots(scope, sec_bus);
          }
+
+        error_free(local_err);

IIUC, in this new approach the property should always exist and so I'd
expect object_property_get_uint to always succeed.

IOW, is something stopping us using &error_abort and merely checking

   if (bsel != UINT32_MAX)

?

I think that would work, although in the back of my mind I have a memory that we should try avoiding error_abort where at all possible.

Markus, any thoughts/comments on error_abort usage?

      }
  }
diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
index a91f523c93..b26ddf0a26 100644
--- a/hw/acpi/pcihp.c
+++ b/hw/acpi/pcihp.c
@@ -58,7 +58,7 @@ typedef struct AcpiPciHpFind {
  static int acpi_pcihp_get_bsel(PCIBus *bus)
  {
      Error *local_err = NULL;
-    uint64_t bsel = object_property_get_uint(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
+    uint32_t bsel = object_property_get_uint(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
                                               &local_err);
if (local_err || bsel >= ACPI_PCIHP_MAX_HOTPLUG_BUS) {
@@ -78,18 +78,14 @@ typedef struct {
  static void *acpi_set_bsel(PCIBus *bus, void *opaque)
  {
      BSELInfo *info = opaque;
-    unsigned *bus_bsel;
      DeviceState *br = bus->qbus.parent;
      bool is_bridge = IS_PCI_BRIDGE(br);
/* hotplugged bridges can't be described in ACPI ignore them */
      if (qbus_is_hotpluggable(BUS(bus))) {
          if (!is_bridge || (!br->hotplugged && info->has_bridge_hotplug)) {
-            bus_bsel = g_malloc(sizeof *bus_bsel);
-
-            *bus_bsel = info->bsel_alloc++;
-            object_property_add_uint32_ptr(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
-                                           bus_bsel, OBJ_PROP_FLAG_READ);
+            object_property_set_uint(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
+                                     info->bsel_alloc++, NULL);
          }
      }
@@ -730,14 +726,16 @@ bool build_append_notification_callback(Aml *parent_scope, const PCIBus *bus)
      /* 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++;
+        uint32_t bsel_val = qnum_get_uint(qobject_to(QNum, bsel));
+
+        if (bsel_val != UINT32_MAX) {
+            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 */
@@ -848,7 +846,7 @@ void build_append_pcihp_slots(Aml *parent_scope, PCIBus 
*bus)
      Aml *dev, *notify_method = NULL, *method;
      QObject *bsel = object_property_get_qobject(OBJECT(bus),
                          ACPI_PCIHP_PROP_BSEL, NULL);
-    uint64_t bsel_val = qnum_get_uint(qobject_to(QNum, bsel));
+    uint32_t bsel_val = qnum_get_uint(qobject_to(QNum, bsel));
      qobject_unref(bsel);
aml_append(parent_scope, aml_name_decl("BSEL", aml_int(bsel_val)));
diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index f6386088b6..7ba7b38773 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -1207,6 +1207,8 @@ build_dsdt(GArray *table_data, BIOSLinker *linker, 
VirtMachineState *vms)
      AcpiTable table = { .sig = "DSDT", .rev = 2, .oem_id = vms->oem_id,
                          .oem_table_id = vms->oem_table_id };
      Aml *pci0_scope;
+    Error *local_err = NULL;
+    uint32_t bsel;
acpi_table_begin(&table, table_data);
      dsdt = init_aml_allocator();
@@ -1269,9 +1271,12 @@ build_dsdt(GArray *table_data, BIOSLinker *linker, 
VirtMachineState *vms)
aml_append(pci0_scope, build_pci_bridge_edsm());
      build_append_pci_bus_devices(pci0_scope, vms->bus);
-    if (object_property_find(OBJECT(vms->bus), ACPI_PCIHP_PROP_BSEL)) {
+    bsel = object_property_get_uint(OBJECT(vms->bus), ACPI_PCIHP_PROP_BSEL,
+                                    &local_err);
+    if (local_err == NULL && bsel != UINT32_MAX) {
          build_append_pcihp_slots(pci0_scope, vms->bus);
      }
+    error_free(local_err);
if (vms->acpi_dev) {
          bool acpi_pcihp;
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 8837b69687..cc0b6e5633 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -1198,15 +1198,20 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
      sb_scope = aml_scope("\\_SB");
      {
          Object *pci_host = acpi_get_i386_pci_host();
+        Error *local_err = NULL;
+        uint32_t bsel;
if (pci_host) {
              PCIBus *pbus = PCI_HOST_BRIDGE(pci_host)->bus;
              Aml *ascope = aml_scope("PCI0");
              /* Scan all PCI buses. Generate tables to support hotplug. */
              build_append_pci_bus_devices(ascope, pbus);
-            if (object_property_find(OBJECT(pbus), ACPI_PCIHP_PROP_BSEL)) {
+            bsel = object_property_get_uint(OBJECT(pbus), ACPI_PCIHP_PROP_BSEL,
+                                            &local_err);
+            if (local_err == NULL && bsel != UINT32_MAX) {
                  build_append_pcihp_slots(ascope, pbus);
              }
+            error_free(local_err);
              aml_append(sb_scope, ascope);
          }
      }
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index d3191609e2..e8e8a3b767 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -25,6 +25,7 @@
  #include "qemu/osdep.h"
  #include "qemu/datadir.h"
  #include "qemu/units.h"
+#include "hw/acpi/pcihp.h"
  #include "hw/core/irq.h"
  #include "hw/pci/pci.h"
  #include "hw/pci/pci_bridge.h"
@@ -187,6 +188,8 @@ static void pci_bus_realize(BusState *qbus, Error **errp)
      bus->machine_done.notify = pcibus_machine_done;
      qemu_add_machine_init_done_notifier(&bus->machine_done);
+ bus->acpi_pcihp_bsel_val = UINT32_MAX;
+
      vmstate_register_any(NULL, &vmstate_pcibus, bus);
  }
@@ -302,6 +305,10 @@ static void pci_bus_class_init(ObjectClass *klass, const void *data)
      pbc->numa_node = pcibus_numa_node;
fwgc->get_data = pci_bus_fw_cfg_gen_data;
+
+    object_class_property_add_uint32_ptr(klass, ACPI_PCIHP_PROP_BSEL,
+                                         offsetof(PCIBus, acpi_pcihp_bsel_val),
+                                         OBJ_PROP_FLAG_READWRITE);
  }
static const TypeInfo pci_bus_info = {
--
2.43.0

ATB,

Mark.


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