pc: add acpi-device link to PCMachineState

the link will used later to access device implementing
ACPI functions instead of adhoc lookup in QOM tree.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/acpi/piix4.c

@@ -483,13 +483,17 @@ Object *piix4_pm_find(void)
 
 I2CBus *piix4_pm_init(PCIBus *bus, int devfn, uint32_t smb_io_base,
                       qemu_irq sci_irq, qemu_irq smi_irq,
-                      int kvm_enabled, FWCfgState *fw_cfg)
+                      int kvm_enabled, FWCfgState *fw_cfg,
+                      DeviceState **piix4_pm)
 {
     DeviceState *dev;
     PIIX4PMState *s;
 
     dev = DEVICE(pci_create(bus, devfn, TYPE_PIIX4_PM));
     qdev_prop_set_uint32(dev, "smb_io_base", smb_io_base);
+    if (piix4_pm) {
+        *piix4_pm = dev;
+    }
 
     s = PIIX4_PM(dev);
     s->irq = sci_irq;

hw/i386/pc_piix.c

@@ -74,6 +74,7 @@ static void pc_init1(MachineState *machine,
                      int pci_enabled,
                      int kvmclock_enabled)
 {
+    PCMachineState *pc_machine = PC_MACHINE(machine);
     MemoryRegion *system_memory = get_system_memory();
     MemoryRegion *system_io = get_system_io();
     int i;
@@ -246,14 +247,23 @@ static void pc_init1(MachineState *machine,
     }
 
     if (pci_enabled && acpi_enabled) {
+        DeviceState *piix4_pm;
         I2CBus *smbus;
 
         smi_irq = qemu_allocate_irqs(pc_acpi_smi_interrupt, first_cpu, 1);
         /* TODO: Populate SPD eeprom data.  */
         smbus = piix4_pm_init(pci_bus, piix3_devfn + 3, 0xb100,
                               gsi[9], *smi_irq,
-                              kvm_enabled(), fw_cfg);
+                              kvm_enabled(), fw_cfg, &piix4_pm);
         smbus_eeprom_init(smbus, 8, NULL, 0);
+
+        object_property_add_link(OBJECT(machine), PC_MACHINE_ACPI_DEVICE_PROP,
+                                 TYPE_HOTPLUG_HANDLER,
+                                 (Object **)&pc_machine->acpi_dev,
+                                 object_property_allow_set_link,
+                                 OBJ_PROP_LINK_UNREF_ON_RELEASE, &error_abort);
+        object_property_set_link(OBJECT(machine), OBJECT(piix4_pm),
+                                 PC_MACHINE_ACPI_DEVICE_PROP, &error_abort);
     }
 
     if (pci_enabled) {

hw/i386/pc_q35.c

@@ -62,6 +62,7 @@ static bool has_reserved_memory = true;
 /* PC hardware initialisation */
 static void pc_q35_init(MachineState *machine)
 {
+    PCMachineState *pc_machine = PC_MACHINE(machine);
     ram_addr_t below_4g_mem_size, above_4g_mem_size;
     Q35PCIHost *q35_host;
     PCIHostState *phb;
@@ -178,6 +179,15 @@ static void pc_q35_init(MachineState *machine)
     lpc = pci_create_simple_multifunction(host_bus, PCI_DEVFN(ICH9_LPC_DEV,
                                           ICH9_LPC_FUNC), true,
                                           TYPE_ICH9_LPC_DEVICE);
+
+    object_property_add_link(OBJECT(machine), PC_MACHINE_ACPI_DEVICE_PROP,
+                             TYPE_HOTPLUG_HANDLER,
+                             (Object **)&pc_machine->acpi_dev,
+                             object_property_allow_set_link,
+                             OBJ_PROP_LINK_UNREF_ON_RELEASE, &error_abort);
+    object_property_set_link(OBJECT(machine), OBJECT(lpc),
+                             PC_MACHINE_ACPI_DEVICE_PROP, &error_abort);
+
     ich9_lpc = ICH9_LPC_DEVICE(lpc);
     ich9_lpc->pic = gsi;
     ich9_lpc->ioapic = gsi_state->ioapic_irq;

hw/mips/mips_malta.c

@@ -1104,7 +1104,7 @@ void mips_malta_init(MachineState *machine)
     pci_piix4_ide_init(pci_bus, hd, piix4_devfn + 1);
     pci_create_simple(pci_bus, piix4_devfn + 2, "piix4-usb-uhci");
     smbus = piix4_pm_init(pci_bus, piix4_devfn + 3, 0x1100,
-                          isa_get_irq(NULL, 9), NULL, 0, NULL);
+                          isa_get_irq(NULL, 9), NULL, 0, NULL, NULL);
     smbus_eeprom_init(smbus, 8, smbus_eeprom_buf, smbus_eeprom_size);
     g_free(smbus_eeprom_buf);
     pit = pit_init(isa_bus, 0x40, 0, NULL);

include/hw/i386/pc.h

@@ -21,6 +21,7 @@
  * @hotplug_memory_base: address in guest RAM address space where hotplug memory
  * address space begins.
  * @hotplug_memory: hotplug memory addess space container
+ * @acpi_dev: link to ACPI PM device that performs ACPI hotplug handling
  */
 struct PCMachineState {
     /*< private >*/
@@ -29,8 +30,12 @@ struct PCMachineState {
     /* <public> */
     ram_addr_t hotplug_memory_base;
     MemoryRegion hotplug_memory;
+
+    HotplugHandler *acpi_dev;
 };
 
+#define PC_MACHINE_ACPI_DEVICE_PROP "acpi-device"
+
 /**
  * PCMachineClass:
  * @get_hotplug_handler: pointer to parent class callback @get_hotplug_handler
@@ -210,7 +215,8 @@ void ioapic_init_gsi(GSIState *gsi_state, const char *parent_name);
 
 I2CBus *piix4_pm_init(PCIBus *bus, int devfn, uint32_t smb_io_base,
                       qemu_irq sci_irq, qemu_irq smi_irq,
-                      int kvm_enabled, FWCfgState *fw_cfg);
+                      int kvm_enabled, FWCfgState *fw_cfg,
+                      DeviceState **piix4_pm);
 void piix4_smbus_register_device(SMBusDevice *dev, uint8_t addr);
 
 /* hpet.c */