Re: [PATCH 3/3] hw/acpi/cpu_hotplug: Convert 'Object *device' -> 'DeviceState *parent'

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Feb 03, 2023 at 05:30:21PM +0100, Philippe Mathieu-Daudé wrote:
> ACPI CPU hotplug parent can't be any QOM object, it must be a QDev.
> Convert AcpiCpuHotplug::device field as QDev to enforce this.
> Rename 'owner' and 'device' variables as 'parent'.
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>


So instead of plain gpe->device we now have OBJECT all over
the place. Why is this an improvement?

> ---
>  hw/acpi/acpi-cpu-hotplug-stub.c |  2 +-
>  hw/acpi/cpu_hotplug.c           | 18 +++++++++---------
>  hw/acpi/ich9.c                  |  5 +++--
>  hw/acpi/piix4.c                 |  2 +-
>  include/hw/acpi/cpu_hotplug.h   |  4 ++--
>  5 files changed, 16 insertions(+), 15 deletions(-)
> 
> diff --git a/hw/acpi/acpi-cpu-hotplug-stub.c b/hw/acpi/acpi-cpu-hotplug-stub.c
> index cbd7a6ec00..0fcc1ec8ea 100644
> --- a/hw/acpi/acpi-cpu-hotplug-stub.c
> +++ b/hw/acpi/acpi-cpu-hotplug-stub.c
> @@ -13,7 +13,7 @@ void acpi_switch_to_modern_cphp(AcpiCpuHotplug *gpe,
>      return;
>  }
>  
> -void legacy_acpi_cpu_hotplug_init(MemoryRegion *container, Object *owner,
> +void legacy_acpi_cpu_hotplug_init(MemoryRegion *container, DeviceState *parent,
>                                    AcpiCpuHotplug *gpe, uint16_t base)
>  {
>      return;
> diff --git a/hw/acpi/cpu_hotplug.c b/hw/acpi/cpu_hotplug.c
> index 636e985c50..b8c9081738 100644
> --- a/hw/acpi/cpu_hotplug.c
> +++ b/hw/acpi/cpu_hotplug.c
> @@ -41,8 +41,8 @@ static void cpu_status_write(void *opaque, hwaddr addr, uint64_t data,
>       */
>      if (addr == 0 && data == 0) {
>          AcpiCpuHotplug *gpe = opaque;
> -        object_property_set_bool(gpe->device, "cpu-hotplug-legacy", false,
> -                                 &error_abort);
> +        object_property_set_bool(OBJECT(gpe->parent), "cpu-hotplug-legacy",
> +                                 false, &error_abort);
>      }
>  }
>  
> @@ -66,8 +66,8 @@ static void acpi_set_cpu_present_bit(AcpiCpuHotplug *gpe, CPUState *cpu)
>  
>      cpu_id = k->get_arch_id(cpu);
>      if ((cpu_id / 8) >= ACPI_GPE_PROC_LEN) {
> -        object_property_set_bool(gpe->device, "cpu-hotplug-legacy", false,
> -                                 &error_abort);
> +        object_property_set_bool(OBJECT(gpe->parent), "cpu-hotplug-legacy",
> +                                 false, &error_abort);
>          return;
>      }
>  
> @@ -81,15 +81,15 @@ void legacy_acpi_cpu_plug_cb(HotplugHandler *hotplug_dev, AcpiCpuHotplug *gpe,
>      acpi_send_event(DEVICE(hotplug_dev), ACPI_CPU_HOTPLUG_STATUS);
>  }
>  
> -void legacy_acpi_cpu_hotplug_init(MemoryRegion *container, Object *owner,
> +void legacy_acpi_cpu_hotplug_init(MemoryRegion *container, DeviceState *parent,
>                                    AcpiCpuHotplug *gpe, uint16_t base)
>  {
>      CPUState *cpu;
>  
> -    memory_region_init_io(&gpe->io, owner, &AcpiCpuHotplug_ops,
> +    memory_region_init_io(&gpe->io, OBJECT(parent), &AcpiCpuHotplug_ops,
>                            gpe, "acpi-cpu-hotplug", ACPI_GPE_PROC_LEN);
>      memory_region_add_subregion(container, base, &gpe->io);
> -    gpe->device = owner;
> +    gpe->parent = parent;
>  
>      CPU_FOREACH(cpu) {
>          acpi_set_cpu_present_bit(gpe, cpu);
> @@ -100,10 +100,10 @@ void acpi_switch_to_modern_cphp(AcpiCpuHotplug *gpe,
>                                  CPUHotplugState *cpuhp_state,
>                                  uint16_t io_port)
>  {
> -    MemoryRegion *container = pci_address_space_io(PCI_DEVICE(gpe->device));
> +    MemoryRegion *container = pci_address_space_io(PCI_DEVICE(gpe->parent));
>  
>      memory_region_del_subregion(container, &gpe->io);
> -    cpu_hotplug_hw_init(container, gpe->device, cpuhp_state, io_port);
> +    cpu_hotplug_hw_init(container, OBJECT(gpe->parent), cpuhp_state, io_port);
>  }
>  
>  void build_legacy_cpu_hotplug_aml(Aml *ctx, MachineState *machine,
> diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
> index 4f8385b894..6c9a737479 100644
> --- a/hw/acpi/ich9.c
> +++ b/hw/acpi/ich9.c
> @@ -197,7 +197,7 @@ static bool vmstate_test_use_cpuhp(void *opaque)
>  static int vmstate_cpuhp_pre_load(void *opaque)
>  {
>      ICH9LPCPMRegs *s = opaque;
> -    Object *obj = OBJECT(s->gpe.device);
> +    Object *obj = OBJECT(s->gpe.parent);
>      object_property_set_bool(obj, "cpu-hotplug-legacy", false, &error_abort);
>      return 0;
>  }
> @@ -338,7 +338,8 @@ void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs *pm,
>      qemu_register_powerdown_notifier(&pm->powerdown_notifier);
>  
>      legacy_acpi_cpu_hotplug_init(pci_address_space_io(lpc_pci),
> -        OBJECT(lpc_pci), &pm->gpe, ICH9_CPU_HOTPLUG_IO_BASE);
> +                                 DEVICE(lpc_pci), &pm->gpe,
> +                                 ICH9_CPU_HOTPLUG_IO_BASE);
>  
>      if (pm->acpi_memory_hotplug.is_enabled) {
>          acpi_memory_hotplug_init(pci_address_space_io(lpc_pci), OBJECT(lpc_pci),
> diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
> index 5595fe5be5..3a61d89f92 100644
> --- a/hw/acpi/piix4.c
> +++ b/hw/acpi/piix4.c
> @@ -571,7 +571,7 @@ static void piix4_acpi_system_hot_add_init(MemoryRegion *container,
>      object_property_add_bool(OBJECT(s), "cpu-hotplug-legacy",
>                               piix4_get_cpu_hotplug_legacy,
>                               piix4_set_cpu_hotplug_legacy);
> -    legacy_acpi_cpu_hotplug_init(container, OBJECT(s), &s->gpe,
> +    legacy_acpi_cpu_hotplug_init(container, DEVICE(s), &s->gpe,
>                                   PIIX4_CPU_HOTPLUG_IO_BASE);
>  
>      if (s->acpi_memory_hotplug.is_enabled) {
> diff --git a/include/hw/acpi/cpu_hotplug.h b/include/hw/acpi/cpu_hotplug.h
> index 5ff24ec417..b2f990f0b8 100644
> --- a/include/hw/acpi/cpu_hotplug.h
> +++ b/include/hw/acpi/cpu_hotplug.h
> @@ -20,7 +20,7 @@
>  #include "hw/acpi/cpu.h"
>  
>  typedef struct AcpiCpuHotplug {
> -    Object *device;
> +    DeviceState *parent;
>      MemoryRegion io;
>      uint8_t sts[ACPI_GPE_PROC_LEN];
>  } AcpiCpuHotplug;
> @@ -28,7 +28,7 @@ typedef struct AcpiCpuHotplug {
>  void legacy_acpi_cpu_plug_cb(HotplugHandler *hotplug_dev, AcpiCpuHotplug *gpe,
>                               DeviceState *dev, Error **errp);
>  
> -void legacy_acpi_cpu_hotplug_init(MemoryRegion *container, Object *owner,
> +void legacy_acpi_cpu_hotplug_init(MemoryRegion *container, DeviceState *parent,
>                                    AcpiCpuHotplug *gpe, uint16_t base);
>  
>  void acpi_switch_to_modern_cphp(AcpiCpuHotplug *gpe,
> -- 
> 2.38.1