[PATCH v5 04/28] hw/i386/pc: Remove PCMachineClass::legacy_cpu_hotplug field

[Zhao Liu <zhao1.liu@intel.com>]

From: Philippe Mathieu-Daudé <philmd@linaro.org>

Now all PC & Q35 machiens are using modern hotplug from the beginning,
and all legacy_cpu_hotplug flags keep false during runtime.

So it's safe to remove legacy_cpu_hotplug flags and related properties,
with unused gpe_cpu field.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
---
Changes since v4:
 * Referring Igor's v5 [*], drop gpe_cpu field and does not only remove
   build_legacy_cpu_hotplug_aml(), but instead remove the entire
   cpu_hotplug.c file in a separate patch.

[*]: https://lore.kernel.org/qemu-devel/20251031142825.179239-1-imammedo@redhat.com/
---
 hw/acpi/ich9.c          | 40 ++++------------------------------------
 hw/acpi/piix4.c         | 40 ++++------------------------------------
 hw/i386/acpi-build.c    |  4 +---
 include/hw/acpi/ich9.h  |  2 --
 include/hw/acpi/piix4.h |  2 --
 include/hw/i386/pc.h    |  3 ---
 6 files changed, 9 insertions(+), 82 deletions(-)

diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
index 54590129c695..f254f3879716 100644
--- a/hw/acpi/ich9.c
+++ b/hw/acpi/ich9.c
@@ -339,26 +339,6 @@ static void ich9_pm_get_gpe0_blk(Object *obj, Visitor *v, const char *name,
     visit_type_uint32(v, name, &value, errp);
 }
 
-static bool ich9_pm_get_cpu_hotplug_legacy(Object *obj, Error **errp)
-{
-    ICH9LPCState *s = ICH9_LPC_DEVICE(obj);
-
-    return s->pm.cpu_hotplug_legacy;
-}
-
-static void ich9_pm_set_cpu_hotplug_legacy(Object *obj, bool value,
-                                           Error **errp)
-{
-    ICH9LPCState *s = ICH9_LPC_DEVICE(obj);
-
-    assert(!value);
-    if (s->pm.cpu_hotplug_legacy && value == false) {
-        acpi_switch_to_modern_cphp(&s->pm.gpe_cpu, &s->pm.cpuhp_state,
-                                   ICH9_CPU_HOTPLUG_IO_BASE);
-    }
-    s->pm.cpu_hotplug_legacy = value;
-}
-
 static bool ich9_pm_get_enable_tco(Object *obj, Error **errp)
 {
     ICH9LPCState *s = ICH9_LPC_DEVICE(obj);
@@ -403,7 +383,6 @@ void ich9_pm_add_properties(Object *obj, ICH9LPCPMRegs *pm)
 {
     static const uint32_t gpe0_len = ICH9_PMIO_GPE0_LEN;
     pm->acpi_memory_hotplug.is_enabled = true;
-    pm->cpu_hotplug_legacy = false;
     pm->disable_s3 = 0;
     pm->disable_s4 = 0;
     pm->s4_val = 2;
@@ -422,9 +401,6 @@ void ich9_pm_add_properties(Object *obj, ICH9LPCPMRegs *pm)
                         NULL, NULL, pm);
     object_property_add_uint32_ptr(obj, ACPI_PM_PROP_GPE0_BLK_LEN,
                                    &gpe0_len, OBJ_PROP_FLAG_READ);
-    object_property_add_bool(obj, "cpu-hotplug-legacy",
-                             ich9_pm_get_cpu_hotplug_legacy,
-                             ich9_pm_set_cpu_hotplug_legacy);
     object_property_add_uint8_ptr(obj, ACPI_PM_PROP_S3_DISABLED,
                                   &pm->disable_s3, OBJ_PROP_FLAG_READWRITE);
     object_property_add_uint8_ptr(obj, ACPI_PM_PROP_S4_DISABLED,
@@ -477,11 +453,7 @@ void ich9_pm_device_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
                                 dev, errp);
         }
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
-        if (lpc->pm.cpu_hotplug_legacy) {
-            legacy_acpi_cpu_plug_cb(hotplug_dev, &lpc->pm.gpe_cpu, dev, errp);
-        } else {
-            acpi_cpu_plug_cb(hotplug_dev, &lpc->pm.cpuhp_state, dev, errp);
-        }
+        acpi_cpu_plug_cb(hotplug_dev, &lpc->pm.cpuhp_state, dev, errp);
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
         acpi_pcihp_device_plug_cb(hotplug_dev, &lpc->pm.acpi_pci_hotplug,
                                   dev, errp);
@@ -500,8 +472,7 @@ void ich9_pm_device_unplug_request_cb(HotplugHandler *hotplug_dev,
         acpi_memory_unplug_request_cb(hotplug_dev,
                                       &lpc->pm.acpi_memory_hotplug, dev,
                                       errp);
-    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU) &&
-               !lpc->pm.cpu_hotplug_legacy) {
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
         uint64_t negotiated = lpc->smi_negotiated_features;
 
         if (negotiated & BIT_ULL(ICH9_LPC_SMI_F_BROADCAST_BIT) &&
@@ -533,8 +504,7 @@ void ich9_pm_device_unplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
 
     if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
         acpi_memory_unplug_cb(&lpc->pm.acpi_memory_hotplug, dev, errp);
-    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU) &&
-               !lpc->pm.cpu_hotplug_legacy) {
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
         acpi_cpu_unplug_cb(&lpc->pm.cpuhp_state, dev, errp);
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
         acpi_pcihp_device_unplug_cb(hotplug_dev, &lpc->pm.acpi_pci_hotplug,
@@ -556,7 +526,5 @@ void ich9_pm_ospm_status(AcpiDeviceIf *adev, ACPIOSTInfoList ***list)
     ICH9LPCState *s = ICH9_LPC_DEVICE(adev);
 
     acpi_memory_ospm_status(&s->pm.acpi_memory_hotplug, list);
-    if (!s->pm.cpu_hotplug_legacy) {
-        acpi_cpu_ospm_status(&s->pm.cpuhp_state, list);
-    }
+    acpi_cpu_ospm_status(&s->pm.cpuhp_state, list);
 }
diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index a7a29b0d09a9..6ad5f1d1c19d 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -336,11 +336,7 @@ static void piix4_device_plug_cb(HotplugHandler *hotplug_dev,
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
         acpi_pcihp_device_plug_cb(hotplug_dev, &s->acpi_pci_hotplug, dev, errp);
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
-        if (s->cpu_hotplug_legacy) {
-            legacy_acpi_cpu_plug_cb(hotplug_dev, &s->gpe_cpu, dev, errp);
-        } else {
-            acpi_cpu_plug_cb(hotplug_dev, &s->cpuhp_state, dev, errp);
-        }
+        acpi_cpu_plug_cb(hotplug_dev, &s->cpuhp_state, dev, errp);
     } else {
         g_assert_not_reached();
     }
@@ -358,8 +354,7 @@ static void piix4_device_unplug_request_cb(HotplugHandler *hotplug_dev,
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
         acpi_pcihp_device_unplug_request_cb(hotplug_dev, &s->acpi_pci_hotplug,
                                             dev, errp);
-    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU) &&
-               !s->cpu_hotplug_legacy) {
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
         acpi_cpu_unplug_request_cb(hotplug_dev, &s->cpuhp_state, dev, errp);
     } else {
         error_setg(errp, "acpi: device unplug request for not supported device"
@@ -378,8 +373,7 @@ static void piix4_device_unplug_cb(HotplugHandler *hotplug_dev,
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
         acpi_pcihp_device_unplug_cb(hotplug_dev, &s->acpi_pci_hotplug, dev,
                                     errp);
-    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU) &&
-               !s->cpu_hotplug_legacy) {
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
         acpi_cpu_unplug_cb(&s->cpuhp_state, dev, errp);
     } else {
         error_setg(errp, "acpi: device unplug for not supported device"
@@ -523,26 +517,6 @@ static const MemoryRegionOps piix4_gpe_ops = {
     .endianness = DEVICE_LITTLE_ENDIAN,
 };
 
-
-static bool piix4_get_cpu_hotplug_legacy(Object *obj, Error **errp)
-{
-    PIIX4PMState *s = PIIX4_PM(obj);
-
-    return s->cpu_hotplug_legacy;
-}
-
-static void piix4_set_cpu_hotplug_legacy(Object *obj, bool value, Error **errp)
-{
-    PIIX4PMState *s = PIIX4_PM(obj);
-
-    assert(!value);
-    if (s->cpu_hotplug_legacy && value == false) {
-        acpi_switch_to_modern_cphp(&s->gpe_cpu, &s->cpuhp_state,
-                                   PIIX4_CPU_HOTPLUG_IO_BASE);
-    }
-    s->cpu_hotplug_legacy = value;
-}
-
 static void piix4_acpi_system_hot_add_init(MemoryRegion *parent,
                                            PCIBus *bus, PIIX4PMState *s)
 {
@@ -558,10 +532,6 @@ static void piix4_acpi_system_hot_add_init(MemoryRegion *parent,
         qbus_set_hotplug_handler(BUS(pci_get_bus(PCI_DEVICE(s))), OBJECT(s));
     }
 
-    s->cpu_hotplug_legacy = false;
-    object_property_add_bool(OBJECT(s), "cpu-hotplug-legacy",
-                             piix4_get_cpu_hotplug_legacy,
-                             piix4_set_cpu_hotplug_legacy);
     cpu_hotplug_hw_init(parent, OBJECT(s), &s->cpuhp_state,
                         PIIX4_CPU_HOTPLUG_IO_BASE);
 
@@ -576,9 +546,7 @@ static void piix4_ospm_status(AcpiDeviceIf *adev, ACPIOSTInfoList ***list)
     PIIX4PMState *s = PIIX4_PM(adev);
 
     acpi_memory_ospm_status(&s->acpi_memory_hotplug, list);
-    if (!s->cpu_hotplug_legacy) {
-        acpi_cpu_ospm_status(&s->cpuhp_state, list);
-    }
+    acpi_cpu_ospm_status(&s->cpuhp_state, list);
 }
 
 static void piix4_send_gpe(AcpiDeviceIf *adev, AcpiEventStatusBits ev)
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 23147ddc25e7..bf7ed2e50837 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -960,9 +960,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
     }
     aml_append(dsdt, scope);
 
-    if (pcmc->legacy_cpu_hotplug) {
-        build_legacy_cpu_hotplug_aml(dsdt, machine, pm->cpu_hp_io_base);
-    } else {
+    {
         CPUHotplugFeatures opts = {
             .acpi_1_compatible = true,
             .smi_path = pm->smi_on_cpuhp ? "\\_SB.PCI0.SMI0.SMIC" : NULL,
diff --git a/include/hw/acpi/ich9.h b/include/hw/acpi/ich9.h
index 245fe08dc245..6a21472eb32e 100644
--- a/include/hw/acpi/ich9.h
+++ b/include/hw/acpi/ich9.h
@@ -53,8 +53,6 @@ typedef struct ICH9LPCPMRegs {
     uint32_t pm_io_base;
     Notifier powerdown_notifier;
 
-    bool cpu_hotplug_legacy;
-    AcpiCpuHotplug gpe_cpu;
     CPUHotplugState cpuhp_state;
 
     bool keep_pci_slot_hpc;
diff --git a/include/hw/acpi/piix4.h b/include/hw/acpi/piix4.h
index eb1c122d8069..e075f0cbeaf1 100644
--- a/include/hw/acpi/piix4.h
+++ b/include/hw/acpi/piix4.h
@@ -63,8 +63,6 @@ struct PIIX4PMState {
     uint8_t disable_s4;
     uint8_t s4_val;
 
-    bool cpu_hotplug_legacy;
-    AcpiCpuHotplug gpe_cpu;
     CPUHotplugState cpuhp_state;
 
     MemHotplugState acpi_memory_hotplug;
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index e83157ab358f..698e3fb84af0 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -110,9 +110,6 @@ struct PCMachineClass {
     bool enforce_amd_1tb_hole;
     bool isa_bios_alias;
 
-    /* generate legacy CPU hotplug AML */
-    bool legacy_cpu_hotplug;
-
     /* use PVH to load kernels that support this feature */
     bool pvh_enabled;
 
-- 
2.34.1