pc: use new CPU hotplug interface since 2.7 machine type

For compatibility reasons PC/Q35 will start with legacy
CPU hotplug interface by default but with new CPU hotplug
AML code since 2.7 machine type. That way legacy firmware
that doesn't use QEMU generated ACPI tables will be
able to continue using legacy CPU hotplug interface.

While new machine type, with firmware supporting QEMU
provided ACPI tables, will generate new CPU hotplug AML,
which will switch to new CPU hotplug interface when
guest OS executes its _INI method on ACPI tables
loading.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index e35a446..20e5b49 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -33,6 +33,7 @@
 #include "hw/timer/hpet.h"
 #include "hw/acpi/acpi-defs.h"
 #include "hw/acpi/acpi.h"
+#include "hw/acpi/cpu.h"
 #include "hw/nvram/fw_cfg.h"
 #include "hw/acpi/bios-linker-loader.h"
 #include "hw/loader.h"
@@ -1895,6 +1896,7 @@
     GPtrArray *mem_ranges = g_ptr_array_new_with_free_func(crs_range_free);
     GPtrArray *io_ranges = g_ptr_array_new_with_free_func(crs_range_free);
     PCMachineState *pcms = PC_MACHINE(machine);
+    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(machine);
     uint32_t nr_mem = machine->ram_slots;
     int root_bus_limit = 0xFF;
     PCIBus *bus = NULL;
@@ -1950,7 +1952,15 @@
         build_q35_pci0_int(dsdt);
     }
 
-    build_legacy_cpu_hotplug_aml(dsdt, machine, pm->cpu_hp_io_base);
+    if (pcmc->legacy_cpu_hotplug) {
+        build_legacy_cpu_hotplug_aml(dsdt, machine, pm->cpu_hp_io_base);
+    } else {
+        CPUHotplugFeatures opts = {
+            .apci_1_compatible = true, .has_legacy_cphp = true
+        };
+        build_cpus_aml(dsdt, machine, opts, pm->cpu_hp_io_base,
+                       "\\_SB.PCI0", "\\_GPE._E02");
+    }
     build_memory_hotplug_aml(dsdt, nr_mem, pm->mem_hp_io_base,
                              pm->mem_hp_io_len);