ACPI is required to interface QEMU with the guest. Roughly falls into below
cases,

1. Convey the possible vCPUs config at the machine init time to the guest
   using various DSDT tables like MADT etc.
2. Convey vCPU hotplug events to guest(using GED)
3. Assist in evaluation of various ACPI methods(like _EVT, _STA, _OST, _EJ0,
   _MAT etc.)
4. Provides ACPI CPU hotplug state and 12 Byte memory mapped vCPU hotplug
   control register interface to the OSPM/guest corresponding to each possible
   vcpu. The register interface consists of various R/W fields and their
   handling operations. These are called when ever register fields or memory
   regions are accessed (i.e. read or written) by OSPM when ever it evaluates
   various ACPI methods.

Note: lot of this framework code is inherited from the changes already done for
      x86 but still some minor changes are required to make it compatible with
      ARM64.)

Enable the ACPI support switch for vCPU hotplug feature. Actual ACPI changes
required will follow in subsequent patches.

Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
---
 hw/arm/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
index eac5070514..77cdbc5c27 100644
--- a/hw/arm/Kconfig
+++ b/hw/arm/Kconfig
@@ -33,6 +33,7 @@ config ARM_VIRT
     select ACPI_HW_REDUCED
     select ACPI_APEI
     select ACPI_VIOT
+    select ACPI_CPU_HOTPLUG
     select VIRTIO_MEM_SUPPORTED
     select ACPI_CXL
     select ACPI_HMAT
-- 
2.34.1