Introduce UnplugCpus() which maps each APIC ID being unplugged onto the hardware ID of the processor and informs PiSmmCpuDxeSmm of removal by calling EFI_SMM_CPU_SERVICE_PROTOCOL.RemoveProcessor(). With this change we handle the first phase of unplug where we collect the CPUs that need to be unplugged and mark them for removal in SMM data structures. Cc: Laszlo Ersek <lersek@redhat.com> Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Ard Biesheuvel <ard.biesheuvel@arm.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Aaron Young <aaron.young@oracle.com> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3132 Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Message-Id: <20210312062656.2477515-5-ankur.a.arora@oracle.com>