Location of the SMRAM
• Specified in the SMBASE register of the CPU. This register cannot be
accessed at all. Its content is copied in the SMRAM saved state map and can
only be changed when the CPU state is restored.
• This is useful for multi-CPU systems
CPU 在進入和離開 SMM 時會去存取 State Save Area 的資料(CPU 內部暫存器的值)
這部分是CPU 去做的，不是SMI Handler 做的!!
SMI HANDLER EXECUTION ENVIRONMENT
After saving the current context of the processor, the processor initializes
its core registers to the values. Upon entering SMM, the PE and PG flags
in control register CR0 are cleared, which places the processor is in an environment
similar to real-address mode.
in control register CR0 are cleared, which places the processor is in an environment
similar to real-address mode.
