APICs (both local and I/O) are memory mapped devices. The default location for the local APIC is at 0xfee00000 in physical memory. The local APIC will appear in the same place for each processor, but each processor will reference its own APIC。
how can all local apics use the same base address to access their respective registers?
If they use the same physical address, how can each processor reference their own registers like apic id register?