>For RV32, values with satp[31] clear and satp[30:0] non-zero are reserved. I propose that values with satp[31] clear and satp[30:29]=0x3 be defined as Custom.
Are 7 bits enough , for ASID?
It depends on how you are using them. For x86-64, Linux actually only uses 4 ASID bits (out of the 12 available) because it assigns them per-core and recycles them aggressively. However, if you instead try to have globally unique ASIDs then you might need far more than 7 bits.
