> The specification is very clear: these bits are not part of ppn, not > part of the translation target address. The current code is against > the riscv-privilege specification.
If all of the reserved bits are zero then the patch changes nothing. Further the only normative mention of the reserved bits in the spec says they must be: "Bits 63–54 are reserved for future use and must be zeroed by software for forward compatibility." Provided that software follows the spec current QEMU will behave properly. For software that ignores that directive an sets some of those bits, the spec says nothing about what hardware should do, so both the old an the new behavior are fine. Jonathan
