Mismatch in Dependency Between henvcfg and menvcfg in NEMU and XiangShan

[youzi27]

Describe the bug
Hi there,

I noticed a mismatch in the behavior of the dependency between henvcfg and menvcfg in NEMU and XiangShan (XS).

Specifically:

• In NEMU: Bits 4 to 7 of henvcfg are aligned with menvcfg. Modifying menvcfg implicitly updates henvcfg.
• In XS: Bits 4 to 7 of henvcfg are independent of menvcfg. Modifying menvcfg does not affect henvcfg.

To Reproduce

Initial State: Both NEMU and XS initialize menvcfg to 0x80000000000000f0.
After Modification: When menvcfg is modified to 0x0:
In NEMU, henvcfg updates accordingly to reflect the change in menvcfg.
In XS, henvcfg remains unchanged, with bits 4 to 7 unaffected.

Error log or Screenshots

Necessary information on versions

• ready-to-run's NEMU commit id: OpenXiangShan/ready-ro-run@3575e65 (Date: Fri Nov 22 17:06:53 2024 +0800)
• XiangShan commit id: OpenXiangShan/XiangShan@aecf601 (Date: Tue Nov 19 16:16:35 2024 +0800)