target/riscv: fix address translation in hypervisor mode

[zqb-all]

address translation don't need to care hstatus.HU

[en-sc]

@zqb-all, can you please expand on the motivation for the patch?

I don't know much about virtualization, but AFAIU from [21.2.10. Hypervisor Guest Address Translation and Protection (hgatp) Register] of The RISC-V Instruction Set Manual: Volume II: Privileged Architecture version 20250508

The hgatp register is considered active for the purposes of the address-translation algorithm unless the effective privilege mode is U and hstatus.HU=0.

The code you are deleting is correct.

What am I missing?

[zqb-all]

Field HU (Hypervisor in U-mode) controls whether the virtual-machine
load/store instructions, HLV, HLVX, and HSV, can be used also in U-mode.
When HU=1, these instructions can be executed in U-mode the same as in
HS-mode. When HU=0, all hypervisor instructions cause an
illegal-instruction exception in U-mode.

hstatus.HU only affects the behavior of the cpu when executing the virtual-machine load/store instructions HLV, HLVX, and HSV. When we do address translation in openocd, we should behave like a cpu doing normal load/store instructions

The hgatp register is considered active for the purposes of the
address-translation algorithm unless the effective privilege mode is U
and hstatus.HU=0.

active , means that the hardware mmu address translation may use this register. However, even if the register is not active, it does not mean that the address translation is not working.
In U mode, most of the time address translation is done by reading satp registers to do VA(virtual address) -> PA(Physical Addresses) . Only when cpu executes instructions such as HLV, register hgatp and vsatp are required (active) to do GVA(Guest Virtual Address)->GPA(Guest Physical Address)->SPA(Supervisor Physical Address)

Back to this patch, when we go into this if (vmode), it must be VU or VS, not U mode. And VU and VS do not need to consider hstatus.HU. To ensure that the address translation in VU mode works properly, we need to delete these code.