target/riscv: Check SUM in the correct register

Table 9.5 "Effect of MPRV..." specifies that MPV=1 uses VS-level
vsstatus.SUM instead of HS-level sstatus.SUM.

For HLV/HSV instructions, the HS-level register does not apply, but
the VS-level register presumably does, though this is not mentioned
explicitly in the manual.  However, it matches the behavior for MPV.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Tested-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-Id: <20230325105429.1142530-18-richard.henderson@linaro.org>
Message-Id: <20230412114333.118895-18-richard.henderson@linaro.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu_helper.c

@@ -42,11 +42,16 @@ int riscv_cpu_mmu_index(CPURISCVState *env, bool ifetch)
 
     /* All priv -> mmu_idx mapping are here */
     if (!ifetch) {
-        if (mode == PRV_M && get_field(env->mstatus, MSTATUS_MPRV)) {
+        uint64_t status = env->mstatus;
+
+        if (mode == PRV_M && get_field(status, MSTATUS_MPRV)) {
             mode = get_field(env->mstatus, MSTATUS_MPP);
             virt = get_field(env->mstatus, MSTATUS_MPV);
+            if (virt) {
+                status = env->vsstatus;
+            }
         }
-        if (mode == PRV_S && get_field(env->mstatus, MSTATUS_SUM)) {
+        if (mode == PRV_S && get_field(status, MSTATUS_SUM)) {
             mode = MMUIdx_S_SUM;
         }
     }
@@ -826,8 +831,7 @@ static int get_physical_address(CPURISCVState *env, hwaddr *physical,
         }
         widened = 2;
     }
-    /* status.SUM will be ignored if execute on background */
-    sum = mmuidx_sum(mmu_idx) || use_background || is_debug;
+    sum = mmuidx_sum(mmu_idx) || is_debug;
     switch (vm) {
     case VM_1_10_SV32:
       levels = 2; ptidxbits = 10; ptesize = 4; break;

target/riscv/op_helper.c

@@ -437,7 +437,11 @@ static int check_access_hlsv(CPURISCVState *env, bool x, uintptr_t ra)
         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, ra);
     }
 
-    return get_field(env->hstatus, HSTATUS_SPVP) | MMU_2STAGE_BIT;
+    int mode = get_field(env->hstatus, HSTATUS_SPVP);
+    if (!x && mode == PRV_S && get_field(env->vsstatus, MSTATUS_SUM)) {
+        mode = MMUIdx_S_SUM;
+    }
+    return mode | MMU_2STAGE_BIT;
 }
 
 target_ulong helper_hyp_hlv_bu(CPURISCVState *env, target_ulong addr)