From: Bruno Sa <[email protected]>

On RV32, STCE/ADUE/PBMTE/DTE are implemented in henvcfgh. A write to
henvcfg should therefore only update the low 32 bits of env->henvcfg.

The current write_henvcfg() path overwrites env->henvcfg with the
low-half value and clears any bits previously written via henvcfgh.

Preserve the upper 32 bits on RV32 henvcfg writes and keep the existing
RV64 behaviour unchanged.

Signed-off-by: Bruno Sa <[email protected]>
Reviewed-by: Alistair Francis <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Alistair Francis <[email protected]>
---
 target/riscv/csr.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index a75281539b..cfd076b368 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -3353,7 +3353,15 @@ static RISCVException write_henvcfg(CPURISCVState *env, 
int csrno,
         }
     }
 
-    env->henvcfg = val & mask;
+    if (riscv_cpu_mxl(env) == MXL_RV32) {
+        /*
+         * RV32 stores STCE/ADUE/PBMTE/DTE in henvcfgh, so a low-half henvcfg
+         * write must not clobber the upper 32 bits.
+         */
+        env->henvcfg = (env->henvcfg & ~0xFFFFFFFFULL) | (val & mask);
+    } else {
+        env->henvcfg = val & mask;
+    }
     if ((env->henvcfg & HENVCFG_DTE) == 0) {
         env->vsstatus &= ~MSTATUS_SDT;
     }
-- 
2.53.0


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