Re: [PATCH v3] target/arm: implement FEAT_E2H0

[Richard Henderson]

On 2/6/26 07:02, Alex Bennée wrote:

@@ -3817,10 +3821,15 @@ static void do_hcr_write(CPUARMState *env, uint64_t 
value, uint64_t valid_mask)
      /* Clear RES0 bits.  */
      value &= valid_mask;

- /* RW is RAO/WI if EL1 is AArch64 only */

-    if (arm_feature(env, ARM_FEATURE_AARCH64) &&
-        !cpu_isar_feature(aa64_aa32_el1, cpu)) {
-        value |= HCR_RW;
+    if (arm_feature(env, ARM_FEATURE_AARCH64)) {
+        /* RW is RAO/WI if EL1 is AArch64 only */
+        if (!cpu_isar_feature(aa64_aa32_el1, cpu)) {
+            value |= HCR_RW;
+        }
+        /* Strictly E2H is RES1 unless FEAT_E2H0 relaxes the requirement */
+        if (!cpu_isar_feature(aa64_e2h0, cpu)) {
+            value |= HCR_E2H;
+        }
      }

Reset value of hcr_el2 should have E2H set too.
I think you want something like cpacr_reset().


r~