target/arm: Implement SMSTART, SMSTOP

These two instructions are aliases of MSR (immediate).
Use the two helpers to properly implement svcr_write.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220620175235.60881-11-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 5cf4a283ba..c050ebe005 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -1762,6 +1762,30 @@ static void handle_msr_i(DisasContext *s, uint32_t insn,
         }
         break;
 
+    case 0x1b: /* SVCR* */
+        if (!dc_isar_feature(aa64_sme, s) || crm < 2 || crm > 7) {
+            goto do_unallocated;
+        }
+        if (sme_access_check(s)) {
+            bool i = crm & 1;
+            bool changed = false;
+
+            if ((crm & 2) && i != s->pstate_sm) {
+                gen_helper_set_pstate_sm(cpu_env, tcg_constant_i32(i));
+                changed = true;
+            }
+            if ((crm & 4) && i != s->pstate_za) {
+                gen_helper_set_pstate_za(cpu_env, tcg_constant_i32(i));
+                changed = true;
+            }
+            if (changed) {
+                gen_rebuild_hflags(s);
+            } else {
+                s->base.is_jmp = DISAS_NEXT;
+            }
+        }
+        break;
+
     default:
     do_unallocated:
         unallocated_encoding(s);