[Stable-7.2.19 12/15] target/arm: Fix sve_access_check for SME

[Michael Tokarev]

From: Richard Henderson <richard.hender...@linaro.org>

Do not assume SME implies SVE.  Ensure that the non-streaming
check is present along the SME path, since it is not implied
by sme_*_enabled_check.

Cc: qemu-sta...@nongnu.org
Reviewed-by: Peter Maydell <peter.mayd...@linaro.org>
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
Message-id: 20250704142112.1018902-3-richard.hender...@linaro.org
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
(cherry picked from commit b4b2e070f41dd8774a70c6186141678558d79a38)
(Mjt: compensate for target/arm/translate-a64.c => target/arm/tcg/
 files move by v7.2.0-1632-gf0984d4040c3)
Signed-off-by: Michael Tokarev <m...@tls.msk.ru>

diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 74237ef6f9..7210a9cc4d 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -1187,11 +1187,8 @@ static bool fp_access_check_only(DisasContext *s)
     return true;
 }
 
-static bool fp_access_check(DisasContext *s)
+static bool nonstreaming_check(DisasContext *s)
 {
-    if (!fp_access_check_only(s)) {
-        return false;
-    }
     if (s->sme_trap_nonstreaming && s->is_nonstreaming) {
         gen_exception_insn(s, 0, EXCP_UDEF,
                            syn_smetrap(SME_ET_Streaming, false));
@@ -1200,6 +1197,11 @@ static bool fp_access_check(DisasContext *s)
     return true;
 }
 
+static bool fp_access_check(DisasContext *s)
+{
+    return fp_access_check_only(s) && nonstreaming_check(s);
+}
+
 /*
  * Check that SVE access is enabled.  If it is, return true.
  * If not, emit code to generate an appropriate exception and return false.
@@ -1207,14 +1209,24 @@ static bool fp_access_check(DisasContext *s)
  */
 bool sve_access_check(DisasContext *s)
 {
-    if (s->pstate_sm || !dc_isar_feature(aa64_sve, s)) {
+    if (dc_isar_feature(aa64_sme, s)) {
         bool ret;
 
-        assert(dc_isar_feature(aa64_sme, s));
-        ret = sme_sm_enabled_check(s);
+        if (s->pstate_sm) {
+            ret = sme_enabled_check(s);
+        } else if (dc_isar_feature(aa64_sve, s)) {
+            goto continue_sve;
+        } else {
+            ret = sme_sm_enabled_check(s);
+        }
+        if (ret) {
+            ret = nonstreaming_check(s);
+        }
         s->sve_access_checked = (ret ? 1 : -1);
         return ret;
     }
+
+ continue_sve:
     if (s->sve_excp_el) {
         /* Assert that we only raise one exception per instruction. */
         assert(!s->sve_access_checked);
-- 
2.47.2