FEAT_SME_FA64 allows Streaming SVE code to access the whole
SVE instruction set; it requires FEAT_SVE to be present. If
we have a CPU with SME but not SVE, squash the FA64 bit in
arm_cpu_sme_finalize().

This doesn't have any effect at the moment because we don't
let the user create an SME-without-SVE CPU, but we are about
to lift that restriction.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/cpu64.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index a9c1e60c95..c0447c8d54 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -385,6 +385,11 @@ void arm_cpu_sme_finalize(ARMCPU *cpu, Error **errp)
         /* SME2 or better */
         FIELD_DP64_IDREG(&cpu->isar, ID_AA64PFR1, SME, 2);
     }
+
+    if (!cpu_isar_feature(aa64_sve, cpu)) {
+        /* FEAT_SME_FA64 requires SVE, not just SME */
+        FIELD_DP64_IDREG(&cpu->isar, ID_AA64SMFR0, FA64, 0);
+    }
 }
 
 static bool cpu_arm_get_sme(Object *obj, Error **errp)
-- 
2.43.0