target/s390x: report deprecated-props in cpu-model-expansion reply

Retain a list of deprecated features disjoint from any particular
CPU model. A query-cpu-model-expansion reply will now provide a list of
properties (i.e. features) that are flagged as deprecated. Example:

    {
      "return": {
        "model": {
          "name": "z14.2-base",
          "deprecated-props": [
            "bpb",
            "csske"
          ],
          "props": {
            "pfmfi": false,
            "exrl": true,
            ...a lot more props...
            "skey": false,
            "vxpdeh2": false
          }
        }
      }
    }

It is recommended that s390 guests operate with these features
explicitly disabled to ensure compatibility with future hardware.

Signed-off-by: Collin Walling <walling@linux.ibm.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-ID: <20240429191059.11806-2-walling@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/target/s390x/cpu_features.c b/target/s390x/cpu_features.c
index d28eb65845..efafc9711c 100644
--- a/target/s390x/cpu_features.c
+++ b/target/s390x/cpu_features.c
@@ -212,6 +212,20 @@ void s390_feat_bitmap_to_ascii(const S390FeatBitmap features, void *opaque,
     };
 }
 
+void s390_get_deprecated_features(S390FeatBitmap features)
+{
+    static const int feats[] = {
+         /* CSSKE is deprecated on newer generations */
+         S390_FEAT_CONDITIONAL_SSKE,
+         S390_FEAT_BPB,
+    };
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(feats); i++) {
+        set_bit(feats[i], features);
+    }
+}
+
 #define FEAT_GROUP_INIT(_name, _group, _desc)        \
     {                                                \
         .name = _name,                               \