sync_qemu_models_i386: Copy signatures from base model

The signatures in the CPU map are used for matching physical CPUs and
thus we need to cover all possible real world variants we know about.
When adding a new version of an existing CPU model, we should copy the
signature(s) of the existing model rather than replacing it with the
signature that QEMU uses.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

src/cpu_map/sync_qemu_models_i386.py

@@ -429,7 +429,30 @@ def transform(item):
     raise RuntimeError("unexpected item type")
 
 
-def expand_model(model):
+def get_signature(outdir, model):
+    file = os.path.join(outdir, f"x86_{model}.xml")
+
+    if not os.path.isfile(file):
+        return None
+
+    xml = lxml.etree.parse(file)
+
+    signature = []
+    for sig in xml.xpath("//signature"):
+        attr = sig.attrib
+        family = attr["family"]
+        model = attr["model"]
+        if "stepping" in attr:
+            stepping = attr["stepping"]
+        else:
+            stepping = None
+
+        signature.append((family, model, stepping))
+
+    return signature
+
+
+def expand_model(outdir, model):
     """Expand a qemu cpu model description that has its feature split up into
     different fields and may have differing versions into several libvirt-
     friendly cpu models."""
@@ -438,11 +461,14 @@ def expand_model(model):
         "name": model.pop(".name"),
         "vendor": translate_vendor(model.pop(".vendor")),
         "features": set(),
-        "extra": dict()}
+        "extra": dict(),
+        "signature": list(),
+    }
 
     if ".family" in model and ".model" in model:
-        result["family"] = model.pop(".family")
-        result["model"] = model.pop(".model")
+        result["signature"].append((model.pop(".family"),
+                                    model.pop(".model"),
+                                    None))
 
     for k in [k for k in model if k.startswith(".features")]:
         v = model.pop(k)
@@ -470,6 +496,10 @@ def expand_model(model):
         if not alias and ver == 1:
             alias = name
 
+            sig = get_signature(outdir, name)
+            if sig:
+                result["signature"] = sig
+
         props = version.pop(".props", dict())
         for k, v in props:
             if k not in ("model-id", "stepping", "model"):
@@ -524,7 +554,11 @@ def output_model(f, extra, model):
     if "alias" in model:
         f.write(f"    <model name='{model['alias']}'/>\n")
     else:
-        f.write(f"    <signature family='{model['family']}' model='{model['model']}'/>\n")
+        for sig_family, sig_model, sig_stepping in model['signature']:
+            f.write(f"    <signature family='{sig_family}' model='{sig_model}'")
+            if sig_stepping:
+                f.write(f" stepping='{sig_stepping}'")
+            f.write("/>\n")
         f.write(f"    <vendor name='{model['vendor']}'/>\n")
 
     for feature in sorted(model["features"]):
@@ -600,7 +634,7 @@ def main():
 
     models = list()
     for model in models_json:
-        models.extend(expand_model(model))
+        models.extend(expand_model(args.outdir, model))
 
     files = dict()