cpu: Reimplement PowerPCDecode

PowerPC CPUs are either identical or incompatible and thus we just need
to look up the right model for given PVR without pretending we have
several candidates which we may choose from.

The function is also renamed as ppcDecode to match other functions in
PowerPC CPU driver.

src/cpu/cpu_powerpc.c

@@ -70,16 +70,16 @@ struct ppc_map {
 };
 
 static int
-ConvertModelVendorFromPVR(char ***model,
-                          char ***vendor,
+ConvertModelVendorFromPVR(char **model,
+                          char **vendor,
                           uint32_t pvr)
 {
     int i;
 
     for (i = 0; cpu_defs[i].name; i++) {
         if (cpu_defs[i].pvr == pvr) {
-            **model = strdup(cpu_defs[i].name);
-            **vendor = strdup(cpu_defs[i].vendor);
+            *model = strdup(cpu_defs[i].name);
+            *vendor = strdup(cpu_defs[i].vendor);
             return 0;
         }
     }
@@ -107,24 +107,6 @@ ConvertPVRFromModel(const char *model,
     return -1;
 }
 
-static int
-cpuMatch(const union cpuData *data,
-         char **cpu_model,
-         char **cpu_vendor,
-         const struct ppc_model *model)
-{
-    int ret = 0;
-
-    ret = ConvertModelVendorFromPVR(&cpu_model, &cpu_vendor, data->ppc.pvr);
-
-    if (STREQ(model->name, *cpu_model) &&
-        STREQ(model->vendor->name, *cpu_vendor))
-        ret = 1;
-
-    return ret;
-}
-
-
 static struct ppc_model *
 ppcModelNew(void)
 {
@@ -372,102 +354,41 @@ ppcCompare(virCPUDefPtr host,
 }
 
 static int
-PowerPCDecode(virCPUDefPtr cpu,
+ppcDecode(virCPUDefPtr cpu,
           const union cpuData *data,
           const char **models,
           unsigned int nmodels,
-          const char *preferred)
+          const char *preferred ATTRIBUTE_UNUSED)
 {
     int ret = -1;
     struct ppc_map *map;
-    const struct ppc_model *candidate;
-    virCPUDefPtr cpuCandidate;
-    virCPUDefPtr cpuModel = NULL;
     char *cpu_vendor = NULL;
     char *cpu_model = NULL;
-    unsigned int i;
 
     if (data == NULL || (map = ppcLoadMap()) == NULL)
         return -1;
 
-    candidate = map->models;
-
-    while (candidate != NULL) {
-        bool allowed = (models == NULL);
-
-        for (i = 0; i < nmodels; i++) {
-            if (models && models[i] && STREQ(models[i], candidate->name)) {
-                allowed = true;
-                break;
-            }
-        }
+    if (ConvertModelVendorFromPVR(&cpu_model, &cpu_vendor, data->ppc.pvr) < 0)
+        goto cleanup;
 
-        if (!allowed) {
-            if (preferred && STREQ(candidate->name, preferred)) {
-                if (cpu->fallback != VIR_CPU_FALLBACK_ALLOW) {
-                    virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
-                                   _("CPU model %s is not supported by hypervisor"),
-                                   preferred);
-                    goto out;
-                } else {
-                    VIR_WARN("Preferred CPU model %s not allowed by"
-                             " hypervisor; closest supported model will be"
-                             " used", preferred);
-                }
-            } else {
-                VIR_DEBUG("CPU model %s not allowed by hypervisor; ignoring",
-                          candidate->name);
-            }
-            goto next;
-        }
-
-        if (VIR_ALLOC(cpuCandidate) < 0) {
-            virReportOOMError();
-            goto out;
-        }
-
-        cpuCandidate->model = strdup(candidate->name);
-        cpuCandidate->vendor = strdup(candidate->vendor->name);
-
-        if (preferred && STREQ(cpuCandidate->model, preferred)) {
-            virCPUDefFree(cpuModel);
-            cpuModel = cpuCandidate;
-            break;
-        }
-
-        ret = cpuMatch(data, &cpu_model, &cpu_vendor, candidate);
-        if (ret < 0) {
-            VIR_FREE(cpuCandidate);
-            goto out;
-        } else if (ret == 1) {
-            cpuCandidate->model = cpu_model;
-            cpuCandidate->vendor = cpu_vendor;
-            virCPUDefFree(cpuModel);
-            cpuModel = cpuCandidate;
-            break;
-        }
-
-        virCPUDefFree(cpuCandidate);
-
-    next:
-        candidate = candidate->next;
-    }
-
-    if (cpuModel == NULL) {
-        virReportError(VIR_ERR_INTERNAL_ERROR,
-                       "%s", _("Cannot find suitable CPU model for given data"));
-        goto out;
+    if (!cpuModelIsAllowed(cpu_model, models, nmodels)) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                       _("CPU model %s is not supported by hypervisor"),
+                       cpu_model);
+        goto cleanup;
     }
 
-    cpu->model = cpuModel->model;
-    cpu->vendor = cpuModel->vendor;
-    VIR_FREE(cpuModel);
+    cpu->model = cpu_model;
+    cpu->vendor = cpu_vendor;
+    cpu_model = NULL;
+    cpu_vendor = NULL;
 
     ret = 0;
 
-out:
+cleanup:
+    VIR_FREE(cpu_model);
+    VIR_FREE(cpu_vendor);
     ppcMapFree(map);
-    virCPUDefFree(cpuModel);
 
     return ret;
 }
@@ -600,7 +521,7 @@ struct cpuArchDriver cpuDriverPowerPC = {
     .arch = archs,
     .narch = ARRAY_CARDINALITY(archs),
     .compare    = ppcCompare,
-    .decode     = PowerPCDecode,
+    .decode     = ppcDecode,
     .encode     = NULL,
     .free       = PowerPCDataFree,
 #if defined(__powerpc__) || defined(__powerpc64__)