cpu: Introduce virCPUValidateFeatures

This new API may be used to check whether all features used in a CPU
definition are valid (e.g., libvirt knows their name, their policy is
supported, etc.). Leaving this API unimplemented in an arch subdriver
means libvirt does not restrict CPU features usable on the associated
architectures.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

src/cpu/cpu.c

@@ -1076,3 +1076,32 @@ virCPUCopyMigratable(virArch arch,
     else
         return virCPUDefCopy(cpu);
 }
+
+
+/**
+ * virCPUValidateFeatures:
+ *
+ * @arch: CPU architecture
+ * @cpu: CPU definition to be checked
+ *
+ * Checks whether all CPU features specified in @cpu are valid.
+ *
+ * Returns 0 on success (all features are valid), -1 on error.
+ */
+int
+virCPUValidateFeatures(virArch arch,
+                       virCPUDefPtr cpu)
+{
+    struct cpuArchDriver *driver;
+
+    VIR_DEBUG("arch=%s, cpu=%p, nfeatures=%zu",
+              virArchToString(arch), cpu, cpu->nfeatures);
+
+    if (!(driver = cpuGetSubDriver(arch)))
+        return -1;
+
+    if (driver->validateFeatures)
+        return driver->validateFeatures(cpu);
+    else
+        return 0;
+}

src/cpu/cpu.h

@@ -121,6 +121,9 @@ typedef int
 typedef virCPUDefPtr
 (*virCPUArchCopyMigratable)(virCPUDefPtr cpu);
 
+typedef int
+(*virCPUArchValidateFeatures)(virCPUDefPtr cpu);
+
 struct cpuArchDriver {
     const char *name;
     const virArch *arch;
@@ -142,6 +145,7 @@ struct cpuArchDriver {
     virCPUArchConvertLegacy convertLegacy;
     virCPUArchExpandFeatures expandFeatures;
     virCPUArchCopyMigratable copyMigratable;
+    virCPUArchValidateFeatures validateFeatures;
 };
 
 
@@ -258,6 +262,11 @@ virCPUDefPtr
 virCPUCopyMigratable(virArch arch,
                      virCPUDefPtr cpu);
 
+int
+virCPUValidateFeatures(virArch arch,
+                       virCPUDefPtr cpu)
+    ATTRIBUTE_NONNULL(2);
+
 /* virCPUDataFormat and virCPUDataParse are implemented for unit tests only and
  * have no real-life usage
  */

src/libvirt_private.syms

@@ -1097,6 +1097,7 @@ virCPUProbeHost;
 virCPUTranslate;
 virCPUUpdate;
 virCPUUpdateLive;
+virCPUValidateFeatures;
 
 
 # cpu/cpu_x86.h