Probe QEMU directly for machine aliases if not found in capabilties

Not all possible emulators are actually in the capabilities, so if we
don't find the supplied emulator we should probe it directly for machine
types.

* src/qemu_driver.c: add qemudCanonicalizeMachineDirect() to directly
  probe an emulator for the canonical machine type

src/qemu_conf.c

@@ -401,7 +401,7 @@ error:
     return -1;
 }
 
-static int
+int
 qemudProbeMachineTypes(const char *binary,
                        virCapsGuestMachinePtr **machines,
                        int *nmachines)

src/qemu_conf.h

@@ -168,6 +168,10 @@ int         qemuBuildNicStr             (virConnectPtr conn,
 int         qemuAssignNetNames          (virDomainDefPtr def,
                                          virDomainNetDefPtr net);
 
+int         qemudProbeMachineTypes      (const char *binary,
+                                         virCapsGuestMachinePtr **machines,
+                                         int *nmachines);
+
 virDomainDefPtr qemuParseCommandLine(virConnectPtr conn,
                                      virCapsPtr caps,
                                      const char **progenv,

src/qemu_driver.c

@@ -4286,6 +4286,34 @@ qemudCanonicalizeMachineFromInfo(virDomainDefPtr def,
     return 0;
 }
 
+static int
+qemudCanonicalizeMachineDirect(virDomainDefPtr def, char **canonical)
+{
+    virCapsGuestMachinePtr *machines = NULL;
+    int i, nmachines = 0;
+
+    if (qemudProbeMachineTypes(def->emulator, &machines, &nmachines) < 0) {
+        virReportOOMError(NULL);
+        return -1;
+    }
+
+    for (i = 0; i < nmachines; i++) {
+        if (!machines[i]->canonical)
+            continue;
+
+        if (strcmp(def->os.machine, machines[i]->name) != 0)
+            continue;
+
+        *canonical = machines[i]->canonical;
+        machines[i]->canonical = NULL;
+        break;
+    }
+
+    virCapabilitiesFreeMachines(machines, nmachines);
+
+    return 0;
+}
+
 static int
 qemudCanonicalizeMachine(virConnectPtr conn, virDomainDefPtr def)
 {
@@ -4323,6 +4351,10 @@ qemudCanonicalizeMachine(virConnectPtr conn, virDomainDefPtr def)
             goto out;
         }
     }
+
+    if (qemudCanonicalizeMachineDirect(def, &canonical) < 0)
+        return -1;
+
 out:
     if (canonical) {
         VIR_FREE(def->os.machine);