driver: Introduce global driver feature flag handling function

The 'virDrvFeature' has a combination of features which are asserted by
the specific driver and features which are actually global.

In many cases the implementation was cargo-culted into newer drivers
without re-assesing whether it makes sense.

This patch introduces a global function which will specifically handle
these global flags and defer the rest to the driver.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>

src/ch/ch_driver.c

@@ -919,9 +919,14 @@ static int
 chConnectSupportsFeature(virConnectPtr conn,
                          int feature)
 {
+    int supported;
+
     if (virConnectSupportsFeatureEnsureACL(conn) < 0)
         return -1;
 
+    if (virDriverFeatureIsGlobal(feature, &supported))
+        return supported;
+
     switch ((virDrvFeature) feature) {
         case VIR_DRV_FEATURE_TYPED_PARAM_STRING:
         case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:

src/driver.c

@@ -316,3 +316,44 @@ virConnectValidateURIPath(const char *uriPath,
 
     return true;
 }
+
+
+/**
+ * virDriverFeatureIsGlobal:
+ * @feat: a VIR_DRV_FEATURE
+ * @supported: If a feature is globally handled
+ *
+ * Certain driver feature flags are really not for individual drivers to decide
+ * whether they implement them or not, but are rather global based on e.g.
+ * whether the RPC protocol supports it.
+ *
+ * This function returns 'true' and fills @supported if a feature is a global
+ * feature and the individual driver implementations don't decide whether
+ * they support it or not.
+ */
+bool
+virDriverFeatureIsGlobal(virDrvFeature feat,
+                         int *supported G_GNUC_UNUSED)
+
+{
+    switch (feat) {
+    case VIR_DRV_FEATURE_TYPED_PARAM_STRING:
+    case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:
+    case VIR_DRV_FEATURE_FD_PASSING:
+    case VIR_DRV_FEATURE_MIGRATION_V2:
+    case VIR_DRV_FEATURE_MIGRATION_V3:
+    case VIR_DRV_FEATURE_MIGRATION_P2P:
+    case VIR_DRV_FEATURE_MIGRATE_CHANGE_PROTECTION:
+    case VIR_DRV_FEATURE_XML_MIGRATABLE:
+    case VIR_DRV_FEATURE_MIGRATION_OFFLINE:
+    case VIR_DRV_FEATURE_MIGRATION_PARAMS:
+    case VIR_DRV_FEATURE_MIGRATION_DIRECT:
+    case VIR_DRV_FEATURE_MIGRATION_V1:
+    case VIR_DRV_FEATURE_PROGRAM_KEEPALIVE:
+    case VIR_DRV_FEATURE_REMOTE:
+    case VIR_DRV_FEATURE_REMOTE_CLOSE_CALLBACK:
+    case VIR_DRV_FEATURE_REMOTE_EVENT_CALLBACK:
+    default:
+        return false;
+    }
+}

src/driver.h

@@ -131,3 +131,6 @@ int virSetConnectStorage(virConnectPtr conn);
 bool virConnectValidateURIPath(const char *uriPath,
                                const char *entityName,
                                bool privileged);
+
+bool virDriverFeatureIsGlobal(virDrvFeature feat,
+                              int *supported);

src/esx/esx_driver.c

@@ -1018,6 +1018,10 @@ esxConnectSupportsFeature(virConnectPtr conn, int feature)
 {
     esxPrivate *priv = conn->privateData;
     esxVI_Boolean supportsVMotion = esxVI_Boolean_Undefined;
+    int supported;
+
+    if (virDriverFeatureIsGlobal(feature, &supported))
+        return supported;
 
     switch ((virDrvFeature) feature) {
       case VIR_DRV_FEATURE_MIGRATION_V1:

src/libvirt_private.syms

@@ -1528,6 +1528,7 @@ virStreamClass;
 
 # driver.h
 virConnectValidateURIPath;
+virDriverFeatureIsGlobal;
 virDriverShouldAutostart;
 virGetConnectInterface;
 virGetConnectNetwork;

src/libxl/libxl_driver.c

@@ -5697,9 +5697,14 @@ libxlConnectListAllDomains(virConnectPtr conn,
 static int
 libxlConnectSupportsFeature(virConnectPtr conn, int feature)
 {
+    int supported;
+
     if (virConnectSupportsFeatureEnsureACL(conn) < 0)
         return -1;
 
+    if (virDriverFeatureIsGlobal(feature, &supported))
+        return supported;
+
     switch ((virDrvFeature) feature) {
     case VIR_DRV_FEATURE_MIGRATION_V3:
     case VIR_DRV_FEATURE_TYPED_PARAM_STRING:

src/lxc/lxc_driver.c

@@ -1618,9 +1618,14 @@ static int lxcStateCleanup(void)
 static int
 lxcConnectSupportsFeature(virConnectPtr conn, int feature)
 {
+    int supported;
+
     if (virConnectSupportsFeatureEnsureACL(conn) < 0)
         return -1;
 
+    if (virDriverFeatureIsGlobal(feature, &supported))
+        return supported;
+
     switch ((virDrvFeature) feature) {
     case VIR_DRV_FEATURE_TYPED_PARAM_STRING:
     case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:

src/network/bridge_driver.c

@@ -857,9 +857,14 @@ static int networkConnectIsAlive(virConnectPtr conn G_GNUC_UNUSED)
 static int
 networkConnectSupportsFeature(virConnectPtr conn, int feature)
 {
+    int supported;
+
     if (virConnectSupportsFeatureEnsureACL(conn) < 0)
         return -1;
 
+    if (virDriverFeatureIsGlobal(feature, &supported))
+        return supported;
+
     switch ((virDrvFeature) feature) {
     case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:
         return 1;

src/openvz/openvz_driver.c

@@ -1938,6 +1938,11 @@ openvzNodeGetCPUMap(virConnectPtr conn G_GNUC_UNUSED,
 static int
 openvzConnectSupportsFeature(virConnectPtr conn G_GNUC_UNUSED, int feature)
 {
+    int supported;
+
+    if (virDriverFeatureIsGlobal(feature, &supported))
+        return supported;
+
     switch ((virDrvFeature) feature) {
     case VIR_DRV_FEATURE_MIGRATION_PARAMS:
     case VIR_DRV_FEATURE_MIGRATION_V3:

src/qemu/qemu_driver.c

@@ -1173,9 +1173,14 @@ static int qemuConnectClose(virConnectPtr conn)
 static int
 qemuConnectSupportsFeature(virConnectPtr conn, int feature)
 {
+    int supported;
+
     if (virConnectSupportsFeatureEnsureACL(conn) < 0)
         return -1;
 
+    if (virDriverFeatureIsGlobal(feature, &supported))
+        return supported;
+
     switch ((virDrvFeature) feature) {
     case VIR_DRV_FEATURE_MIGRATION_V2:
     case VIR_DRV_FEATURE_MIGRATION_V3:

src/test/test_driver.c

@@ -1667,6 +1667,11 @@ static int
 testConnectSupportsFeature(virConnectPtr conn G_GNUC_UNUSED,
                            int feature)
 {
+    int supported;
+
+    if (virDriverFeatureIsGlobal(feature, &supported))
+        return supported;
+
     switch ((virDrvFeature) feature) {
     case VIR_DRV_FEATURE_TYPED_PARAM_STRING:
     case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:

src/vz/vz_driver.c

@@ -3006,9 +3006,14 @@ vzDomainMigratePrepare3Params(virConnectPtr conn,
 static int
 vzConnectSupportsFeature(virConnectPtr conn G_GNUC_UNUSED, int feature)
 {
+    int supported;
+
     if (virConnectSupportsFeatureEnsureACL(conn) < 0)
         return -1;
 
+    if (virDriverFeatureIsGlobal(feature, &supported))
+        return supported;
+
     switch ((virDrvFeature) feature) {
     case VIR_DRV_FEATURE_MIGRATION_PARAMS:
     case VIR_DRV_FEATURE_MIGRATION_P2P: