net/vmnet: use availability check at runtime

MAC_OS_X_VERSION_MIN_REQUIRED is set at compile time so this means that when
we target an older macOS version, it disables the newer features. With a
runtime check, we can selectively disable newer API features.

net/vmnet-bridged.m

@@ -88,15 +88,16 @@ static bool validate_options(const Netdev *netdev, Error **errp)
         return false;
     }
 
-#if !defined(MAC_OS_VERSION_11_0) || \
-    MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_VERSION_11_0
-    if (options->has_isolated) {
-        error_setg(errp,
-                   "vmnet-bridged.isolated feature is "
-                   "unavailable: outdated vmnet.framework API");
-        return false;
+    if (__builtin_available(macOS 11, *)) {
+        // clang requires a true branch
+    } else {
+        if (options->has_isolated) {
+            error_setg(errp,
+                       "vmnet-bridged.isolated feature is "
+                       "unavailable: outdated vmnet.framework API");
+            return false;
+        }
     }
-#endif
     return true;
 }
 
@@ -115,12 +116,12 @@ static xpc_object_t build_if_desc(const Netdev *netdev)
                               vmnet_shared_interface_name_key,
                               options->ifname);
 
-#if defined(MAC_OS_VERSION_11_0) && \
-    MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_VERSION_11_0
-    xpc_dictionary_set_bool(if_desc,
-                            vmnet_enable_isolation_key,
-                            options->isolated);
-#endif
+    if (__builtin_available(macOS 11, *)) {
+        xpc_dictionary_set_bool(if_desc,
+                                vmnet_enable_isolation_key,
+                                options->isolated);
+    }
+
     return if_desc;
 }
 

net/vmnet-common.m

@@ -47,7 +47,7 @@
     case VMNET_TOO_MANY_PACKETS:
         return "packet count exceeds limit";
 #if defined(MAC_OS_VERSION_11_0) && \
-    MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_VERSION_11_0
+    MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_VERSION_11_0
     case VMNET_SHARING_SERVICE_BUSY:
         return "conflict, sharing service is in use";
 #endif

net/vmnet-host.c

@@ -22,31 +22,29 @@ static bool validate_options(const Netdev *netdev, Error **errp)
 {
     const NetdevVmnetHostOptions *options = &(netdev->u.vmnet_host);
 
-#if defined(MAC_OS_VERSION_11_0) && \
-    MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_VERSION_11_0
-
-    QemuUUID net_uuid;
-    if (options->has_net_uuid &&
-        qemu_uuid_parse(options->net_uuid, &net_uuid) < 0) {
-        error_setg(errp, "Invalid UUID provided in 'net-uuid'");
-        return false;
-    }
-#else
-    if (options->has_isolated) {
-        error_setg(errp,
-                   "vmnet-host.isolated feature is "
-                   "unavailable: outdated vmnet.framework API");
-        return false;
+    if (__builtin_available(macOS 11, *)) {
+        QemuUUID net_uuid;
+        if (options->has_net_uuid &&
+            qemu_uuid_parse(options->net_uuid, &net_uuid) < 0) {
+            error_setg(errp, "Invalid UUID provided in 'net-uuid'");
+            return false;
+        }
+    } else {
+        if (options->has_isolated) {
+            error_setg(errp,
+                       "vmnet-host.isolated feature is "
+                       "unavailable: outdated vmnet.framework API");
+            return false;
+        }
+
+        if (options->has_net_uuid) {
+            error_setg(errp,
+                       "vmnet-host.net-uuid feature is "
+                       "unavailable: outdated vmnet.framework API");
+            return false;
+        }
     }
 
-    if (options->has_net_uuid) {
-        error_setg(errp,
-                   "vmnet-host.net-uuid feature is "
-                   "unavailable: outdated vmnet.framework API");
-        return false;
-    }
-#endif
-
     if ((options->has_start_address ||
          options->has_end_address ||
          options->has_subnet_mask) &&
@@ -71,21 +69,19 @@ static xpc_object_t build_if_desc(const Netdev *netdev)
                               vmnet_operation_mode_key,
                               VMNET_HOST_MODE);
 
-#if defined(MAC_OS_VERSION_11_0) && \
-    MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_VERSION_11_0
-
-    xpc_dictionary_set_bool(if_desc,
-                            vmnet_enable_isolation_key,
-                            options->isolated);
-
-    QemuUUID net_uuid;
-    if (options->has_net_uuid) {
-        qemu_uuid_parse(options->net_uuid, &net_uuid);
-        xpc_dictionary_set_uuid(if_desc,
-                                vmnet_network_identifier_key,
-                                net_uuid.data);
+    if (__builtin_available(macOS 11, *)) {
+        xpc_dictionary_set_bool(if_desc,
+                                vmnet_enable_isolation_key,
+                                options->isolated);
+
+        QemuUUID net_uuid;
+        if (options->has_net_uuid) {
+            qemu_uuid_parse(options->net_uuid, &net_uuid);
+            xpc_dictionary_set_uuid(if_desc,
+                                    vmnet_network_identifier_key,
+                                    net_uuid.data);
+        }
     }
-#endif
 
     if (options->has_start_address) {
         xpc_dictionary_set_string(if_desc,

net/vmnet-shared.c

@@ -21,15 +21,16 @@ static bool validate_options(const Netdev *netdev, Error **errp)
 {
     const NetdevVmnetSharedOptions *options = &(netdev->u.vmnet_shared);
 
-#if !defined(MAC_OS_VERSION_11_0) || \
-    MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_VERSION_11_0
-    if (options->has_isolated) {
-        error_setg(errp,
-                   "vmnet-shared.isolated feature is "
-                   "unavailable: outdated vmnet.framework API");
-        return false;
+    if (__builtin_available(macOS 11, *)) {
+        // clang requires a true branch
+    } else {
+        if (options->has_isolated) {
+            error_setg(errp,
+                       "vmnet-shared.isolated feature is "
+                       "unavailable: outdated vmnet.framework API");
+            return false;
+        }
     }
-#endif
 
     if ((options->has_start_address ||
          options->has_end_address ||
@@ -76,14 +77,13 @@ static xpc_object_t build_if_desc(const Netdev *netdev)
                                   options->subnet_mask);
     }
 
-#if defined(MAC_OS_VERSION_11_0) && \
-    MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_VERSION_11_0
-    xpc_dictionary_set_bool(
-        if_desc,
-        vmnet_enable_isolation_key,
-        options->isolated
-    );
-#endif
+    if (__builtin_available(macOS 11, *)) {
+        xpc_dictionary_set_bool(
+            if_desc,
+            vmnet_enable_isolation_key,
+            options->isolated
+        );
+    }
 
     return if_desc;
 }