virtio: introduce virtio_legacy_is_cross_endian()

This helper will be used by vhost and tap to detect cross-endianness in
the legacy virtio case.

Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/include/hw/virtio/virtio-access.h b/include/hw/virtio/virtio-access.h
index ee28c21fefeda40ff8ff2d199842bcc4e7f7ecdb..cee5dd70c9970a14e951ddb204a14400d253b3da 100644 (file)
--- a/include/hw/virtio/virtio-access.h
+++ b/include/hw/virtio/virtio-access.h
@@ -32,6 +32,19 @@ static inline bool virtio_access_is_big_endian(VirtIODevice *vdev)
 #endif
 }
 
+static inline bool virtio_legacy_is_cross_endian(VirtIODevice *vdev)
+{
+#ifdef TARGET_IS_BIENDIAN
+#ifdef HOST_WORDS_BIGENDIAN
+    return !virtio_is_big_endian(vdev);
+#else
+    return virtio_is_big_endian(vdev);
+#endif
+#else
+    return false;
+#endif
+}
+
 static inline uint16_t virtio_lduw_phys(VirtIODevice *vdev, hwaddr pa)
 {
     if (virtio_access_is_big_endian(vdev)) {