configure: add CONFIG_VIRTIO_BLK_DATA_PLANE

The virtio-blk-data-plane feature only works with Linux AIO.  Therefore
add a ./configure option and necessary checks to implement this
dependency.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

configure

@@ -223,6 +223,7 @@ libiscsi=""
 coroutine=""
 seccomp=""
 glusterfs=""
+virtio_blk_data_plane=""
 
 # parse CC options first
 for opt do
@@ -882,6 +883,10 @@ for opt do
   ;;
   --enable-glusterfs) glusterfs="yes"
   ;;
+  --disable-virtio-blk-data-plane) virtio_blk_data_plane="no"
+  ;;
+  --enable-virtio-blk-data-plane) virtio_blk_data_plane="yes"
+  ;;
   *) echo "ERROR: unknown option $opt"; show_help="yes"
   ;;
   esac
@@ -2273,6 +2278,17 @@ EOF
   fi
 fi
 
+##########################################
+# adjust virtio-blk-data-plane based on linux-aio
+
+if test "$virtio_blk_data_plane" = "yes" -a \
+	"$linux_aio" != "yes" ; then
+  echo "Error: virtio-blk-data-plane requires Linux AIO, please try --enable-linux-aio"
+  exit 1
+elif test -z "$virtio_blk_data_plane" ; then
+  virtio_blk_data_plane=$linux_aio
+fi
+
 ##########################################
 # attr probe
 
@@ -3289,6 +3305,7 @@ echo "build guest agent $guest_agent"
 echo "seccomp support   $seccomp"
 echo "coroutine backend $coroutine_backend"
 echo "GlusterFS support $glusterfs"
+echo "virtio-blk-data-plane $virtio_blk_data_plane"
 
 if test "$sdl_too_old" = "yes"; then
 echo "-> Your SDL version is too old - please upgrade to have SDL support"
@@ -3634,6 +3651,10 @@ if test "$glusterfs" = "yes" ; then
   echo "CONFIG_GLUSTERFS=y" >> $config_host_mak
 fi
 
+if test "$virtio_blk_data_plane" = "yes" ; then
+  echo "CONFIG_VIRTIO_BLK_DATA_PLANE=y" >> $config_host_mak
+fi
+
 # USB host support
 case "$usb" in
 linux)