diff --git a/libguestfs.changes b/libguestfs.changes
index 0442249..5a2ea63 100644
--- a/libguestfs.changes
+++ b/libguestfs.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Thu Sep 13 14:53:39 CEST 2012 - ohering@suse.de
+
+- force virtio-blk usage only if the guest kernel has no virtio-scsi
+
 -------------------------------------------------------------------
 Thu Sep 13 10:39:54 CEST 2012 - ohering@suse.de
 
diff --git a/libguestfs.spec b/libguestfs.spec
index bcb266f..86707e7 100644
--- a/libguestfs.spec
+++ b/libguestfs.spec
@@ -339,8 +339,18 @@ virtual machines.
 export vmchannel_test=no
 export QEMU=/usr/bin/qemu-kvm
 # for configure macro below
-CFLAGS="$RPM_OPT_FLAGS -Wno-unused -DGUESTFS_QEMU_NO_VIRTIO_BLK"
-CXXFLAGS="$RPM_OPT_FLAGS -Wno-unused -DGUESTFS_QEMU_NO_VIRTIO_BLK"
+CFLAGS="$RPM_OPT_FLAGS -Wno-unused"
+CXXFLAGS="$RPM_OPT_FLAGS -Wno-unused"
+# If the kernel happens to have no virtio-scsi force virtio-blk usage in the tools
+# This is true for kernel.rpm included in 12.1 and older
+if /sbin/modinfo -k `/sbin/get_kernel_version /boot/vmlinuz` virtio-scsi
+then
+	: use virtio-scsi, which is the default in libguestfs
+else
+	CFLAGS="$CFLAGS -DGUESTFS_QEMU_NO_VIRTIO_BLK"
+	CXXFLAGS="$CXXFLAGS -DGUESTFS_QEMU_NO_VIRTIO_BLK"
+fi
+#
 autoreconf -fi
 %configure \
 	--help || :