diff --git a/meta/classes-recipe/qemuboot.bbclass b/meta/classes-recipe/qemuboot.bbclass
index 5a0e50ccfc..444871438d 100644
--- a/meta/classes-recipe/qemuboot.bbclass
+++ b/meta/classes-recipe/qemuboot.bbclass
@@ -86,6 +86,8 @@
 #                      without the need to specify a dedicated qemu configuration
 #
 # QB_GRAPHICS: QEMU video card type (e.g. "-vga std")
+# QB_NFSROOTFS_EXTRA_OPT: extra options to be appended to the nfs rootfs options in kernel boot arg, e.g.,
+#                         "wsize=4096,rsize=4096"
 #
 # Usage:
 # IMAGE_CLASSES += "qemuboot"
@@ -103,6 +105,7 @@ QB_CMDLINE_IP_SLIRP ?= "ip=dhcp"
 QB_CMDLINE_IP_TAP ?= "ip=192.168.7.@CLIENT@::192.168.7.@GATEWAY@:255.255.255.0::eth0:off:8.8.8.8"
 QB_ROOTFS_EXTRA_OPT ?= ""
 QB_GRAPHICS ?= ""
+QB_NFSROOTFS_EXTRA_OPT ?= ""
 
 # This should be kept align with ROOT_VM
 QB_DRIVE_TYPE ?= "/dev/sd"