[tgamblin@megalith build]$ tree ../../meta-tgamblin-kernel/recipes-kernel/
../../meta-tgamblin-kernel/recipes-kernel/
└── linux
    ├── linux-yocto
    │   ├── defconfig
    │   └── virtio.cfg
    └── linux-yocto_6.%.bbappend

[tgamblin@megalith build]$ cat ../../meta-tgamblin-kernel/recipes-kernel/linux/linux-yocto_6.%.bbappend
FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:"
SRC_URI += "file://virtio.cfg"