feat(sys-kernel/coreos-kernel): Add 9P virtio fs support.

This allows qemu virtual machines to access plain directories on the
host system in addition to the usual disk/filesystem images.

sdk_container/src/third_party/coreos-overlay/eclass/cros-kernel/x86_64_defconfig

@@ -1,6 +1,6 @@
 #
 # Automatically generated file; DO NOT EDIT.
-# Linux/x86 3.10.5 Kernel Configuration
+# Linux/x86 3.10.1 Kernel Configuration
 #
 CONFIG_64BIT=y
 CONFIG_X86_64=y
@@ -1008,7 +1008,9 @@ CONFIG_FIB_RULES=y
 # CONFIG_WIRELESS is not set
 # CONFIG_WIMAX is not set
 # CONFIG_RFKILL is not set
-# CONFIG_NET_9P is not set
+CONFIG_NET_9P=m
+CONFIG_NET_9P_VIRTIO=m
+# CONFIG_NET_9P_DEBUG is not set
 # CONFIG_CAIF is not set
 # CONFIG_CEPH_LIB is not set
 # CONFIG_NFC is not set
@@ -2538,6 +2540,8 @@ CONFIG_SUNRPC_DEBUG=y
 # CONFIG_NCP_FS is not set
 # CONFIG_CODA_FS is not set
 # CONFIG_AFS_FS is not set
+CONFIG_9P_FS=m
+CONFIG_9P_FS_POSIX_ACL=y
 CONFIG_NLS=y
 CONFIG_NLS_DEFAULT="utf8"
 CONFIG_NLS_CODEPAGE_437=y

sdk_container/src/third_party/coreos-overlay/profiles/default/linux/package.use

@@ -36,7 +36,7 @@ net-misc/dhcpcd -crash
 # this comment was here:
 # build kvm with X and sdl so we have an option of running it with local
 # display without VNC
-app-emulation/qemu	aio caps curl jpeg ncurses png python seccomp threads uuid vhost-net vnc qemu_softmmu_targets_x86_64
+app-emulation/qemu	aio caps curl jpeg ncurses png python seccomp threads uuid vhost-net virtfs vnc xattr qemu_softmmu_targets_x86_64
 dev-libs/libaio		static-libs
 cross-armv7a-cros-linux-gnueabi/gcc   hardfp
 cross-armv6j-cros-linux-gnueabi/gcc   hardfp -thumb