Global USE flags

Flag Description Packages
doc 2
selinux 3

Local USE flags

app-emulation

qemu

Flag Description
$(printf
accessibility Adds support for braille displays using brltty
aio Enables support for Linux's Async IO
alsa Enable alsa output for sound emulation
bpf Enable eBPF support for RSS implementation.
bzip2
capstone Enable disassembly support with <pkg>dev-libs/capstone</pkg>
curl Support ISOs / -cdrom directives via HTTP or HTTPS.
debug
fdt Enables firmware device tree support
fuse Enables FUSE block device export
glusterfs Enables GlusterFS cluster fileystem via <pkg>sys-cluster/glusterfs</pkg>
gnutls Enable TLS support for the VNC console server. For 1.4 and newer this also enables WebSocket support. For 2.0 through 2.3 also enables disk quorum support.
gtk
infiniband
io-uring Enable efficient I/O via <pkg>sys-libs/liburing</pkg>.
iscsi Enable direct iSCSI support via <pkg>net-libs/libiscsi</pkg> instead of indirectly via the Linux block layer that <pkg>sys-block/open-iscsi</pkg> does.
jack
jemalloc Enable jemalloc allocator support
jpeg Enable jpeg image support for the VNC console server
keyutils
lzo
multipath Enable multipath persistent reservation passthrough via <pkg>sys-fs/multipath-tools</pkg>.
ncurses Enable the ncurses-based console
nfs Enable NFS support
nls
numa Enable NUMA support
opengl
oss
pam
pin-upstream-blobs Pin the versions of BIOS firmware to the version included in the upstream release. This is needed to sanely support migration/suspend/resume/snapshotting/etc... of instances. When the blobs are different, random corruption/bugs/crashes/etc... may be observed.
pipewire Enable pipewire output for sound emulation
plugins Enable qemu plugin API via shared library loading.
png Enable png image support for the VNC console server
pulseaudio Enable pulseaudio output for sound emulation
python
rbd Enable rados block device backend support, see https://docs.ceph.com/en/mimic/rbd/qemu-rbd/
sasl
sdl Enable the SDL-based console
sdl-image SDL Image support for icons
seccomp
slirp Enable TCP/IP in hypervisor via <pkg>net-libs/libslirp</pkg>
smartcard
snappy
spice Enable Spice protocol support via <pkg>app-emulation/spice</pkg>
ssh Enable SSH based block device support via <pkg>net-libs/libssh2</pkg>
static Build the User and Software MMU (system) targets as well as tools as static binaries
static-user Build the User targets as static binaries
systemtap Enable SystemTAP/DTrace tracing
test
udev
usb Enable USB passthrough via <pkg>dev-libs/libusb</pkg>
usbredir Use <pkg>sys-apps/usbredir</pkg> to redirect USB devices to another machine over TCP
vde Enable VDE-based networking
vhost-net Enable accelerated networking using vhost-net, see https://www.linux-kvm.org/page/VhostNet
virgl Enable experimental Virgil 3d (virtual software GPU)
virtfs Enable VirtFS via virtio-9p-pci / fsdev. See https://wiki.qemu.org/Documentation/9psetup
vnc
vte Enable terminal support (<pkg>x11-libs/vte</pkg>) in the GTK+ interface
xattr Add support for getting and setting POSIX extended attributes, through <pkg>sys-apps/attr</pkg>. Requisite for the virtfs backend.
xen Enables support for Xen backends
zstd

media-libs

virglrenderer

Flag Description
static-libs
vulkan

sys-apps

xdg-desktop-portal

Flag Description
geolocation
screencast Enable screencast portal using <pkg>media-video/pipewire</pkg>

x11-misc

xdg-utils

Flag Description
dbus
gnome