1 # SPDX-License-Identifier: GPL-2.0
3 menu "UML Character Devices"
9 console driver which dumps all printk messages to stderr.
12 bool "Virtual serial line"
14 The User-Mode Linux environment allows you to create virtual serial
15 lines on the UML that are usually made to show up on the host as
18 See <http://user-mode-linux.sourceforge.net/old/input.html> for more
19 information and command line examples of how to use this facility.
21 Unless you have a specific reason for disabling this, say Y.
24 bool "null channel support"
26 This option enables support for attaching UML consoles and serial
27 lines to a device similar to /dev/null. Data written to it disappears
28 and there is never any data to be read.
31 bool "port channel support"
33 This option enables support for attaching UML consoles and serial
34 lines to host portals. They may be accessed with 'telnet <host>
35 <port number>'. Any number of consoles and serial lines may be
36 attached to a single portal, although what UML device you get when
37 you telnet to that portal will be unpredictable.
38 It is safe to say 'Y' here.
41 bool "pty channel support"
43 This option enables support for attaching UML consoles and serial
44 lines to host pseudo-terminals. Access to both traditional
45 pseudo-terminals (/dev/pty*) and pts pseudo-terminals are controlled
46 with this option. The assignment of UML devices to host devices
47 will be announced in the kernel message log.
48 It is safe to say 'Y' here.
51 bool "tty channel support"
53 This option enables support for attaching UML consoles and serial
54 lines to host terminals. Access to both virtual consoles
55 (/dev/tty*) and the slave side of pseudo-terminals (/dev/ttyp* and
56 /dev/pts/*) are controlled by this option.
57 It is safe to say 'Y' here.
60 bool "xterm channel support"
62 This option enables support for attaching UML consoles and serial
63 lines to xterms. Each UML device so assigned will be brought up in
65 It is safe to say 'Y' here.
69 default !(XTERM_CHAN && TTY_CHAN && PTY_CHAN && PORT_CHAN && NULL_CHAN)
72 string "Default main console channel initialization"
75 This is the string describing the channel to which the main console
76 will be attached by default. This value can be overridden from the
77 command line. The default value is "fd:0,fd:1", which attaches the
78 main console to stdin and stdout.
79 It is safe to leave this unchanged.
82 string "Default console channel initialization"
85 This is the string describing the channel to which all consoles
86 except the main console will be attached by default. This value can
87 be overridden from the command line. The default value is "xterm",
88 which brings them up in xterms.
89 It is safe to leave this unchanged, although you may wish to change
90 this if you expect the UML that you build to be run in environments
91 which don't have X or xterm available.
94 string "Default serial line channel initialization"
97 This is the string describing the channel to which the serial lines
98 will be attached by default. This value can be overridden from the
99 command line. The default value is "pty", which attaches them to
100 traditional pseudo-terminals.
101 It is safe to leave this unchanged, although you may wish to change
102 this if you expect the UML that you build to be run in environments
103 which don't have a set of /dev/pty* devices.
106 tristate "Sound support"
108 select SOUND_OSS_CORE
110 This option enables UML sound support. If enabled, it will pull in
111 the UML hostaudio relay, which acts as a intermediary
112 between the host's dsp and mixer devices and the UML sound system.
113 It is safe to say 'Y' here.
117 menu "UML Network Devices"
122 bool "Virtual network device"
124 While the User-Mode port cannot directly talk to any physical
125 hardware devices, this choice and the following transport options
126 provide one or more virtual network devices through which the UML
127 kernels can talk to each other, the host, and with the host's help,
128 machines on the outside world.
130 For more information, including explanations of the networking and
131 sample configurations, see
132 <http://user-mode-linux.sourceforge.net/old/networking.html>.
134 If you'd like to be able to enable networking in the User-Mode
135 linux environment, say Y; otherwise say N. Note that you must
136 enable at least one of the following transport options to actually
137 make use of UML networking.
139 config UML_NET_ETHERTAP
140 bool "Ethertap transport"
143 The Ethertap User-Mode Linux network transport allows a single
144 running UML to exchange packets with its host over one of the
145 host's Ethertap devices, such as /dev/tap0. Additional running
146 UMLs can use additional Ethertap devices, one per running UML.
147 While the UML believes it's on a (multi-device, broadcast) virtual
148 Ethernet network, it's in fact communicating over a point-to-point
151 To use this, your host kernel must have support for Ethertap
152 devices. Also, if your host kernel is 2.4.x, it must have
153 CONFIG_NETLINK_DEV configured as Y or M.
155 For more information, see
156 <http://user-mode-linux.sourceforge.net/old/networking.html> That site
157 has examples of the UML command line to use to enable Ethertap
160 If you'd like to set up an IP network with the host and/or the
161 outside world, say Y to this, the Daemon Transport and/or the
162 Slip Transport. You'll need at least one of them, but may choose
163 more than one without conflict. If you don't need UML networking,
166 config UML_NET_TUNTAP
167 bool "TUN/TAP transport"
170 The UML TUN/TAP network transport allows a UML instance to exchange
171 packets with the host over a TUN/TAP device. This option will only
172 work with a 2.4 host, unless you've applied the TUN/TAP patch to
173 your 2.2 host kernel.
175 To use this transport, your host kernel must have support for TUN/TAP
176 devices, either built-in or as a module.
179 bool "SLIP transport"
182 The slip User-Mode Linux network transport allows a running UML to
183 network with its host over a point-to-point link. Unlike Ethertap,
184 which can carry any Ethernet frame (and hence even non-IP packets),
185 the slip transport can only carry IP packets.
187 To use this, your host must support slip devices.
189 For more information, see
190 <http://user-mode-linux.sourceforge.net/old/networking.html>.
191 has examples of the UML command line to use to enable slip
192 networking, and details of a few quirks with it.
194 The Ethertap Transport is preferred over slip because of its
195 limitations. If you prefer slip, however, say Y here. Otherwise
196 choose the Multicast transport (to network multiple UMLs on
197 multiple hosts), Ethertap (to network with the host and the
198 outside world), and/or the Daemon transport (to network multiple
199 UMLs on a single host). You may choose more than one without
200 conflict. If you don't need UML networking, say N.
202 config UML_NET_DAEMON
203 bool "Daemon transport"
206 This User-Mode Linux network transport allows one or more running
207 UMLs on a single host to communicate with each other, but not to
210 To use this form of networking, you'll need to run the UML
211 networking daemon on the host.
213 For more information, see
214 <http://user-mode-linux.sourceforge.net/old/networking.html> That site
215 has examples of the UML command line to use to enable Daemon
218 If you'd like to set up a network with other UMLs on a single host,
219 say Y. If you need a network between UMLs on multiple physical
220 hosts, choose the Multicast Transport. To set up a network with
221 the host and/or other IP machines, say Y to the Ethertap or Slip
222 transports. You'll need at least one of them, but may choose
223 more than one without conflict. If you don't need UML networking,
226 config UML_NET_VECTOR
227 bool "Vector I/O high performance network devices"
230 This User-Mode Linux network driver uses multi-message send
231 and receive functions. The host running the UML guest must have
232 a linux kernel version above 3.0 and a libc version > 2.13.
233 This driver provides tap, raw, gre and l2tpv3 network transports
234 with up to 4 times higher network throughput than the UML network
241 This User-Mode Linux network transport allows one or more running
242 UMLs on a single host to communicate with each other and also
243 with the rest of the world using Virtual Distributed Ethernet,
244 an improved fork of uml_switch.
246 You must have libvdeplug installed in order to build the vde
249 To use this form of networking, you will need to run vde_switch
252 For more information, see <http://wiki.virtualsquare.org/>
253 That site has a good overview of what VDE is and also examples
254 of the UML command line to use to enable VDE networking.
256 If you need UML networking with VDE,
260 bool "Multicast transport"
263 This Multicast User-Mode Linux network transport allows multiple
264 UMLs (even ones running on different host machines!) to talk to
265 each other over a virtual ethernet network. However, it requires
266 at least one UML with one of the other transports to act as a
267 bridge if any of them need to be able to talk to their hosts or any
270 To use this, your host kernel(s) must support IP Multicasting.
272 For more information, see
273 <http://user-mode-linux.sourceforge.net/old/networking.html> That site
274 has examples of the UML command line to use to enable Multicast
275 networking, and notes about the security of this approach.
277 If you need UMLs on multiple physical hosts to communicate as if
278 they shared an Ethernet network, say Y. If you need to communicate
279 with other IP machines, make sure you select one of the other
280 transports (possibly in addition to Multicast; they're not
281 exclusive). If you don't need to network UMLs say N to each of
285 bool "pcap transport"
288 The pcap transport makes a pcap packet stream on the host look
289 like an ethernet device inside UML. This is useful for making
290 UML act as a network monitor for the host. You must have libcap
291 installed in order to build the pcap transport into UML.
293 For more information, see
294 <http://user-mode-linux.sourceforge.net/old/networking.html> That site
295 has examples of the UML command line to use to enable this option.
297 If you intend to use UML as a network monitor for the host, say
298 Y here. Otherwise, say N.
301 bool "SLiRP transport"
304 The SLiRP User-Mode Linux network transport allows a running UML
305 to network by invoking a program that can handle SLIP encapsulated
306 packets. This is commonly (but not limited to) the application
307 known as SLiRP, a program that can re-socket IP packets back onto
308 he host on which it is run. Only IP packets are supported,
309 unlike other network transports that can handle all Ethernet
310 frames. In general, slirp allows the UML the same IP connectivity
311 to the outside world that the host user is permitted, and unlike
312 other transports, SLiRP works without the need of root level
313 privleges, setuid binaries, or SLIP devices on the host. This
314 also means not every type of connection is possible, but most
315 situations can be accommodated with carefully crafted slirp
316 commands that can be passed along as part of the network device's
317 setup string. The effect of this transport on the UML is similar
318 that of a host behind a firewall that masquerades all network
319 connections passing through it (but is less secure).
321 To use this you should first have slirp compiled somewhere
322 accessible on the host, and have read its documentation. If you
323 don't need UML networking, say N.
325 Startup example: "eth0=slirp,FE:FD:01:02:03:04,/usr/local/bin/slirp"
330 bool "UML driver for virtio devices"
333 This driver provides support for virtio based paravirtual device
334 drivers over vhost-user sockets.