4 In general features are intended to be supported indefinitely once
5 introduced into QEMU. In the event that a feature needs to be removed,
6 it will be listed in this section. The feature will remain functional for the
7 release in which it was deprecated and one further release. After these two
8 releases, the feature is liable to be removed. Deprecated features may also
9 generate warnings on the console when QEMU starts up, or if activated via a
10 monitor command, however, this is not a mandatory requirement.
12 Prior to the 2.10.0 release there was no official policy on how
13 long features would be deprecated prior to their removal, nor
14 any documented list of which features were deprecated. Thus
15 any features deprecated prior to 2.10.0 will be treated as if
16 they were first deprecated in the 2.10.0 release.
18 What follows is a list of all features currently marked as
21 System emulator command line arguments
22 --------------------------------------
24 ``-usbdevice`` (since 2.10.0)
25 '''''''''''''''''''''''''''''
27 The ``-usbdevice DEV`` argument is now a synonym for setting
28 the ``-device usb-DEV`` argument instead. The deprecated syntax
29 would automatically enable USB support on the machine type.
30 If using the new syntax, USB support must be explicitly
31 enabled via the ``-machine usb=on`` argument.
33 ``-drive file=json:{...{'driver':'file'}}`` (since 3.0)
34 '''''''''''''''''''''''''''''''''''''''''''''''''''''''
36 The 'file' driver for drives is no longer appropriate for character or host
37 devices and will only accept regular files (S_IFREG). The correct driver
38 for these file types is 'host_cdrom' or 'host_device' as appropriate.
40 ``-vnc acl`` (since 4.0.0)
41 ''''''''''''''''''''''''''
43 The ``acl`` option to the ``-vnc`` argument has been replaced
44 by the ``tls-authz`` and ``sasl-authz`` options.
46 ``QEMU_AUDIO_`` environment variables and ``-audio-help`` (since 4.0)
47 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
49 The ``-audiodev`` argument is now the preferred way to specify audio
50 backend settings instead of environment variables. To ease migration to
51 the new format, the ``-audiodev-help`` option can be used to convert
52 the current values of the environment variables to ``-audiodev`` options.
54 Creating sound card devices and vnc without ``audiodev=`` property (since 4.2)
55 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
57 When not using the deprecated legacy audio config, each sound card
58 should specify an ``audiodev=`` property. Additionally, when using
59 vnc, you should specify an ``audiodev=`` property if you plan to
60 transmit audio through the VNC protocol.
62 Creating sound card devices using ``-soundhw`` (since 5.1)
63 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
65 Sound card devices should be created using ``-device`` instead. The
66 names are the same for most devices. The exceptions are ``hda`` which
67 needs two devices (``-device intel-hda -device hda-duplex``) and
68 ``pcspk`` which can be activated using ``-machine
69 pcspk-audiodev=<name>``.
71 ``-mon ...,control=readline,pretty=on|off`` (since 4.1)
72 '''''''''''''''''''''''''''''''''''''''''''''''''''''''
74 The ``pretty=on|off`` switch has no effect for HMP monitors, but is
75 silently ignored. Using the switch with HMP monitors will become an
78 RISC-V ``-bios`` (since 5.1)
79 ''''''''''''''''''''''''''''
81 QEMU 4.1 introduced support for the -bios option in QEMU for RISC-V for the
82 RISC-V virt machine and sifive_u machine. QEMU 4.1 had no changes to the
83 default behaviour to avoid breakages.
85 QEMU 5.1 changes the default behaviour from ``-bios none`` to ``-bios default``.
87 QEMU 5.1 has three options:
88 1. ``-bios default`` - This is the current default behavior if no -bios option
89 is included. This option will load the default OpenSBI firmware automatically.
90 The firmware is included with the QEMU release and no user interaction is
91 required. All a user needs to do is specify the kernel they want to boot
92 with the -kernel option
93 2. ``-bios none`` - QEMU will not automatically load any firmware. It is up
94 to the user to load all the images they need.
95 3. ``-bios <file>`` - Tells QEMU to load the specified file as the firmwrae.
97 ``Configuring floppies with ``-global``
98 '''''''''''''''''''''''''''''''''''''''
100 Use ``-device floppy,...`` instead:
103 -global isa-fdc.driveA=...
104 -global sysbus-fdc.driveA=...
105 -global SUNW,fdtwo.drive=...
110 -device floppy,unit=0,drive=...
115 -global isa-fdc.driveB=...
116 -global sysbus-fdc.driveB=...
121 -device floppy,unit=1,drive=...
123 ``-drive`` with bogus interface type
124 ''''''''''''''''''''''''''''''''''''
126 Drives with interface types other than ``if=none`` are for onboard
127 devices. It is possible to use drives the board doesn't pick up with
128 -device. This usage is now deprecated. Use ``if=none`` instead.
130 Short-form boolean options (since 6.0)
131 ''''''''''''''''''''''''''''''''''''''
133 Boolean options such as ``share=on``/``share=off`` could be written
134 in short form as ``share`` and ``noshare``. This is now deprecated
135 and will cause a warning.
137 QEMU Machine Protocol (QMP) commands
138 ------------------------------------
140 ``blockdev-open-tray``, ``blockdev-close-tray`` argument ``device`` (since 2.8.0)
141 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
143 Use argument ``id`` instead.
145 ``eject`` argument ``device`` (since 2.8.0)
146 '''''''''''''''''''''''''''''''''''''''''''
148 Use argument ``id`` instead.
150 ``blockdev-change-medium`` argument ``device`` (since 2.8.0)
151 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
153 Use argument ``id`` instead.
155 ``block_set_io_throttle`` argument ``device`` (since 2.8.0)
156 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
158 Use argument ``id`` instead.
160 ``migrate_set_downtime`` and ``migrate_set_speed`` (since 2.8.0)
161 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
163 Use ``migrate-set-parameters`` instead.
165 ``query-named-block-nodes`` result ``encryption_key_missing`` (since 2.10.0)
166 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
170 ``query-block`` result ``inserted.encryption_key_missing`` (since 2.10.0)
171 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
175 ``blockdev-add`` empty string argument ``backing`` (since 2.10.0)
176 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
178 Use argument value ``null`` instead.
180 ``migrate-set-cache-size`` and ``query-migrate-cache-size`` (since 2.11.0)
181 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
183 Use ``migrate-set-parameters`` and ``query-migrate-parameters`` instead.
185 ``block-commit`` arguments ``base`` and ``top`` (since 3.1.0)
186 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
188 Use arguments ``base-node`` and ``top-node`` instead.
190 ``object-add`` option ``props`` (since 5.0)
191 '''''''''''''''''''''''''''''''''''''''''''
193 Specify the properties for the object as top-level arguments instead.
195 ``query-named-block-nodes`` and ``query-block`` result dirty-bitmaps[i].status (since 4.0)
196 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
198 The ``status`` field of the ``BlockDirtyInfo`` structure, returned by
199 these commands is deprecated. Two new boolean fields, ``recording`` and
200 ``busy`` effectively replace it.
202 ``query-block`` result field ``dirty-bitmaps`` (Since 4.2)
203 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
205 The ``dirty-bitmaps`` field of the ``BlockInfo`` structure, returned by
206 the query-block command is itself now deprecated. The ``dirty-bitmaps``
207 field of the ``BlockDeviceInfo`` struct should be used instead, which is the
208 type of the ``inserted`` field in query-block replies, as well as the
209 type of array items in query-named-block-nodes.
211 Since the ``dirty-bitmaps`` field is optionally present in both the old and
212 new locations, clients must use introspection to learn where to anticipate
213 the field if/when it does appear in command output.
215 ``query-cpus`` (since 2.12.0)
216 '''''''''''''''''''''''''''''
218 The ``query-cpus`` command is replaced by the ``query-cpus-fast`` command.
220 ``query-cpus-fast`` ``arch`` output member (since 3.0.0)
221 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''
223 The ``arch`` output member of the ``query-cpus-fast`` command is
224 replaced by the ``target`` output member.
226 ``query-events`` (since 4.0)
227 ''''''''''''''''''''''''''''
229 The ``query-events`` command has been superseded by the more powerful
230 and accurate ``query-qmp-schema`` command.
232 chardev client socket with ``wait`` option (since 4.0)
233 ''''''''''''''''''''''''''''''''''''''''''''''''''''''
235 Character devices creating sockets in client mode should not specify
236 the 'wait' field, which is only applicable to sockets in server mode
238 ``nbd-server-add`` and ``nbd-server-remove`` (since 5.2)
239 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''
241 Use the more generic commands ``block-export-add`` and ``block-export-del``
242 instead. As part of this deprecation, where ``nbd-server-add`` used a
243 single ``bitmap``, the new ``block-export-add`` uses a list of ``bitmaps``.
245 Human Monitor Protocol (HMP) commands
246 -------------------------------------
248 ``acl_show``, ``acl_reset``, ``acl_policy``, ``acl_add``, ``acl_remove`` (since 4.0.0)
249 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
251 The ``acl_show``, ``acl_reset``, ``acl_policy``, ``acl_add``, and
252 ``acl_remove`` commands are deprecated with no replacement. Authorization
253 for VNC should be performed using the pluggable QAuthZ objects.
258 ``moxie`` CPU (since 5.2.0)
259 '''''''''''''''''''''''''''
261 The ``moxie`` guest CPU support is deprecated and will be removed in
262 a future version of QEMU. It's unclear whether anybody is still using
263 CPU emulation in QEMU, and there are no test images available to make
264 sure that the code is still working.
266 ``lm32`` CPUs (since 5.2.0)
267 '''''''''''''''''''''''''''
269 The ``lm32`` guest CPU support is deprecated and will be removed in
270 a future version of QEMU. The only public user of this architecture
271 was the milkymist project, which has been dead for years; there was
272 never an upstream Linux port.
274 ``unicore32`` CPUs (since 5.2.0)
275 ''''''''''''''''''''''''''''''''
277 The ``unicore32`` guest CPU support is deprecated and will be removed in
278 a future version of QEMU. Support for this CPU was removed from the
279 upstream Linux kernel, and there is no available upstream toolchain
280 to build binaries for it.
282 ``Icelake-Client`` CPU Model (since 5.2.0)
283 ''''''''''''''''''''''''''''''''''''''''''
285 ``Icelake-Client`` CPU Models are deprecated. Use ``Icelake-Server`` CPU
288 MIPS ``I7200`` CPU Model (since 5.2)
289 ''''''''''''''''''''''''''''''''''''
291 The ``I7200`` guest CPU relies on the nanoMIPS ISA, which is deprecated
292 (the ISA has never been upstreamed to a compiler toolchain). Therefore
293 this CPU is also deprecated.
295 System emulator devices
296 -----------------------
298 ``ide-drive`` (since 4.2)
299 '''''''''''''''''''''''''
301 The 'ide-drive' device is deprecated. Users should use 'ide-hd' or
302 'ide-cd' as appropriate to get an IDE hard disk or CD-ROM as needed.
304 ``scsi-disk`` (since 4.2)
305 '''''''''''''''''''''''''
307 The 'scsi-disk' device is deprecated. Users should use 'scsi-hd' or
308 'scsi-cd' as appropriate to get a SCSI hard disk or CD-ROM as needed.
310 System emulator machines
311 ------------------------
313 ``pc-1.0``, ``pc-1.1``, ``pc-1.2`` and ``pc-1.3`` (since 5.0)
314 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
316 These machine types are very old and likely can not be used for live migration
317 from old QEMU versions anymore. A newer machine type should be used instead.
319 Raspberry Pi ``raspi2`` and ``raspi3`` machines (since 5.2)
320 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
322 The Raspberry Pi machines come in various models (A, A+, B, B+). To be able
323 to distinguish which model QEMU is implementing, the ``raspi2`` and ``raspi3``
324 machines have been renamed ``raspi2b`` and ``raspi3b``.
329 Emulated device options
330 '''''''''''''''''''''''
332 ``-device virtio-blk,scsi=on|off`` (since 5.0.0)
333 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
335 The virtio-blk SCSI passthrough feature is a legacy VIRTIO feature. VIRTIO 1.0
336 and later do not support it because the virtio-scsi device was introduced for
337 full SCSI support. Use virtio-scsi instead when SCSI passthrough is required.
339 Note this also applies to ``-device virtio-blk-pci,scsi=on|off``, which is an
345 ``"backing": ""`` (since 2.12.0)
346 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
348 In order to prevent QEMU from automatically opening an image's backing
349 chain, use ``"backing": null`` instead.
351 ``rbd`` keyvalue pair encoded filenames: ``""`` (since 3.1.0)
352 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
354 Options for ``rbd`` should be specified according to its runtime options,
355 like other block drivers. Legacy parsing of keyvalue pair encoded
356 filenames is useful to open images with the old format for backing files;
357 These image files should be updated to use the current format.
359 Example of legacy encoding::
361 json:{"file.driver":"rbd", "file.filename":"rbd:rbd/name"}
363 The above, converted to the current supported format::
365 json:{"file.driver":"rbd", "file.pool":"rbd", "file.image":"name"}
367 ``sheepdog`` driver (since 5.2.0)
368 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
370 The ``sheepdog`` block device driver is deprecated. The corresponding upstream
371 server project is no longer actively maintained. Users are recommended to switch
372 to an alternative distributed block device driver such as RBD. The
373 ``qemu-img convert`` command can be used to liberate existing data by moving
374 it out of sheepdog volumes into an alternative storage backend.
379 ``tilegx`` CPUs (since 5.1.0)
380 '''''''''''''''''''''''''''''
382 The ``tilegx`` guest CPU support (which was only implemented in
383 linux-user mode) is deprecated and will be removed in a future version
384 of QEMU. Support for this CPU was removed from the upstream Linux
385 kernel in 2018, and has also been dropped from glibc.
387 ``ppc64abi32`` CPUs (since 5.2.0)
388 '''''''''''''''''''''''''''''''''
390 The ``ppc64abi32`` architecture has a number of issues which regularly
391 trip up our CI testing and is suspected to be quite broken. For that
392 reason the maintainers strongly suspect no one actually uses it.
394 MIPS ``I7200`` CPU (since 5.2)
395 ''''''''''''''''''''''''''''''
397 The ``I7200`` guest CPU relies on the nanoMIPS ISA, which is deprecated
398 (the ISA has never been upstreamed to a compiler toolchain). Therefore
399 this CPU is also deprecated.
404 qemu-img amend to adjust backing file (since 5.1)
405 '''''''''''''''''''''''''''''''''''''''''''''''''
407 The use of ``qemu-img amend`` to modify the name or format of a qcow2
408 backing image is deprecated; this functionality was never fully
409 documented or tested, and interferes with other amend operations that
410 need access to the original backing image (such as deciding whether a
411 v3 zero cluster may be left unallocated when converting to a v2
412 image). Rather, any changes to the backing chain should be performed
413 with ``qemu-img rebase -u`` either before or after the remaining
414 changes being performed by amend, as appropriate.
416 qemu-img backing file without format (since 5.1)
417 ''''''''''''''''''''''''''''''''''''''''''''''''
419 The use of ``qemu-img create``, ``qemu-img rebase``, or ``qemu-img
420 convert`` to create or modify an image that depends on a backing file
421 now recommends that an explicit backing format be provided. This is
422 for safety: if QEMU probes a different format than what you thought,
423 the data presented to the guest will be corrupt; similarly, presenting
424 a raw image to a guest allows a potential security exploit if a future
425 probe sees a non-raw image based on guest writes.
427 To avoid the warning message, or even future refusal to create an
428 unsafe image, you must pass ``-o backing_fmt=`` (or the shorthand
429 ``-F`` during create) to specify the intended backing format. You may
430 use ``qemu-img rebase -u`` to retroactively add a backing format to an
431 existing image. However, be aware that there are already potential
432 security risks to blindly using ``qemu-img info`` to probe the format
433 of an untrusted backing image, when deciding what format to add into
436 Backwards compatibility
437 -----------------------
439 Runnability guarantee of CPU models (since 4.1.0)
440 '''''''''''''''''''''''''''''''''''''''''''''''''
442 Previous versions of QEMU never changed existing CPU models in
443 ways that introduced additional host software or hardware
444 requirements to the VM. This allowed management software to
445 safely change the machine type of an existing VM without
446 introducing new requirements ("runnability guarantee"). This
447 prevented CPU models from being updated to include CPU
448 vulnerability mitigations, leaving guests vulnerable in the
449 default configuration.
451 The CPU model runnability guarantee won't apply anymore to
452 existing CPU models. Management software that needs runnability
453 guarantees must resolve the CPU model aliases using the
454 ``alias-of`` field returned by the ``query-cpu-definitions`` QMP
457 While those guarantees are kept, the return value of
458 ``query-cpu-definitions`` will have existing CPU model aliases
459 point to a version that doesn't break runnability guarantees
460 (specifically, version 1 of those CPU models). In future QEMU
461 versions, aliases will point to newer CPU model versions
462 depending on the machine type, so management software must
463 resolve CPU model aliases before starting a virtual machine.
471 The ``nanoMIPS`` ISA has never been upstreamed to any compiler toolchain.
472 As it is hard to generate binaries for it, declare it deprecated.