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7f800d34 MAL |
1 | .. _Deprecated features: |
2 | ||
41fba161 PM |
3 | Deprecated features |
4 | =================== | |
5 | ||
6 | In general features are intended to be supported indefinitely once | |
7 | introduced into QEMU. In the event that a feature needs to be removed, | |
ef1f5b0a SH |
8 | it will be listed in this section. The feature will remain functional for the |
9 | release in which it was deprecated and one further release. After these two | |
10 | releases, the feature is liable to be removed. Deprecated features may also | |
11 | generate warnings on the console when QEMU starts up, or if activated via a | |
12 | monitor command, however, this is not a mandatory requirement. | |
41fba161 PM |
13 | |
14 | Prior to the 2.10.0 release there was no official policy on how | |
15 | long features would be deprecated prior to their removal, nor | |
16 | any documented list of which features were deprecated. Thus | |
17 | any features deprecated prior to 2.10.0 will be treated as if | |
18 | they were first deprecated in the 2.10.0 release. | |
19 | ||
20 | What follows is a list of all features currently marked as | |
21 | deprecated. | |
22 | ||
bb9ecae7 AB |
23 | Build options |
24 | ------------- | |
25 | ||
26 | ``gprof`` builds (since 8.0) | |
27 | '''''''''''''''''''''''''''' | |
28 | ||
29 | The ``--enable-gprof`` configure setting relies on compiler | |
30 | instrumentation to gather its data which can distort the generated | |
31 | profile. As other non-instrumenting tools are available that give a | |
32 | more holistic view of the system with non-instrumented binaries we are | |
33 | deprecating the build option and no longer defend it in CI. The | |
34 | ``--enable-gcov`` build option remains for analysis test case | |
35 | coverage. | |
36 | ||
41fba161 PM |
37 | System emulator command line arguments |
38 | -------------------------------------- | |
39 | ||
41fba161 PM |
40 | ``QEMU_AUDIO_`` environment variables and ``-audio-help`` (since 4.0) |
41 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
42 | ||
43 | The ``-audiodev`` argument is now the preferred way to specify audio | |
44 | backend settings instead of environment variables. To ease migration to | |
45 | the new format, the ``-audiodev-help`` option can be used to convert | |
46 | the current values of the environment variables to ``-audiodev`` options. | |
47 | ||
48 | Creating sound card devices and vnc without ``audiodev=`` property (since 4.2) | |
49 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
50 | ||
51 | When not using the deprecated legacy audio config, each sound card | |
52 | should specify an ``audiodev=`` property. Additionally, when using | |
76ca4b58 | 53 | vnc, you should specify an ``audiodev=`` property if you plan to |
41fba161 PM |
54 | transmit audio through the VNC protocol. |
55 | ||
ccd3b3b8 PB |
56 | Short-form boolean options (since 6.0) |
57 | '''''''''''''''''''''''''''''''''''''' | |
58 | ||
59 | Boolean options such as ``share=on``/``share=off`` could be written | |
60 | in short form as ``share`` and ``noshare``. This is now deprecated | |
61 | and will cause a warning. | |
a1b40bda | 62 | |
fe636424 PB |
63 | ``delay`` option for socket character devices (since 6.0) |
64 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
65 | ||
66 | The replacement for the ``nodelay`` short-form boolean option is ``nodelay=on`` | |
67 | rather than ``delay=off``. | |
68 | ||
c2511b16 YW |
69 | ``-smp`` ("parameter=0" SMP configurations) (since 6.2) |
70 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
71 | ||
72 | Specified CPU topology parameters must be greater than zero. | |
73 | ||
74 | In the SMP configuration, users should either provide a CPU topology | |
75 | parameter with a reasonable value (greater than zero) or just omit it | |
76 | and QEMU will compute the missing value. | |
77 | ||
78 | However, historically it was implicitly allowed for users to provide | |
79 | a parameter with zero value, which is meaningless and could also possibly | |
80 | cause unexpected results in the -smp parsing. So support for this kind of | |
81 | configurations (e.g. -smp 8,sockets=0) is deprecated since 6.2 and will | |
82 | be removed in the near future, users have to ensure that all the topology | |
83 | members described with -smp are greater than zero. | |
39c4c27d | 84 | |
67f14574 MM |
85 | Plugin argument passing through ``arg=<string>`` (since 6.1) |
86 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
87 | ||
88 | Passing TCG plugins arguments through ``arg=`` is redundant is makes the | |
89 | command-line less readable, especially when the argument itself consist of a | |
90 | name and a value, e.g. ``-plugin plugin_name,arg="arg_name=arg_value"``. | |
91 | Therefore, the usage of ``arg`` is redundant. Single-word arguments are treated | |
92 | as short-form boolean values, and passed to plugins as ``arg_name=on``. | |
93 | However, short-form booleans are deprecated and full explicit ``arg_name=on`` | |
94 | form is preferred. | |
95 | ||
df37330c TH |
96 | ``-no-hpet`` (since 8.0) |
97 | '''''''''''''''''''''''' | |
98 | ||
99 | The HPET setting has been turned into a machine property. | |
100 | Use ``-machine hpet=off`` instead. | |
101 | ||
fffa36b6 TH |
102 | ``-no-acpi`` (since 8.0) |
103 | '''''''''''''''''''''''' | |
104 | ||
105 | The ``-no-acpi`` setting has been turned into a machine property. | |
106 | Use ``-machine acpi=off`` instead. | |
107 | ||
90c167a1 TH |
108 | ``-accel hax`` (since 8.0) |
109 | '''''''''''''''''''''''''' | |
110 | ||
111 | The HAXM project has been retired (see https://github.com/intel/haxm#status). | |
112 | Use "whpx" (on Windows) or "hvf" (on macOS) instead. | |
113 | ||
80bd81ca CI |
114 | ``-async-teardown`` (since 8.1) |
115 | ''''''''''''''''''''''''''''''' | |
116 | ||
117 | Use ``-run-with async-teardown=on`` instead. | |
118 | ||
12fd0f41 PM |
119 | ``-singlestep`` (since 8.1) |
120 | ''''''''''''''''''''''''''' | |
121 | ||
122 | The ``-singlestep`` option has been turned into an accelerator property, | |
123 | and given a name that better reflects what it actually does. | |
124 | Use ``-accel tcg,one-insn-per-tb=on`` instead. | |
125 | ||
126 | User-mode emulator command line arguments | |
127 | ----------------------------------------- | |
128 | ||
129 | ``-singlestep`` (since 8.1) | |
130 | ''''''''''''''''''''''''''' | |
131 | ||
132 | The ``-singlestep`` option has been given a name that better reflects | |
133 | what it actually does. For both linux-user and bsd-user, use the | |
134 | new ``-one-insn-per-tb`` option instead. | |
67f14574 | 135 | |
41fba161 PM |
136 | QEMU Machine Protocol (QMP) commands |
137 | ------------------------------------ | |
138 | ||
e2cc363b YW |
139 | ``blockdev-open-tray``, ``blockdev-close-tray`` argument ``device`` (since 2.8) |
140 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
73756ae3 MA |
141 | |
142 | Use argument ``id`` instead. | |
143 | ||
e2cc363b YW |
144 | ``eject`` argument ``device`` (since 2.8) |
145 | ''''''''''''''''''''''''''''''''''''''''' | |
73756ae3 MA |
146 | |
147 | Use argument ``id`` instead. | |
148 | ||
e2cc363b YW |
149 | ``blockdev-change-medium`` argument ``device`` (since 2.8) |
150 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
73756ae3 MA |
151 | |
152 | Use argument ``id`` instead. | |
153 | ||
e2cc363b YW |
154 | ``block_set_io_throttle`` argument ``device`` (since 2.8) |
155 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
73756ae3 MA |
156 | |
157 | Use argument ``id`` instead. | |
158 | ||
e2cc363b YW |
159 | ``blockdev-add`` empty string argument ``backing`` (since 2.10) |
160 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
73756ae3 MA |
161 | |
162 | Use argument value ``null`` instead. | |
163 | ||
e2cc363b YW |
164 | ``block-commit`` arguments ``base`` and ``top`` (since 3.1) |
165 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
73756ae3 MA |
166 | |
167 | Use arguments ``base-node`` and ``top-node`` instead. | |
168 | ||
443127e8 KW |
169 | ``nbd-server-add`` and ``nbd-server-remove`` (since 5.2) |
170 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
171 | ||
172 | Use the more generic commands ``block-export-add`` and ``block-export-del`` | |
cbad81ce EB |
173 | instead. As part of this deprecation, where ``nbd-server-add`` used a |
174 | single ``bitmap``, the new ``block-export-add`` uses a list of ``bitmaps``. | |
443127e8 | 175 | |
75ecee72 MA |
176 | ``query-qmp-schema`` return value member ``values`` (since 6.2) |
177 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
178 | ||
179 | Member ``values`` in return value elements with meta-type ``enum`` is | |
180 | deprecated. Use ``members`` instead. | |
181 | ||
1084159b VSO |
182 | ``drive-backup`` (since 6.2) |
183 | '''''''''''''''''''''''''''' | |
184 | ||
185 | Use ``blockdev-backup`` in combination with ``blockdev-add`` instead. | |
186 | This change primarily separates the creation/opening process of the backup | |
187 | target with explicit, separate steps. ``blockdev-backup`` uses mostly the | |
188 | same arguments as ``drive-backup``, except the ``format`` and ``mode`` | |
189 | options are removed in favor of using explicit ``blockdev-create`` and | |
190 | ``blockdev-add`` calls. See :doc:`/interop/live-block-operations` for | |
191 | details. | |
192 | ||
4d8b0f0a KW |
193 | Incorrectly typed ``device_add`` arguments (since 6.2) |
194 | '''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
195 | ||
196 | Due to shortcomings in the internal implementation of ``device_add``, QEMU | |
197 | incorrectly accepts certain invalid arguments: Any object or list arguments are | |
198 | silently ignored. Other argument types are not checked, but an implicit | |
199 | conversion happens, so that e.g. string values can be assigned to integer | |
200 | device properties or vice versa. | |
201 | ||
202 | This is a bug in QEMU that will be fixed in the future so that previously | |
203 | accepted incorrect commands will return an error. Users should make sure that | |
204 | all arguments passed to ``device_add`` are consistent with the documented | |
205 | property types. | |
206 | ||
34c18203 PM |
207 | ``StatusInfo`` member ``singlestep`` (since 8.1) |
208 | '''''''''''''''''''''''''''''''''''''''''''''''' | |
209 | ||
210 | The ``singlestep`` member of the ``StatusInfo`` returned from the | |
211 | ``query-status`` command is deprecated. This member has a confusing | |
212 | name and it never did what the documentation claimed or what its name | |
213 | suggests. We do not believe that anybody is actually using the | |
214 | information provided in this member. | |
215 | ||
216 | The information it reports is whether the TCG JIT is in "one | |
217 | instruction per translated block" mode (which can be set on the | |
218 | command line or via the HMP, but not via QMP). The information remains | |
219 | available via the HMP 'info jit' command. | |
220 | ||
e9ccfdd9 PM |
221 | Human Monitor Protocol (HMP) commands |
222 | ------------------------------------- | |
223 | ||
224 | ``singlestep`` (since 8.1) | |
225 | '''''''''''''''''''''''''' | |
226 | ||
227 | The ``singlestep`` command has been replaced by the ``one-insn-per-tb`` | |
228 | command, which has the same behaviour but a less misleading name. | |
229 | ||
54ab3c3f AB |
230 | Host Architectures |
231 | ------------------ | |
232 | ||
233 | BE MIPS (since 7.2) | |
234 | ''''''''''''''''''' | |
235 | ||
236 | As Debian 10 ("Buster") moved into LTS the big endian 32 bit version of | |
237 | MIPS moved out of support making it hard to maintain our | |
238 | cross-compilation CI tests of the architecture. As we no longer have | |
239 | CI coverage support may bitrot away before the deprecation process | |
240 | completes. The little endian variants of MIPS (both 32 and 64 bit) are | |
241 | still a supported host architecture. | |
242 | ||
5c27baf9 TH |
243 | System emulation on 32-bit x86 hosts (since 8.0) |
244 | '''''''''''''''''''''''''''''''''''''''''''''''' | |
245 | ||
246 | Support for 32-bit x86 host deployments is increasingly uncommon in mainstream | |
247 | OS distributions given the widespread availability of 64-bit x86 hardware. | |
248 | The QEMU project no longer considers 32-bit x86 support for system emulation to | |
249 | be an effective use of its limited resources, and thus intends to discontinue | |
250 | it. Since all recent x86 hardware from the past >10 years is capable of the | |
251 | 64-bit x86 extensions, a corresponding 64-bit OS should be used instead. | |
252 | ||
253 | ||
d43f1670 DHB |
254 | QEMU API (QAPI) events |
255 | ---------------------- | |
256 | ||
257 | ``MEM_UNPLUG_ERROR`` (since 6.2) | |
258 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
259 | ||
260 | Use the more generic event ``DEVICE_UNPLUG_GUEST_ERROR`` instead. | |
261 | ||
262 | ||
41fba161 PM |
263 | System emulator machines |
264 | ------------------------ | |
265 | ||
ac64ebbe PM |
266 | Arm ``virt`` machine ``dtb-kaslr-seed`` property (since 7.1) |
267 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
5242876f JD |
268 | |
269 | The ``dtb-kaslr-seed`` property on the ``virt`` board has been | |
270 | deprecated; use the new name ``dtb-randomness`` instead. The new name | |
271 | better reflects the way this property affects all random data within | |
272 | the device tree blob, not just the ``kaslr-seed`` node. | |
273 | ||
f59fb188 TH |
274 | ``pc-i440fx-1.4`` up to ``pc-i440fx-1.7`` (since 7.0) |
275 | ''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
276 | ||
277 | These old machine types are quite neglected nowadays and thus might have | |
278 | various pitfalls with regards to live migration. Use a newer machine type | |
279 | instead. | |
280 | ||
281 | ||
cdcf766d IM |
282 | Backend options |
283 | --------------- | |
284 | ||
285 | Using non-persistent backing file with pmem=on (since 6.1) | |
286 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
287 | ||
288 | This option is used when ``memory-backend-file`` is consumed by emulated NVDIMM | |
289 | device. However enabling ``memory-backend-file.pmem`` option, when backing file | |
290 | is (a) not DAX capable or (b) not on a filesystem that support direct mapping | |
291 | of persistent memory, is not safe and may lead to data loss or corruption in case | |
292 | of host crash. | |
293 | Options are: | |
294 | ||
295 | - modify VM configuration to set ``pmem=off`` to continue using fake NVDIMM | |
296 | (without persistence guaranties) with backing file on non DAX storage | |
297 | - move backing file to NVDIMM storage and keep ``pmem=on`` | |
298 | (to have NVDIMM with persistence guaranties). | |
299 | ||
41fba161 PM |
300 | Device options |
301 | -------------- | |
302 | ||
303 | Emulated device options | |
304 | ''''''''''''''''''''''' | |
305 | ||
e2cc363b YW |
306 | ``-device virtio-blk,scsi=on|off`` (since 5.0) |
307 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
41fba161 PM |
308 | |
309 | The virtio-blk SCSI passthrough feature is a legacy VIRTIO feature. VIRTIO 1.0 | |
310 | and later do not support it because the virtio-scsi device was introduced for | |
311 | full SCSI support. Use virtio-scsi instead when SCSI passthrough is required. | |
312 | ||
313 | Note this also applies to ``-device virtio-blk-pci,scsi=on|off``, which is an | |
314 | alias. | |
315 | ||
36d83272 KJ |
316 | ``-device nvme-ns,eui64-default=on|off`` (since 7.1) |
317 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
318 | ||
319 | In QEMU versions 6.1, 6.2 and 7.0, the ``nvme-ns`` generates an EUI-64 | |
120f765e | 320 | identifier that is not globally unique. If an EUI-64 identifier is required, the |
36d83272 KJ |
321 | user must set it explicitly using the ``nvme-ns`` device parameter ``eui64``. |
322 | ||
8b1e59a6 KJ |
323 | ``-device nvme,use-intel-id=on|off`` (since 7.1) |
324 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
325 | ||
326 | The ``nvme`` device originally used a PCI Vendor/Device Identifier combination | |
327 | from Intel that was not properly allocated. Since version 5.2, the controller | |
328 | has used a properly allocated identifier. Deprecate the ``use-intel-id`` | |
329 | machine compatibility parameter. | |
330 | ||
7c8d295b | 331 | |
41fba161 PM |
332 | Block device options |
333 | '''''''''''''''''''' | |
334 | ||
e2cc363b YW |
335 | ``"backing": ""`` (since 2.12) |
336 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
41fba161 PM |
337 | |
338 | In order to prevent QEMU from automatically opening an image's backing | |
339 | chain, use ``"backing": null`` instead. | |
340 | ||
e2cc363b YW |
341 | ``rbd`` keyvalue pair encoded filenames: ``""`` (since 3.1) |
342 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
41fba161 PM |
343 | |
344 | Options for ``rbd`` should be specified according to its runtime options, | |
345 | like other block drivers. Legacy parsing of keyvalue pair encoded | |
346 | filenames is useful to open images with the old format for backing files; | |
347 | These image files should be updated to use the current format. | |
348 | ||
349 | Example of legacy encoding:: | |
350 | ||
351 | json:{"file.driver":"rbd", "file.filename":"rbd:rbd/name"} | |
352 | ||
353 | The above, converted to the current supported format:: | |
354 | ||
355 | json:{"file.driver":"rbd", "file.pool":"rbd", "file.image":"name"} | |
356 | ||
610783cb DB |
357 | ``iscsi,password=xxx`` (since 8.0) |
358 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
359 | ||
360 | Specifying the iSCSI password in plain text on the command line using the | |
361 | ``password`` option is insecure. The ``password-secret`` option should be | |
362 | used instead, to refer to a ``--object secret...`` instance that provides | |
363 | a password via a file, or encrypted. | |
364 | ||
41fba161 PM |
365 | Backwards compatibility |
366 | ----------------------- | |
367 | ||
e2cc363b YW |
368 | Runnability guarantee of CPU models (since 4.1) |
369 | ''''''''''''''''''''''''''''''''''''''''''''''' | |
41fba161 PM |
370 | |
371 | Previous versions of QEMU never changed existing CPU models in | |
372 | ways that introduced additional host software or hardware | |
373 | requirements to the VM. This allowed management software to | |
374 | safely change the machine type of an existing VM without | |
375 | introducing new requirements ("runnability guarantee"). This | |
376 | prevented CPU models from being updated to include CPU | |
377 | vulnerability mitigations, leaving guests vulnerable in the | |
378 | default configuration. | |
379 | ||
380 | The CPU model runnability guarantee won't apply anymore to | |
381 | existing CPU models. Management software that needs runnability | |
ac9574bc | 382 | guarantees must resolve the CPU model aliases using the |
41fba161 PM |
383 | ``alias-of`` field returned by the ``query-cpu-definitions`` QMP |
384 | command. | |
385 | ||
386 | While those guarantees are kept, the return value of | |
387 | ``query-cpu-definitions`` will have existing CPU model aliases | |
388 | point to a version that doesn't break runnability guarantees | |
389 | (specifically, version 1 of those CPU models). In future QEMU | |
390 | versions, aliases will point to newer CPU model versions | |
391 | depending on the machine type, so management software must | |
392 | resolve CPU model aliases before starting a virtual machine. | |
393 | ||
582a098e TH |
394 | QEMU guest agent |
395 | ---------------- | |
396 | ||
397 | ``--blacklist`` command line option (since 7.2) | |
398 | ''''''''''''''''''''''''''''''''''''''''''''''' | |
399 | ||
400 | ``--blacklist`` has been replaced by ``--block-rpcs`` (which is a better | |
401 | wording for what this option does). The short form ``-b`` still stays | |
402 | the same and thus is the preferred way for scripts that should run with | |
403 | both, older and future versions of QEMU. | |
404 | ||
405 | ``blacklist`` config file option (since 7.2) | |
406 | '''''''''''''''''''''''''''''''''''''''''''' | |
407 | ||
408 | The ``blacklist`` config file option has been renamed to ``block-rpcs`` | |
409 | (to be in sync with the renaming of the corresponding command line | |
410 | option). |