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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 | ||
23 | System emulator command line arguments | |
24 | -------------------------------------- | |
25 | ||
ccd3b3b8 PB |
26 | Short-form boolean options (since 6.0) |
27 | '''''''''''''''''''''''''''''''''''''' | |
28 | ||
29 | Boolean options such as ``share=on``/``share=off`` could be written | |
30 | in short form as ``share`` and ``noshare``. This is now deprecated | |
31 | and will cause a warning. | |
a1b40bda | 32 | |
fe636424 PB |
33 | ``delay`` option for socket character devices (since 6.0) |
34 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
35 | ||
36 | The replacement for the ``nodelay`` short-form boolean option is ``nodelay=on`` | |
37 | rather than ``delay=off``. | |
38 | ||
67f14574 MM |
39 | Plugin argument passing through ``arg=<string>`` (since 6.1) |
40 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
41 | ||
42 | Passing TCG plugins arguments through ``arg=`` is redundant is makes the | |
43 | command-line less readable, especially when the argument itself consist of a | |
44 | name and a value, e.g. ``-plugin plugin_name,arg="arg_name=arg_value"``. | |
45 | Therefore, the usage of ``arg`` is redundant. Single-word arguments are treated | |
46 | as short-form boolean values, and passed to plugins as ``arg_name=on``. | |
47 | However, short-form booleans are deprecated and full explicit ``arg_name=on`` | |
48 | form is preferred. | |
49 | ||
01e44980 RH |
50 | User-mode emulator command line arguments |
51 | ----------------------------------------- | |
52 | ||
53 | ``-p`` (since 9.0) | |
54 | '''''''''''''''''' | |
55 | ||
56 | The ``-p`` option pretends to control the host page size. However, | |
57 | it is not possible to change the host page size, and using the | |
58 | option only causes failures. | |
59 | ||
41fba161 PM |
60 | QEMU Machine Protocol (QMP) commands |
61 | ------------------------------------ | |
62 | ||
e2cc363b YW |
63 | ``blockdev-open-tray``, ``blockdev-close-tray`` argument ``device`` (since 2.8) |
64 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
73756ae3 MA |
65 | |
66 | Use argument ``id`` instead. | |
67 | ||
e2cc363b YW |
68 | ``eject`` argument ``device`` (since 2.8) |
69 | ''''''''''''''''''''''''''''''''''''''''' | |
73756ae3 MA |
70 | |
71 | Use argument ``id`` instead. | |
72 | ||
e2cc363b YW |
73 | ``blockdev-change-medium`` argument ``device`` (since 2.8) |
74 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
73756ae3 MA |
75 | |
76 | Use argument ``id`` instead. | |
77 | ||
e2cc363b YW |
78 | ``block_set_io_throttle`` argument ``device`` (since 2.8) |
79 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
73756ae3 MA |
80 | |
81 | Use argument ``id`` instead. | |
82 | ||
e2cc363b YW |
83 | ``blockdev-add`` empty string argument ``backing`` (since 2.10) |
84 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
73756ae3 MA |
85 | |
86 | Use argument value ``null`` instead. | |
87 | ||
e2cc363b YW |
88 | ``block-commit`` arguments ``base`` and ``top`` (since 3.1) |
89 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
73756ae3 MA |
90 | |
91 | Use arguments ``base-node`` and ``top-node`` instead. | |
92 | ||
443127e8 KW |
93 | ``nbd-server-add`` and ``nbd-server-remove`` (since 5.2) |
94 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
95 | ||
96 | Use the more generic commands ``block-export-add`` and ``block-export-del`` | |
cbad81ce EB |
97 | instead. As part of this deprecation, where ``nbd-server-add`` used a |
98 | single ``bitmap``, the new ``block-export-add`` uses a list of ``bitmaps``. | |
443127e8 | 99 | |
75ecee72 MA |
100 | ``query-qmp-schema`` return value member ``values`` (since 6.2) |
101 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
102 | ||
103 | Member ``values`` in return value elements with meta-type ``enum`` is | |
104 | deprecated. Use ``members`` instead. | |
105 | ||
1084159b VSO |
106 | ``drive-backup`` (since 6.2) |
107 | '''''''''''''''''''''''''''' | |
108 | ||
109 | Use ``blockdev-backup`` in combination with ``blockdev-add`` instead. | |
110 | This change primarily separates the creation/opening process of the backup | |
111 | target with explicit, separate steps. ``blockdev-backup`` uses mostly the | |
112 | same arguments as ``drive-backup``, except the ``format`` and ``mode`` | |
113 | options are removed in favor of using explicit ``blockdev-create`` and | |
114 | ``blockdev-add`` calls. See :doc:`/interop/live-block-operations` for | |
115 | details. | |
116 | ||
4d8b0f0a KW |
117 | Incorrectly typed ``device_add`` arguments (since 6.2) |
118 | '''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
119 | ||
120 | Due to shortcomings in the internal implementation of ``device_add``, QEMU | |
121 | incorrectly accepts certain invalid arguments: Any object or list arguments are | |
122 | silently ignored. Other argument types are not checked, but an implicit | |
123 | conversion happens, so that e.g. string values can be assigned to integer | |
124 | device properties or vice versa. | |
125 | ||
126 | This is a bug in QEMU that will be fixed in the future so that previously | |
127 | accepted incorrect commands will return an error. Users should make sure that | |
128 | all arguments passed to ``device_add`` are consistent with the documented | |
129 | property types. | |
130 | ||
1a8fc850 AB |
131 | QEMU Machine Protocol (QMP) events |
132 | ---------------------------------- | |
133 | ||
134 | ``MEM_UNPLUG_ERROR`` (since 6.2) | |
135 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
136 | ||
137 | Use the more generic event ``DEVICE_UNPLUG_GUEST_ERROR`` instead. | |
138 | ||
5485e52a AB |
139 | ``vcpu`` trace events (since 8.1) |
140 | ''''''''''''''''''''''''''''''''' | |
141 | ||
142 | The ability to instrument QEMU helper functions with vCPU-aware trace | |
143 | points was removed in 7.0. However QMP still exposed the vcpu | |
144 | parameter. This argument has now been deprecated and the remaining | |
145 | remaining trace points that used it are selected just by name. | |
1a8fc850 | 146 | |
54ab3c3f AB |
147 | Host Architectures |
148 | ------------------ | |
149 | ||
150 | BE MIPS (since 7.2) | |
151 | ''''''''''''''''''' | |
152 | ||
153 | As Debian 10 ("Buster") moved into LTS the big endian 32 bit version of | |
154 | MIPS moved out of support making it hard to maintain our | |
155 | cross-compilation CI tests of the architecture. As we no longer have | |
156 | CI coverage support may bitrot away before the deprecation process | |
157 | completes. The little endian variants of MIPS (both 32 and 64 bit) are | |
158 | still a supported host architecture. | |
159 | ||
5c27baf9 TH |
160 | System emulation on 32-bit x86 hosts (since 8.0) |
161 | '''''''''''''''''''''''''''''''''''''''''''''''' | |
162 | ||
163 | Support for 32-bit x86 host deployments is increasingly uncommon in mainstream | |
164 | OS distributions given the widespread availability of 64-bit x86 hardware. | |
165 | The QEMU project no longer considers 32-bit x86 support for system emulation to | |
166 | be an effective use of its limited resources, and thus intends to discontinue | |
167 | it. Since all recent x86 hardware from the past >10 years is capable of the | |
168 | 64-bit x86 extensions, a corresponding 64-bit OS should be used instead. | |
169 | ||
170 | ||
9997771b PMD |
171 | System emulator CPUs |
172 | -------------------- | |
173 | ||
174 | Nios II CPU (since 8.2) | |
175 | ''''''''''''''''''''''' | |
176 | ||
177 | The Nios II architecture is orphan. The ``nios2`` guest CPU support is | |
178 | deprecated and will be removed in a future version of QEMU. | |
179 | ||
6a41a621 TH |
180 | ``power5+`` and ``power7+`` CPU names (since 9.0) |
181 | ''''''''''''''''''''''''''''''''''''''''''''''''' | |
182 | ||
183 | The character "+" in device (and thus also CPU) names is not allowed | |
184 | in the QEMU object model anymore. ``power5+``, ``power5+_v2.1``, | |
185 | ``power7+`` and ``power7+_v2.1`` are currently still supported via | |
186 | an alias, but for consistency these will get removed in a future | |
187 | release, too. Use ``power5p_v2.1`` and ``power7p_v2.1`` instead. | |
188 | ||
c7bbef40 AB |
189 | CRIS CPU architecture (since 9.0) |
190 | ''''''''''''''''''''''''''''''''' | |
191 | ||
192 | The CRIS architecture was pulled from Linux in 4.17 and the compiler | |
193 | is no longer packaged in any distro making it harder to run the | |
194 | ``check-tcg`` tests. Unless we can improve the testing situation there | |
195 | is a chance the code will bitrot without anyone noticing. | |
9997771b | 196 | |
41fba161 PM |
197 | System emulator machines |
198 | ------------------------ | |
199 | ||
ac64ebbe PM |
200 | Arm ``virt`` machine ``dtb-kaslr-seed`` property (since 7.1) |
201 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
5242876f JD |
202 | |
203 | The ``dtb-kaslr-seed`` property on the ``virt`` board has been | |
204 | deprecated; use the new name ``dtb-randomness`` instead. The new name | |
205 | better reflects the way this property affects all random data within | |
206 | the device tree blob, not just the ``kaslr-seed`` node. | |
207 | ||
c7437f0d TH |
208 | ``pc-i440fx-2.0`` up to ``pc-i440fx-2.3`` (since 8.2) |
209 | ''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
210 | ||
211 | These old machine types are quite neglected nowadays and thus might have | |
212 | various pitfalls with regards to live migration. Use a newer machine type | |
213 | instead. | |
214 | ||
9997771b PMD |
215 | Nios II ``10m50-ghrd`` and ``nios2-generic-nommu`` machines (since 8.2) |
216 | ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
217 | ||
218 | The Nios II architecture is orphan. | |
219 | ||
322b038c ST |
220 | ``shix`` (since 9.0) |
221 | '''''''''''''''''''' | |
222 | ||
223 | The machine is no longer in existence and has been long unmaintained | |
c8cdec74 | 224 | in QEMU. This also holds for the TC51828 16MiB flash that it uses. |
c7437f0d | 225 | |
1392617d CLG |
226 | ``pseries-2.1`` up to ``pseries-2.11`` (since 9.0) |
227 | '''''''''''''''''''''''''''''''''''''''''''''''''' | |
228 | ||
229 | Older pseries machines before version 2.12 have undergone many changes | |
230 | to correct issues, mostly regarding migration compatibility. These are | |
231 | no longer maintained and removing them will make the code easier to | |
232 | read and maintain. Use versions 2.12 and above as a replacement. | |
233 | ||
cdcf766d IM |
234 | Backend options |
235 | --------------- | |
236 | ||
237 | Using non-persistent backing file with pmem=on (since 6.1) | |
238 | '''''''''''''''''''''''''''''''''''''''''''''''''''''''''' | |
239 | ||
240 | This option is used when ``memory-backend-file`` is consumed by emulated NVDIMM | |
241 | device. However enabling ``memory-backend-file.pmem`` option, when backing file | |
242 | is (a) not DAX capable or (b) not on a filesystem that support direct mapping | |
243 | of persistent memory, is not safe and may lead to data loss or corruption in case | |
244 | of host crash. | |
245 | Options are: | |
246 | ||
247 | - modify VM configuration to set ``pmem=off`` to continue using fake NVDIMM | |
248 | (without persistence guaranties) with backing file on non DAX storage | |
249 | - move backing file to NVDIMM storage and keep ``pmem=on`` | |
250 | (to have NVDIMM with persistence guaranties). | |
251 | ||
41fba161 PM |
252 | Device options |
253 | -------------- | |
254 | ||
255 | Emulated device options | |
256 | ''''''''''''''''''''''' | |
257 | ||
e2cc363b YW |
258 | ``-device virtio-blk,scsi=on|off`` (since 5.0) |
259 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
41fba161 PM |
260 | |
261 | The virtio-blk SCSI passthrough feature is a legacy VIRTIO feature. VIRTIO 1.0 | |
262 | and later do not support it because the virtio-scsi device was introduced for | |
263 | full SCSI support. Use virtio-scsi instead when SCSI passthrough is required. | |
264 | ||
265 | Note this also applies to ``-device virtio-blk-pci,scsi=on|off``, which is an | |
266 | alias. | |
267 | ||
36d83272 KJ |
268 | ``-device nvme-ns,eui64-default=on|off`` (since 7.1) |
269 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
270 | ||
271 | In QEMU versions 6.1, 6.2 and 7.0, the ``nvme-ns`` generates an EUI-64 | |
120f765e | 272 | identifier that is not globally unique. If an EUI-64 identifier is required, the |
36d83272 KJ |
273 | user must set it explicitly using the ``nvme-ns`` device parameter ``eui64``. |
274 | ||
8b1e59a6 KJ |
275 | ``-device nvme,use-intel-id=on|off`` (since 7.1) |
276 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
277 | ||
278 | The ``nvme`` device originally used a PCI Vendor/Device Identifier combination | |
279 | from Intel that was not properly allocated. Since version 5.2, the controller | |
280 | has used a properly allocated identifier. Deprecate the ``use-intel-id`` | |
281 | machine compatibility parameter. | |
282 | ||
adacc814 GP |
283 | ``-device cxl-type3,memdev=xxxx`` (since 8.0) |
284 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
285 | ||
286 | The ``cxl-type3`` device initially only used a single memory backend. With | |
287 | the addition of volatile memory support, it is now necessary to distinguish | |
288 | between persistent and volatile memory backends. As such, memdev is deprecated | |
289 | in favor of persistent-memdev. | |
290 | ||
71d72ece CS |
291 | ``-fsdev proxy`` and ``-virtfs proxy`` (since 8.1) |
292 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
293 | ||
294 | The 9p ``proxy`` filesystem backend driver has been deprecated and will be | |
295 | removed (along with its proxy helper daemon) in a future version of QEMU. Please | |
296 | use ``-fsdev local`` or ``-virtfs local`` for using the 9p ``local`` filesystem | |
297 | backend, or alternatively consider deploying virtiofsd instead. | |
298 | ||
299 | The 9p ``proxy`` backend was originally developed as an alternative to the 9p | |
300 | ``local`` backend. The idea was to enhance security by dispatching actual low | |
301 | level filesystem operations from 9p server (QEMU process) over to a separate | |
302 | process (the virtfs-proxy-helper binary). However this alternative never gained | |
303 | momentum. The proxy backend is much slower than the local backend, hasn't seen | |
304 | any development in years, and showed to be less secure, especially due to the | |
305 | fact that its helper daemon must be run as root, whereas with the local backend | |
306 | QEMU is typically run as unprivileged user and allows to tighten behaviour by | |
307 | mapping permissions et al by using its 'mapped' security model option. | |
308 | ||
309 | Nowadays it would make sense to reimplement the ``proxy`` backend by using | |
310 | QEMU's ``vhost`` feature, which would eliminate the high latency costs under | |
311 | which the 9p ``proxy`` backend currently suffers. However as of to date nobody | |
313e1629 | 312 | has indicated plans for such kind of reimplementation unfortunately. |
71d72ece | 313 | |
f57d5f80 DHB |
314 | RISC-V 'any' CPU type ``-cpu any`` (since 8.2) |
315 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
316 | ||
317 | The 'any' CPU type was introduced back in 2018 and has been around since the | |
318 | initial RISC-V QEMU port. Its usage has always been unclear: users don't know | |
319 | what to expect from a CPU called 'any', and in fact the CPU does not do anything | |
320 | special that isn't already done by the default CPUs rv32/rv64. | |
321 | ||
322 | After the introduction of the 'max' CPU type, RISC-V now has a good coverage | |
323 | of generic CPUs: rv32 and rv64 as default CPUs and 'max' as a feature complete | |
324 | CPU for both 32 and 64 bit builds. Users are then discouraged to use the 'any' | |
325 | CPU type starting in 8.2. | |
7c8d295b | 326 | |
8043effd DHB |
327 | RISC-V CPU properties which start with capital 'Z' (since 8.2) |
328 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
329 | ||
330 | All RISC-V CPU properties which start with capital 'Z' are being deprecated | |
331 | starting in 8.2. The reason is that they were wrongly added with capital 'Z' | |
332 | in the past. CPU properties were later added with lower-case names, which | |
333 | is the format we want to use from now on. | |
334 | ||
335 | Users which try to use these deprecated properties will receive a warning | |
336 | recommending to switch to their stable counterparts: | |
337 | ||
338 | - "Zifencei" should be replaced with "zifencei" | |
339 | - "Zicsr" should be replaced with "zicsr" | |
340 | - "Zihintntl" should be replaced with "zihintntl" | |
341 | - "Zihintpause" should be replaced with "zihintpause" | |
342 | - "Zawrs" should be replaced with "zawrs" | |
343 | - "Zfa" should be replaced with "zfa" | |
344 | - "Zfh" should be replaced with "zfh" | |
345 | - "Zfhmin" should be replaced with "zfhmin" | |
346 | - "Zve32f" should be replaced with "zve32f" | |
347 | - "Zve64f" should be replaced with "zve64f" | |
348 | - "Zve64d" should be replaced with "zve64d" | |
349 | ||
e9a54265 TH |
350 | ``-device pvrdma`` and the rdma subsystem (since 8.2) |
351 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
352 | ||
353 | The pvrdma device and the whole rdma subsystem are in a bad shape and | |
354 | without active maintenance. The QEMU project intends to remove this | |
355 | device and subsystem from the code base in a future release without | |
356 | replacement unless somebody steps up and improves the situation. | |
357 | ||
7c8d295b | 358 | |
41fba161 PM |
359 | Block device options |
360 | '''''''''''''''''''' | |
361 | ||
e2cc363b YW |
362 | ``"backing": ""`` (since 2.12) |
363 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
41fba161 PM |
364 | |
365 | In order to prevent QEMU from automatically opening an image's backing | |
366 | chain, use ``"backing": null`` instead. | |
367 | ||
e2cc363b YW |
368 | ``rbd`` keyvalue pair encoded filenames: ``""`` (since 3.1) |
369 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
41fba161 PM |
370 | |
371 | Options for ``rbd`` should be specified according to its runtime options, | |
372 | like other block drivers. Legacy parsing of keyvalue pair encoded | |
373 | filenames is useful to open images with the old format for backing files; | |
374 | These image files should be updated to use the current format. | |
375 | ||
376 | Example of legacy encoding:: | |
377 | ||
378 | json:{"file.driver":"rbd", "file.filename":"rbd:rbd/name"} | |
379 | ||
380 | The above, converted to the current supported format:: | |
381 | ||
382 | json:{"file.driver":"rbd", "file.pool":"rbd", "file.image":"name"} | |
383 | ||
610783cb DB |
384 | ``iscsi,password=xxx`` (since 8.0) |
385 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
386 | ||
387 | Specifying the iSCSI password in plain text on the command line using the | |
388 | ``password`` option is insecure. The ``password-secret`` option should be | |
389 | used instead, to refer to a ``--object secret...`` instance that provides | |
390 | a password via a file, or encrypted. | |
391 | ||
b04c1228 MA |
392 | Character device options |
393 | '''''''''''''''''''''''' | |
394 | ||
395 | Backend ``memory`` (since 9.0) | |
396 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
397 | ||
398 | ``memory`` is a deprecated synonym for ``ringbuf``. | |
399 | ||
bc5e8445 RB |
400 | CPU device properties |
401 | ''''''''''''''''''''' | |
402 | ||
403 | ``pmu-num=n`` on RISC-V CPUs (since 8.2) | |
404 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
405 | ||
406 | In order to support more flexible counter configurations this has been replaced | |
407 | by a ``pmu-mask`` property. If set of counters is continuous then the mask can | |
408 | be calculated with ``((2 ^ n) - 1) << 3``. The least significant three bits | |
409 | must be left clear. | |
410 | ||
411 | ||
41fba161 PM |
412 | Backwards compatibility |
413 | ----------------------- | |
414 | ||
e2cc363b YW |
415 | Runnability guarantee of CPU models (since 4.1) |
416 | ''''''''''''''''''''''''''''''''''''''''''''''' | |
41fba161 PM |
417 | |
418 | Previous versions of QEMU never changed existing CPU models in | |
419 | ways that introduced additional host software or hardware | |
420 | requirements to the VM. This allowed management software to | |
421 | safely change the machine type of an existing VM without | |
422 | introducing new requirements ("runnability guarantee"). This | |
423 | prevented CPU models from being updated to include CPU | |
424 | vulnerability mitigations, leaving guests vulnerable in the | |
425 | default configuration. | |
426 | ||
427 | The CPU model runnability guarantee won't apply anymore to | |
428 | existing CPU models. Management software that needs runnability | |
ac9574bc | 429 | guarantees must resolve the CPU model aliases using the |
41fba161 PM |
430 | ``alias-of`` field returned by the ``query-cpu-definitions`` QMP |
431 | command. | |
432 | ||
433 | While those guarantees are kept, the return value of | |
434 | ``query-cpu-definitions`` will have existing CPU model aliases | |
435 | point to a version that doesn't break runnability guarantees | |
436 | (specifically, version 1 of those CPU models). In future QEMU | |
437 | versions, aliases will point to newer CPU model versions | |
438 | depending on the machine type, so management software must | |
439 | resolve CPU model aliases before starting a virtual machine. | |
440 | ||
582a098e TH |
441 | QEMU guest agent |
442 | ---------------- | |
443 | ||
444 | ``--blacklist`` command line option (since 7.2) | |
445 | ''''''''''''''''''''''''''''''''''''''''''''''' | |
446 | ||
447 | ``--blacklist`` has been replaced by ``--block-rpcs`` (which is a better | |
448 | wording for what this option does). The short form ``-b`` still stays | |
449 | the same and thus is the preferred way for scripts that should run with | |
450 | both, older and future versions of QEMU. | |
451 | ||
452 | ``blacklist`` config file option (since 7.2) | |
453 | '''''''''''''''''''''''''''''''''''''''''''' | |
454 | ||
455 | The ``blacklist`` config file option has been renamed to ``block-rpcs`` | |
456 | (to be in sync with the renaming of the corresponding command line | |
457 | option). | |
7b24d326 JQ |
458 | |
459 | Migration | |
460 | --------- | |
461 | ||
462 | ``skipped`` MigrationStats field (since 8.1) | |
463 | '''''''''''''''''''''''''''''''''''''''''''' | |
464 | ||
465 | ``skipped`` field in Migration stats has been deprecated. It hasn't | |
466 | been used for more than 10 years. | |
467 | ||
40101f32 JQ |
468 | ``inc`` migrate command option (since 8.2) |
469 | '''''''''''''''''''''''''''''''''''''''''' | |
470 | ||
471 | Use blockdev-mirror with NBD instead. | |
472 | ||
473 | As an intermediate step the ``inc`` functionality can be achieved by | |
474 | setting the ``block-incremental`` migration parameter to ``true``. | |
475 | But this parameter is also deprecated. | |
8846b5bf JQ |
476 | |
477 | ``blk`` migrate command option (since 8.2) | |
478 | '''''''''''''''''''''''''''''''''''''''''' | |
479 | ||
480 | Use blockdev-mirror with NBD instead. | |
481 | ||
482 | As an intermediate step the ``blk`` functionality can be achieved by | |
483 | setting the ``block`` migration capability to ``true``. But this | |
484 | capability is also deprecated. | |
66db46ca JQ |
485 | |
486 | block migration (since 8.2) | |
487 | ''''''''''''''''''''''''''' | |
488 | ||
489 | Block migration is too inflexible. It needs to migrate all block | |
490 | devices or none. | |
491 | ||
492 | Please see "QMP invocation for live storage migration with | |
493 | ``blockdev-mirror`` + NBD" in docs/interop/live-block-operations.rst | |
494 | for a detailed explanation. | |
864128df JQ |
495 | |
496 | old compression method (since 8.2) | |
497 | '''''''''''''''''''''''''''''''''' | |
498 | ||
499 | Compression method fails too much. Too many races. We are going to | |
500 | remove it if nobody fixes it. For starters, migration-test | |
6477366f | 501 | compression tests are disabled because they fail randomly. If you need |
864128df | 502 | compression, use multifd compression methods. |