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qemu-deprecated.texi 9.2KB

  1. @node Deprecated features
  2. @appendix Deprecated features
  3. In general features are intended to be supported indefinitely once
  4. introduced into QEMU. In the event that a feature needs to be removed,
  5. it will be listed in this appendix. The feature will remain functional
  6. for 2 releases prior to actual removal. Deprecated features may also
  7. generate warnings on the console when QEMU starts up, or if activated
  8. via a monitor command, however, this is not a mandatory requirement.
  9. Prior to the 2.10.0 release there was no official policy on how
  10. long features would be deprecated prior to their removal, nor
  11. any documented list of which features were deprecated. Thus
  12. any features deprecated prior to 2.10.0 will be treated as if
  13. they were first deprecated in the 2.10.0 release.
  14. What follows is a list of all features currently marked as
  15. deprecated.
  16. @section System emulator command line arguments
  17. @subsection -machine enforce-config-section=on|off (since 3.1)
  18. The @option{enforce-config-section} parameter is replaced by the
  19. @option{-global migration.send-configuration=@var{on|off}} option.
  20. @subsection -no-kvm (since 1.3.0)
  21. The ``-no-kvm'' argument is now a synonym for setting
  22. ``-machine accel=tcg''.
  23. @subsection -usbdevice (since 2.10.0)
  24. The ``-usbdevice DEV'' argument is now a synonym for setting
  25. the ``-device usb-DEV'' argument instead. The deprecated syntax
  26. would automatically enable USB support on the machine type.
  27. If using the new syntax, USB support must be explicitly
  28. enabled via the ``-machine usb=on'' argument.
  29. @subsection -drive file=json:@{...@{'driver':'file'@}@} (since 3.0)
  30. The 'file' driver for drives is no longer appropriate for character or host
  31. devices and will only accept regular files (S_IFREG). The correct driver
  32. for these file types is 'host_cdrom' or 'host_device' as appropriate.
  33. @subsection -net ...,name=@var{name} (since 3.1)
  34. The @option{name} parameter of the @option{-net} option is a synonym
  35. for the @option{id} parameter, which should now be used instead.
  36. @subsection -smp (invalid topologies) (since 3.1)
  37. CPU topology properties should describe whole machine topology including
  38. possible CPUs.
  39. However, historically it was possible to start QEMU with an incorrect topology
  40. where @math{@var{n} <= @var{sockets} * @var{cores} * @var{threads} < @var{maxcpus}},
  41. which could lead to an incorrect topology enumeration by the guest.
  42. Support for invalid topologies will be removed, the user must ensure
  43. topologies described with -smp include all possible cpus, i.e.
  44. @math{@var{sockets} * @var{cores} * @var{threads} = @var{maxcpus}}.
  45. @subsection -vnc acl (since 4.0.0)
  46. The @code{acl} option to the @code{-vnc} argument has been replaced
  47. by the @code{tls-authz} and @code{sasl-authz} options.
  48. @subsection QEMU_AUDIO_ environment variables and -audio-help (since 4.0)
  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.
  53. @subsection -realtime (since 4.1)
  54. The @code{-realtime mlock=on|off} argument has been replaced by the
  55. @code{-overcommit mem-lock=on|off} argument.
  56. @subsection -virtfs_synth (since 4.1)
  57. The ``-virtfs_synth'' argument is now deprecated. Please use ``-fsdev synth''
  58. and ``-device virtio-9p-...'' instead.
  59. @section QEMU Machine Protocol (QMP) commands
  60. @subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)
  61. "autoload" parameter is now ignored. All bitmaps are automatically loaded
  62. from qcow2 images.
  63. @subsection query-block result field dirty-bitmaps[i].status (since 4.0)
  64. The ``status'' field of the ``BlockDirtyInfo'' structure, returned by
  65. the query-block command is deprecated. Two new boolean fields,
  66. ``recording'' and ``busy'' effectively replace it.
  67. @subsection query-cpus (since 2.12.0)
  68. The ``query-cpus'' command is replaced by the ``query-cpus-fast'' command.
  69. @subsection query-cpus-fast "arch" output member (since 3.0.0)
  70. The ``arch'' output member of the ``query-cpus-fast'' command is
  71. replaced by the ``target'' output member.
  72. @subsection cpu-add (since 4.0)
  73. Use ``device_add'' for hotplugging vCPUs instead of ``cpu-add''. See
  74. documentation of ``query-hotpluggable-cpus'' for additional
  75. details.
  76. @subsection query-events (since 4.0)
  77. The ``query-events'' command has been superseded by the more powerful
  78. and accurate ``query-qmp-schema'' command.
  79. @subsection chardev client socket with 'wait' option (since 4.0)
  80. Character devices creating sockets in client mode should not specify
  81. the 'wait' field, which is only applicable to sockets in server mode
  82. @section Human Monitor Protocol (HMP) commands
  83. @subsection The hub_id parameter of 'hostfwd_add' / 'hostfwd_remove' (since 3.1)
  84. The @option{[hub_id name]} parameter tuple of the 'hostfwd_add' and
  85. 'hostfwd_remove' HMP commands has been replaced by @option{netdev_id}.
  86. @subsection cpu-add (since 4.0)
  87. Use ``device_add'' for hotplugging vCPUs instead of ``cpu-add''. See
  88. documentation of ``query-hotpluggable-cpus'' for additional details.
  89. @subsection acl_show, acl_reset, acl_policy, acl_add, acl_remove (since 4.0.0)
  90. The ``acl_show'', ``acl_reset'', ``acl_policy'', ``acl_add'', and
  91. ``acl_remove'' commands are deprecated with no replacement. Authorization
  92. for VNC should be performed using the pluggable QAuthZ objects.
  93. @section System emulator CPUS
  94. @subsection RISC-V ISA CPUs (since 4.1)
  95. The RISC-V cpus with the ISA version in the CPU name have been depcreated. The
  96. four CPUs are: ``rv32gcsu-v1.9.1``, ``rv32gcsu-v1.10.0``, ``rv64gcsu-v1.9.1`` and
  97. ``rv64gcsu-v1.10.0``. Instead the version can be specified via the CPU ``priv_spec``
  98. option when using the ``rv32`` or ``rv64`` CPUs.
  99. @subsection RISC-V ISA CPUs (since 4.1)
  100. The RISC-V no MMU cpus have been depcreated. The two CPUs: ``rv32imacu-nommu`` and
  101. ``rv64imacu-nommu`` should no longer be used. Instead the MMU status can be specified
  102. via the CPU ``mmu`` option when using the ``rv32`` or ``rv64`` CPUs.
  103. @section System emulator devices
  104. @subsection bluetooth (since 3.1)
  105. The bluetooth subsystem is unmaintained since many years and likely bitrotten
  106. quite a bit. It will be removed without replacement unless some users speaks
  107. up at the @email{} mailing list with information about
  108. their usecases.
  109. @section System emulator machines
  110. @subsection pc-0.12, pc-0.13, pc-0.14 and pc-0.15 (since 4.0)
  111. These machine types are very old and likely can not be used for live migration
  112. from old QEMU versions anymore. A newer machine type should be used instead.
  113. @subsection prep (PowerPC) (since 3.1)
  114. This machine type uses an unmaintained firmware, broken in lots of ways,
  115. and unable to start post-2004 operating systems. 40p machine type should be
  116. used instead.
  117. @subsection spike_v1.9.1 and spike_v1.10 (since 4.1)
  118. The version specific Spike machines have been deprecated in favour of the
  119. generic ``spike`` machine. If you need to specify an older version of the RISC-V
  120. spec you can use the ``-cpu rv64gcsu,priv_spec=v1.9.1`` command line argument.
  121. @section Device options
  122. @subsection Block device options
  123. @subsubsection "backing": "" (since 2.12.0)
  124. In order to prevent QEMU from automatically opening an image's backing
  125. chain, use ``"backing": null'' instead.
  126. @subsubsection rbd keyvalue pair encoded filenames: "" (since 3.1.0)
  127. Options for ``rbd'' should be specified according to its runtime options,
  128. like other block drivers. Legacy parsing of keyvalue pair encoded
  129. filenames is useful to open images with the old format for backing files;
  130. These image files should be updated to use the current format.
  131. Example of legacy encoding:
  132. @code{json:@{"file.driver":"rbd", "file.filename":"rbd:rbd/name"@}}
  133. The above, converted to the current supported format:
  134. @code{json:@{"file.driver":"rbd", "file.pool":"rbd", "file.image":"name"@}}
  135. @section Related binaries
  136. @subsection qemu-nbd --partition (since 4.0.0)
  137. The ``qemu-nbd --partition $digit'' code (also spelled @option{-P})
  138. can only handle MBR partitions, and has never correctly handled
  139. logical partitions beyond partition 5. If you know the offset and
  140. length of the partition (perhaps by using @code{sfdisk} within the
  141. guest), you can achieve the effect of exporting just that subset of
  142. the disk by use of the @option{--image-opts} option with a raw
  143. blockdev using the @code{offset} and @code{size} parameters layered on
  144. top of any other existing blockdev. For example, if partition 1 is
  145. 100MiB long starting at 1MiB, the old command:
  146. @code{qemu-nbd -t -P 1 -f qcow2 file.qcow2}
  147. can be rewritten as:
  148. @code{qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.backing.driver=file,file.backing.filename=file.qcow2}
  149. Alternatively, the @code{nbdkit} project provides a more powerful
  150. partition filter on top of its nbd plugin, which can be used to select
  151. an arbitrary MBR or GPT partition on top of any other full-image NBD
  152. export. Using this to rewrite the above example results in:
  153. @code{qemu-nbd -t -k /tmp/sock -f qcow2 file.qcow2 &}
  154. @code{nbdkit -f --filter=partition nbd socket=/tmp/sock partition=1}
  155. Note that if you are exposing the export via /dev/nbd0, it is easier
  156. to just export the entire image and then mount only /dev/nbd0p1 than
  157. it is to reinvoke @command{qemu-nbd -c /dev/nbd0} limited to just a
  158. subset of the image.