qemu-deprecated.texi

   1 @node Deprecated features
   2 @appendix Deprecated features
   3
   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 appendix. The feature will remain functional
   7 for 2 releases prior to actual removal. Deprecated features may also
   8 generate warnings on the console when QEMU starts up, or if activated
   9 via a monitor command, however, this is not a mandatory requirement.
  10
  11 Prior to the 2.10.0 release there was no official policy on how
  12 long features would be deprecated prior to their removal, nor
  13 any documented list of which features were deprecated. Thus
  14 any features deprecated prior to 2.10.0 will be treated as if
  15 they were first deprecated in the 2.10.0 release.
  16
  17 What follows is a list of all features currently marked as
  18 deprecated.
  19
  20 @section System emulator command line arguments
  21
  22 @subsection -machine enforce-config-section=on|off (since 3.1)
  23
  24 The @option{enforce-config-section} parameter is replaced by the
  25 @option{-global migration.send-configuration=@var{on|off}} option.
  26
  27 @subsection -no-kvm (since 1.3.0)
  28
  29 The ``-no-kvm'' argument is now a synonym for setting
  30 ``-machine accel=tcg''.
  31
  32 @subsection -usbdevice (since 2.10.0)
  33
  34 The ``-usbdevice DEV'' argument is now a synonym for setting
  35 the ``-device usb-DEV'' argument instead. The deprecated syntax
  36 would automatically enable USB support on the machine type.
  37 If using the new syntax, USB support must be explicitly
  38 enabled via the ``-machine usb=on'' argument.
  39
  40 @subsection -virtioconsole (since 3.0.0)
  41
  42 Option @option{-virtioconsole} has been replaced by
  43 @option{-device virtconsole}.
  44
  45 @subsection -no-frame (since 2.12.0)
  46
  47 The @code{--no-frame} argument works with SDL 1.2 only. The other user
  48 interfaces never implemented this in the first place. So this will be
  49 removed together with SDL 1.2 support.
  50 >>>>>>> remotes/bonzini/tags/for-upstream
  51
  52 @subsection -clock (since 3.0.0)
  53
  54 The @code{-clock} option is ignored since QEMU version 1.7.0. There is no
  55 replacement since it is not needed anymore.
  56
  57 @subsection -drive file=json:@{...@{'driver':'file'@}@} (since 3.0)
  58
  59 The 'file' driver for drives is no longer appropriate for character or host
  60 devices and will only accept regular files (S_IFREG). The correct driver
  61 for these file types is 'host_cdrom' or 'host_device' as appropriate.
  62
  63 @subsection -net ...,name=@var{name} (since 3.1)
  64
  65 The @option{name} parameter of the @option{-net} option is a synonym
  66 for the @option{id} parameter, which should now be used instead.
  67
  68 @subsection -smp (invalid topologies) (since 3.1)
  69
  70 CPU topology properties should describe whole machine topology including
  71 possible CPUs.
  72
  73 However, historically it was possible to start QEMU with an incorrect topology
  74 where @math{@var{n} <= @var{sockets} * @var{cores} * @var{threads} < @var{maxcpus}},
  75 which could lead to an incorrect topology enumeration by the guest.
  76 Support for invalid topologies will be removed, the user must ensure
  77 topologies described with -smp include all possible cpus, i.e.
  78   @math{@var{sockets} * @var{cores} * @var{threads} = @var{maxcpus}}.
  79
  80 @section QEMU Machine Protocol (QMP) commands
  81
  82 @subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)
  83
  84 "autoload" parameter is now ignored. All bitmaps are automatically loaded
  85 from qcow2 images.
  86
  87 @subsection query-cpus (since 2.12.0)
  88
  89 The ``query-cpus'' command is replaced by the ``query-cpus-fast'' command.
  90
  91 @subsection query-cpus-fast "arch" output member (since 3.0.0)
  92
  93 The ``arch'' output member of the ``query-cpus-fast'' command is
  94 replaced by the ``target'' output member.
  95
  96 @subsection cpu-add (since 4.0)
  97
  98 Use ``device_add'' for hotplugging vCPUs instead of ``cpu-add''.  See
  99 documentation of ``query-hotpluggable-cpus'' for additional
 100 details.
 101
 102 @section Human Monitor Protocol (HMP) commands
 103
 104 @subsection The hub_id parameter of 'hostfwd_add' / 'hostfwd_remove' (since 3.1)
 105
 106 The @option{[hub_id name]} parameter tuple of the 'hostfwd_add' and
 107 'hostfwd_remove' HMP commands has been replaced by @option{netdev_id}.
 108
 109 @subsection cpu-add (since 4.0)
 110
 111 Use ``device_add'' for hotplugging vCPUs instead of ``cpu-add''.  See
 112 documentation of ``query-hotpluggable-cpus'' for additional details.
 113
 114 @section System emulator devices
 115
 116 @subsection bluetooth (since 3.1)
 117
 118 The bluetooth subsystem is unmaintained since many years and likely bitrotten
 119 quite a bit. It will be removed without replacement unless some users speaks
 120 up at the @email{qemu-devel@@nongnu.org} mailing list with information about
 121 their usecases.
 122
 123 @section System emulator machines
 124
 125 @subsection pc-0.12, pc-0.13, pc-0.14 and pc-0.15 (since 4.0)
 126
 127 These machine types are very old and likely can not be used for live migration
 128 from old QEMU versions anymore. A newer machine type should be used instead.
 129
 130 @subsection prep (PowerPC) (since 3.1)
 131
 132 This machine type uses an unmaintained firmware, broken in lots of ways,
 133 and unable to start post-2004 operating systems. 40p machine type should be
 134 used instead.
 135
 136 @section Device options
 137
 138 @subsection Block device options
 139
 140 @subsubsection "backing": "" (since 2.12.0)
 141
 142 In order to prevent QEMU from automatically opening an image's backing
 143 chain, use ``"backing": null'' instead.
 144
 145 @subsubsection rbd keyvalue pair encoded filenames: "" (since 3.1.0)
 146
 147 Options for ``rbd'' should be specified according to its runtime options,
 148 like other block drivers.  Legacy parsing of keyvalue pair encoded
 149 filenames is useful to open images with the old format for backing files;
 150 These image files should be updated to use the current format.
 151
 152 Example of legacy encoding:
 153
 154 @code{json:@{"file.driver":"rbd", "file.filename":"rbd:rbd/name"@}}
 155
 156 The above, converted to the current supported format:
 157
 158 @code{json:@{"file.driver":"rbd", "file.pool":"rbd", "file.image":"name"@}}
 159
 160 @section Related binaries
 161
 162 @subsection qemu-nbd --partition (since 4.0.0)
 163
 164 The ``qemu-nbd --partition $digit'' code (also spelled @option{-P})
 165 can only handle MBR partitions, and has never correctly handled
 166 logical partitions beyond partition 5.  If you know the offset and
 167 length of the partition (perhaps by using @code{sfdisk} within the
 168 guest), you can achieve the effect of exporting just that subset of
 169 the disk by use of the @option{--image-opts} option with a raw
 170 blockdev using the @code{offset} and @code{size} parameters layered on
 171 top of any other existing blockdev. For example, if partition 1 is
 172 100MiB long starting at 1MiB, the old command:
 173
 174 @code{qemu-nbd -t -P 1 -f qcow2 file.qcow2}
 175
 176 can be rewritten as:
 177
 178 @code{qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.backing.driver=file,file.backing.filename=file.qcow2}
 179
 180 Alternatively, the @code{nbdkit} project provides a more powerful
 181 partition filter on top of its nbd plugin, which can be used to select
 182 an arbitrary MBR or GPT partition on top of any other full-image NBD
 183 export.  Using this to rewrite the above example results in:
 184
 185 @code{qemu-nbd -t -k /tmp/sock -f qcow2 file.qcow2 &}
 186 @code{nbdkit -f --filter=partition nbd socket=/tmp/sock partition=1}
 187
 188 Note that if you are exposing the export via /dev/nbd0, it is easier
 189 to just export the entire image and then mount only /dev/nbd0p1 than
 190 it is to reinvoke @command{qemu-nbd -c /dev/nbd0} limited to just a
 191 subset of the image.