1 @node Deprecated features
2 @appendix Deprecated features
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.
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.
17 What follows is a list of all features currently marked as
20 @section Build options
24 Previously QEMU has supported building against both SDL 1.2
25 and 2.0 series APIs. Support for the SDL 1.2 builds will be
26 discontinued, so maintainers should switch to using SDL 2.0,
29 @section System emulator command line arguments
31 @subsection -machine enforce-config-section=on|off (since 3.1)
33 The @option{enforce-config-section} parameter is replaced by the
34 @option{-global migration.send-configuration=@var{on|off}} option.
36 @subsection -no-kvm (since 1.3.0)
38 The ``-no-kvm'' argument is now a synonym for setting
39 ``-machine accel=tcg''.
41 @subsection -usbdevice (since 2.10.0)
43 The ``-usbdevice DEV'' argument is now a synonym for setting
44 the ``-device usb-DEV'' argument instead. The deprecated syntax
45 would automatically enable USB support on the machine type.
46 If using the new syntax, USB support must be explicitly
47 enabled via the ``-machine usb=on'' argument.
49 @subsection -fsdev handle (since 2.12.0)
51 The ``handle'' fsdev backend does not support symlinks and causes the 9p
52 filesystem in the guest to fail a fair amount of tests from the PJD POSIX
53 filesystem test suite. Also it requires the CAP_DAC_READ_SEARCH capability,
54 which is not the recommended way to run QEMU. This backend should not be
55 used and it will be removed with no replacement.
57 @subsection -no-frame (since 2.12.0)
59 The @code{--no-frame} argument works with SDL 1.2 only. The other user
60 interfaces never implemented this in the first place. So this will be
61 removed together with SDL 1.2 support.
63 @subsection -virtioconsole (since 3.0.0)
65 Option @option{-virtioconsole} has been replaced by
66 @option{-device virtconsole}.
68 @subsection -clock (since 3.0.0)
70 The @code{-clock} option is ignored since QEMU version 1.7.0. There is no
71 replacement since it is not needed anymore.
73 @subsection -enable-hax (since 3.0.0)
75 The @option{-enable-hax} option has been replaced by @option{-accel hax}.
76 Both options have been introduced in QEMU version 2.9.0.
78 @subsection -drive file=json:@{...@{'driver':'file'@}@} (since 3.0)
80 The 'file' driver for drives is no longer appropriate for character or host
81 devices and will only accept regular files (S_IFREG). The correct driver
82 for these file types is 'host_cdrom' or 'host_device' as appropriate.
84 @subsection -net ...,name=@var{name} (since 3.1)
86 The @option{name} parameter of the @option{-net} option is a synonym
87 for the @option{id} parameter, which should now be used instead.
89 @subsection -smp (invalid topologies) (since 3.1)
91 CPU topology properties should describe whole machine topology including
94 However, historically it was possible to start QEMU with an incorrect topology
95 where @math{@var{n} <= @var{sockets} * @var{cores} * @var{threads} < @var{maxcpus}},
96 which could lead to an incorrect topology enumeration by the guest.
97 Support for invalid topologies will be removed, the user must ensure
98 topologies described with -smp include all possible cpus, i.e.
99 @math{@var{sockets} * @var{cores} * @var{threads} = @var{maxcpus}}.
101 @section QEMU Machine Protocol (QMP) commands
103 @subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)
105 "autoload" parameter is now ignored. All bitmaps are automatically loaded
108 @subsection query-cpus (since 2.12.0)
110 The ``query-cpus'' command is replaced by the ``query-cpus-fast'' command.
112 @subsection query-cpus-fast "arch" output member (since 3.0.0)
114 The ``arch'' output member of the ``query-cpus-fast'' command is
115 replaced by the ``target'' output member.
117 @section System emulator human monitor commands
119 @subsection The hub_id parameter of 'hostfwd_add' / 'hostfwd_remove' (since 3.1)
121 The @option{[hub_id name]} parameter tuple of the 'hostfwd_add' and
122 'hostfwd_remove' HMP commands has been replaced by @option{netdev_id}.
124 @section System emulator devices
126 @subsection ivshmem (since 2.6.0)
128 The ``ivshmem'' device type is replaced by either the ``ivshmem-plain''
129 or ``ivshmem-doorbell`` device types.
131 @section System emulator machines
133 @subsection pc-0.10 and pc-0.11 (since 3.0)
135 These machine types are very old and likely can not be used for live migration
136 from old QEMU versions anymore. A newer machine type should be used instead.
138 @subsection prep (PowerPC) (since 3.1)
140 This machine type uses an unmaintained firmware, broken in lots of ways,
141 and unable to start post-2004 operating systems. 40p machine type should be
144 @section Device options
146 @subsection Block device options
148 @subsubsection "backing": "" (since 2.12.0)
150 In order to prevent QEMU from automatically opening an image's backing
151 chain, use ``"backing": null'' instead.
153 @subsubsection rbd keyvalue pair encoded filenames: "" (since 3.1.0)
155 Options for ``rbd'' should be specified according to its runtime options,
156 like other block drivers. Legacy parsing of keyvalue pair encoded
157 filenames is useful to open images with the old format for backing files;
158 These image files should be updated to use the current format.
160 Example of legacy encoding:
162 @code{json:@{"file.driver":"rbd", "file.filename":"rbd:rbd/name"@}}
164 The above, converted to the current supported format:
166 @code{json:@{"file.driver":"rbd", "file.pool":"rbd", "file.image":"name"@}}
168 @subsection vio-spapr-device device options
170 @subsubsection "irq": "" (since 3.0.0)
172 The ``irq'' property is obsoleted.