24e13a4dc1
This only makes sense conceptually when used with listener chardevs. Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
442 lines
16 KiB
ReStructuredText
442 lines
16 KiB
ReStructuredText
Deprecated features
|
|
===================
|
|
|
|
In general features are intended to be supported indefinitely once
|
|
introduced into QEMU. In the event that a feature needs to be removed,
|
|
it will be listed in this section. The feature will remain functional for the
|
|
release in which it was deprecated and one further release. After these two
|
|
releases, the feature is liable to be removed. Deprecated features may also
|
|
generate warnings on the console when QEMU starts up, or if activated via a
|
|
monitor command, however, this is not a mandatory requirement.
|
|
|
|
Prior to the 2.10.0 release there was no official policy on how
|
|
long features would be deprecated prior to their removal, nor
|
|
any documented list of which features were deprecated. Thus
|
|
any features deprecated prior to 2.10.0 will be treated as if
|
|
they were first deprecated in the 2.10.0 release.
|
|
|
|
What follows is a list of all features currently marked as
|
|
deprecated.
|
|
|
|
System emulator command line arguments
|
|
--------------------------------------
|
|
|
|
``-drive file=json:{...{'driver':'file'}}`` (since 3.0)
|
|
'''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
The 'file' driver for drives is no longer appropriate for character or host
|
|
devices and will only accept regular files (S_IFREG). The correct driver
|
|
for these file types is 'host_cdrom' or 'host_device' as appropriate.
|
|
|
|
``QEMU_AUDIO_`` environment variables and ``-audio-help`` (since 4.0)
|
|
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
The ``-audiodev`` argument is now the preferred way to specify audio
|
|
backend settings instead of environment variables. To ease migration to
|
|
the new format, the ``-audiodev-help`` option can be used to convert
|
|
the current values of the environment variables to ``-audiodev`` options.
|
|
|
|
Creating sound card devices and vnc without ``audiodev=`` property (since 4.2)
|
|
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
When not using the deprecated legacy audio config, each sound card
|
|
should specify an ``audiodev=`` property. Additionally, when using
|
|
vnc, you should specify an ``audiodev=`` property if you plan to
|
|
transmit audio through the VNC protocol.
|
|
|
|
Creating sound card devices using ``-soundhw`` (since 5.1)
|
|
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Sound card devices should be created using ``-device`` instead. The
|
|
names are the same for most devices. The exceptions are ``hda`` which
|
|
needs two devices (``-device intel-hda -device hda-duplex``) and
|
|
``pcspk`` which can be activated using ``-machine
|
|
pcspk-audiodev=<name>``.
|
|
|
|
RISC-V ``-bios`` (since 5.1)
|
|
''''''''''''''''''''''''''''
|
|
|
|
QEMU 4.1 introduced support for the -bios option in QEMU for RISC-V for the
|
|
RISC-V virt machine and sifive_u machine. QEMU 4.1 had no changes to the
|
|
default behaviour to avoid breakages.
|
|
|
|
QEMU 5.1 changes the default behaviour from ``-bios none`` to ``-bios default``.
|
|
|
|
QEMU 5.1 has three options:
|
|
1. ``-bios default`` - This is the current default behavior if no -bios option
|
|
is included. This option will load the default OpenSBI firmware automatically.
|
|
The firmware is included with the QEMU release and no user interaction is
|
|
required. All a user needs to do is specify the kernel they want to boot
|
|
with the -kernel option
|
|
2. ``-bios none`` - QEMU will not automatically load any firmware. It is up
|
|
to the user to load all the images they need.
|
|
3. ``-bios <file>`` - Tells QEMU to load the specified file as the firmwrae.
|
|
|
|
``Configuring floppies with ``-global``
|
|
'''''''''''''''''''''''''''''''''''''''
|
|
|
|
Use ``-device floppy,...`` instead:
|
|
::
|
|
|
|
-global isa-fdc.driveA=...
|
|
-global sysbus-fdc.driveA=...
|
|
-global SUNW,fdtwo.drive=...
|
|
|
|
become
|
|
::
|
|
|
|
-device floppy,unit=0,drive=...
|
|
|
|
and
|
|
::
|
|
|
|
-global isa-fdc.driveB=...
|
|
-global sysbus-fdc.driveB=...
|
|
|
|
become
|
|
::
|
|
|
|
-device floppy,unit=1,drive=...
|
|
|
|
``-drive`` with bogus interface type
|
|
''''''''''''''''''''''''''''''''''''
|
|
|
|
Drives with interface types other than ``if=none`` are for onboard
|
|
devices. It is possible to use drives the board doesn't pick up with
|
|
-device. This usage is now deprecated. Use ``if=none`` instead.
|
|
|
|
Short-form boolean options (since 6.0)
|
|
''''''''''''''''''''''''''''''''''''''
|
|
|
|
Boolean options such as ``share=on``/``share=off`` could be written
|
|
in short form as ``share`` and ``noshare``. This is now deprecated
|
|
and will cause a warning.
|
|
|
|
``delay`` option for socket character devices (since 6.0)
|
|
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
The replacement for the ``nodelay`` short-form boolean option is ``nodelay=on``
|
|
rather than ``delay=off``.
|
|
|
|
``--enable-fips`` (since 6.0)
|
|
'''''''''''''''''''''''''''''
|
|
|
|
This option restricts usage of certain cryptographic algorithms when
|
|
the host is operating in FIPS mode.
|
|
|
|
If FIPS compliance is required, QEMU should be built with the ``libgcrypt``
|
|
library enabled as a cryptography provider.
|
|
|
|
Neither the ``nettle`` library, or the built-in cryptography provider are
|
|
supported on FIPS enabled hosts.
|
|
|
|
``-writeconfig`` (since 6.0)
|
|
'''''''''''''''''''''''''''''
|
|
|
|
The ``-writeconfig`` option is not able to serialize the entire contents
|
|
of the QEMU command line. It is thus considered a failed experiment
|
|
and deprecated, with no current replacement.
|
|
|
|
Userspace local APIC with KVM (x86, since 6.0)
|
|
''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Using ``-M kernel-irqchip=off`` with x86 machine types that include a local
|
|
APIC is deprecated. The ``split`` setting is supported, as is using
|
|
``-M kernel-irqchip=off`` with the ISA PC machine type.
|
|
|
|
hexadecimal sizes with scaling multipliers (since 6.0)
|
|
''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Input parameters that take a size value should only use a size suffix
|
|
(such as 'k' or 'M') when the base is written in decimal, and not when
|
|
the value is hexadecimal. That is, '0x20M' is deprecated, and should
|
|
be written either as '32M' or as '0x2000000'.
|
|
|
|
``-spice password=string`` (since 6.0)
|
|
''''''''''''''''''''''''''''''''''''''
|
|
|
|
This option is insecure because the SPICE password remains visible in
|
|
the process listing. This is replaced by the new ``password-secret``
|
|
option which lets the password be securely provided on the command
|
|
line using a ``secret`` object instance.
|
|
|
|
QEMU Machine Protocol (QMP) commands
|
|
------------------------------------
|
|
|
|
``blockdev-open-tray``, ``blockdev-close-tray`` argument ``device`` (since 2.8.0)
|
|
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Use argument ``id`` instead.
|
|
|
|
``eject`` argument ``device`` (since 2.8.0)
|
|
'''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Use argument ``id`` instead.
|
|
|
|
``blockdev-change-medium`` argument ``device`` (since 2.8.0)
|
|
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Use argument ``id`` instead.
|
|
|
|
``block_set_io_throttle`` argument ``device`` (since 2.8.0)
|
|
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Use argument ``id`` instead.
|
|
|
|
``query-named-block-nodes`` result ``encryption_key_missing`` (since 2.10.0)
|
|
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Always false.
|
|
|
|
``query-block`` result ``inserted.encryption_key_missing`` (since 2.10.0)
|
|
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Always false.
|
|
|
|
``blockdev-add`` empty string argument ``backing`` (since 2.10.0)
|
|
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Use argument value ``null`` instead.
|
|
|
|
``block-commit`` arguments ``base`` and ``top`` (since 3.1.0)
|
|
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Use arguments ``base-node`` and ``top-node`` instead.
|
|
|
|
``object-add`` option ``props`` (since 5.0)
|
|
'''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Specify the properties for the object as top-level arguments instead.
|
|
|
|
``query-named-block-nodes`` and ``query-block`` result dirty-bitmaps[i].status (since 4.0)
|
|
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
The ``status`` field of the ``BlockDirtyInfo`` structure, returned by
|
|
these commands is deprecated. Two new boolean fields, ``recording`` and
|
|
``busy`` effectively replace it.
|
|
|
|
``query-block`` result field ``dirty-bitmaps`` (Since 4.2)
|
|
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
The ``dirty-bitmaps`` field of the ``BlockInfo`` structure, returned by
|
|
the query-block command is itself now deprecated. The ``dirty-bitmaps``
|
|
field of the ``BlockDeviceInfo`` struct should be used instead, which is the
|
|
type of the ``inserted`` field in query-block replies, as well as the
|
|
type of array items in query-named-block-nodes.
|
|
|
|
Since the ``dirty-bitmaps`` field is optionally present in both the old and
|
|
new locations, clients must use introspection to learn where to anticipate
|
|
the field if/when it does appear in command output.
|
|
|
|
``nbd-server-add`` and ``nbd-server-remove`` (since 5.2)
|
|
''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Use the more generic commands ``block-export-add`` and ``block-export-del``
|
|
instead. As part of this deprecation, where ``nbd-server-add`` used a
|
|
single ``bitmap``, the new ``block-export-add`` uses a list of ``bitmaps``.
|
|
|
|
System emulator CPUS
|
|
--------------------
|
|
|
|
``moxie`` CPU (since 5.2.0)
|
|
'''''''''''''''''''''''''''
|
|
|
|
The ``moxie`` guest CPU support is deprecated and will be removed in
|
|
a future version of QEMU. It's unclear whether anybody is still using
|
|
CPU emulation in QEMU, and there are no test images available to make
|
|
sure that the code is still working.
|
|
|
|
``lm32`` CPUs (since 5.2.0)
|
|
'''''''''''''''''''''''''''
|
|
|
|
The ``lm32`` guest CPU support is deprecated and will be removed in
|
|
a future version of QEMU. The only public user of this architecture
|
|
was the milkymist project, which has been dead for years; there was
|
|
never an upstream Linux port.
|
|
|
|
``unicore32`` CPUs (since 5.2.0)
|
|
''''''''''''''''''''''''''''''''
|
|
|
|
The ``unicore32`` guest CPU support is deprecated and will be removed in
|
|
a future version of QEMU. Support for this CPU was removed from the
|
|
upstream Linux kernel, and there is no available upstream toolchain
|
|
to build binaries for it.
|
|
|
|
``Icelake-Client`` CPU Model (since 5.2.0)
|
|
''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
``Icelake-Client`` CPU Models are deprecated. Use ``Icelake-Server`` CPU
|
|
Models instead.
|
|
|
|
MIPS ``I7200`` CPU Model (since 5.2)
|
|
''''''''''''''''''''''''''''''''''''
|
|
|
|
The ``I7200`` guest CPU relies on the nanoMIPS ISA, which is deprecated
|
|
(the ISA has never been upstreamed to a compiler toolchain). Therefore
|
|
this CPU is also deprecated.
|
|
|
|
System emulator devices
|
|
-----------------------
|
|
|
|
``ide-drive`` (since 4.2)
|
|
'''''''''''''''''''''''''
|
|
|
|
The 'ide-drive' device is deprecated. Users should use 'ide-hd' or
|
|
'ide-cd' as appropriate to get an IDE hard disk or CD-ROM as needed.
|
|
|
|
``scsi-disk`` (since 4.2)
|
|
'''''''''''''''''''''''''
|
|
|
|
The 'scsi-disk' device is deprecated. Users should use 'scsi-hd' or
|
|
'scsi-cd' as appropriate to get a SCSI hard disk or CD-ROM as needed.
|
|
|
|
System emulator machines
|
|
------------------------
|
|
|
|
Raspberry Pi ``raspi2`` and ``raspi3`` machines (since 5.2)
|
|
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
The Raspberry Pi machines come in various models (A, A+, B, B+). To be able
|
|
to distinguish which model QEMU is implementing, the ``raspi2`` and ``raspi3``
|
|
machines have been renamed ``raspi2b`` and ``raspi3b``.
|
|
|
|
Device options
|
|
--------------
|
|
|
|
Emulated device options
|
|
'''''''''''''''''''''''
|
|
|
|
``-device virtio-blk,scsi=on|off`` (since 5.0.0)
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
The virtio-blk SCSI passthrough feature is a legacy VIRTIO feature. VIRTIO 1.0
|
|
and later do not support it because the virtio-scsi device was introduced for
|
|
full SCSI support. Use virtio-scsi instead when SCSI passthrough is required.
|
|
|
|
Note this also applies to ``-device virtio-blk-pci,scsi=on|off``, which is an
|
|
alias.
|
|
|
|
Block device options
|
|
''''''''''''''''''''
|
|
|
|
``"backing": ""`` (since 2.12.0)
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
In order to prevent QEMU from automatically opening an image's backing
|
|
chain, use ``"backing": null`` instead.
|
|
|
|
``rbd`` keyvalue pair encoded filenames: ``""`` (since 3.1.0)
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
Options for ``rbd`` should be specified according to its runtime options,
|
|
like other block drivers. Legacy parsing of keyvalue pair encoded
|
|
filenames is useful to open images with the old format for backing files;
|
|
These image files should be updated to use the current format.
|
|
|
|
Example of legacy encoding::
|
|
|
|
json:{"file.driver":"rbd", "file.filename":"rbd:rbd/name"}
|
|
|
|
The above, converted to the current supported format::
|
|
|
|
json:{"file.driver":"rbd", "file.pool":"rbd", "file.image":"name"}
|
|
|
|
``sheepdog`` driver (since 5.2.0)
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
The ``sheepdog`` block device driver is deprecated. The corresponding upstream
|
|
server project is no longer actively maintained. Users are recommended to switch
|
|
to an alternative distributed block device driver such as RBD. The
|
|
``qemu-img convert`` command can be used to liberate existing data by moving
|
|
it out of sheepdog volumes into an alternative storage backend.
|
|
|
|
linux-user mode CPUs
|
|
--------------------
|
|
|
|
``ppc64abi32`` CPUs (since 5.2.0)
|
|
'''''''''''''''''''''''''''''''''
|
|
|
|
The ``ppc64abi32`` architecture has a number of issues which regularly
|
|
trip up our CI testing and is suspected to be quite broken. For that
|
|
reason the maintainers strongly suspect no one actually uses it.
|
|
|
|
MIPS ``I7200`` CPU (since 5.2)
|
|
''''''''''''''''''''''''''''''
|
|
|
|
The ``I7200`` guest CPU relies on the nanoMIPS ISA, which is deprecated
|
|
(the ISA has never been upstreamed to a compiler toolchain). Therefore
|
|
this CPU is also deprecated.
|
|
|
|
Related binaries
|
|
----------------
|
|
|
|
qemu-img amend to adjust backing file (since 5.1)
|
|
'''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
The use of ``qemu-img amend`` to modify the name or format of a qcow2
|
|
backing image is deprecated; this functionality was never fully
|
|
documented or tested, and interferes with other amend operations that
|
|
need access to the original backing image (such as deciding whether a
|
|
v3 zero cluster may be left unallocated when converting to a v2
|
|
image). Rather, any changes to the backing chain should be performed
|
|
with ``qemu-img rebase -u`` either before or after the remaining
|
|
changes being performed by amend, as appropriate.
|
|
|
|
qemu-img backing file without format (since 5.1)
|
|
''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
The use of ``qemu-img create``, ``qemu-img rebase``, or ``qemu-img
|
|
convert`` to create or modify an image that depends on a backing file
|
|
now recommends that an explicit backing format be provided. This is
|
|
for safety: if QEMU probes a different format than what you thought,
|
|
the data presented to the guest will be corrupt; similarly, presenting
|
|
a raw image to a guest allows a potential security exploit if a future
|
|
probe sees a non-raw image based on guest writes.
|
|
|
|
To avoid the warning message, or even future refusal to create an
|
|
unsafe image, you must pass ``-o backing_fmt=`` (or the shorthand
|
|
``-F`` during create) to specify the intended backing format. You may
|
|
use ``qemu-img rebase -u`` to retroactively add a backing format to an
|
|
existing image. However, be aware that there are already potential
|
|
security risks to blindly using ``qemu-img info`` to probe the format
|
|
of an untrusted backing image, when deciding what format to add into
|
|
an existing image.
|
|
|
|
Backwards compatibility
|
|
-----------------------
|
|
|
|
Runnability guarantee of CPU models (since 4.1.0)
|
|
'''''''''''''''''''''''''''''''''''''''''''''''''
|
|
|
|
Previous versions of QEMU never changed existing CPU models in
|
|
ways that introduced additional host software or hardware
|
|
requirements to the VM. This allowed management software to
|
|
safely change the machine type of an existing VM without
|
|
introducing new requirements ("runnability guarantee"). This
|
|
prevented CPU models from being updated to include CPU
|
|
vulnerability mitigations, leaving guests vulnerable in the
|
|
default configuration.
|
|
|
|
The CPU model runnability guarantee won't apply anymore to
|
|
existing CPU models. Management software that needs runnability
|
|
guarantees must resolve the CPU model aliases using the
|
|
``alias-of`` field returned by the ``query-cpu-definitions`` QMP
|
|
command.
|
|
|
|
While those guarantees are kept, the return value of
|
|
``query-cpu-definitions`` will have existing CPU model aliases
|
|
point to a version that doesn't break runnability guarantees
|
|
(specifically, version 1 of those CPU models). In future QEMU
|
|
versions, aliases will point to newer CPU model versions
|
|
depending on the machine type, so management software must
|
|
resolve CPU model aliases before starting a virtual machine.
|
|
|
|
Guest Emulator ISAs
|
|
-------------------
|
|
|
|
nanoMIPS ISA
|
|
''''''''''''
|
|
|
|
The ``nanoMIPS`` ISA has never been upstreamed to any compiler toolchain.
|
|
As it is hard to generate binaries for it, declare it deprecated.
|