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+.. _Deprecated features:
+
+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
+--------------------------------------
+
+``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.
+
+``-chardev`` backend aliases ``tty`` and ``parport`` (since 6.0)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+``tty`` and ``parport`` are aliases that will be removed. Instead, the
+actual backend names ``serial`` and ``parallel`` should be used.
+
+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``.
+
+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.
+
+``-smp`` ("parameter=0" SMP configurations) (since 6.2)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Specified CPU topology parameters must be greater than zero.
+
+In the SMP configuration, users should either provide a CPU topology
+parameter with a reasonable value (greater than zero) or just omit it
+and QEMU will compute the missing value.
+
+However, historically it was implicitly allowed for users to provide
+a parameter with zero value, which is meaningless and could also possibly
+cause unexpected results in the -smp parsing. So support for this kind of
+configurations (e.g. -smp 8,sockets=0) is deprecated since 6.2 and will
+be removed in the near future, users have to ensure that all the topology
+members described with -smp are greater than zero.
+
+Plugin argument passing through ``arg=<string>`` (since 6.1)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Passing TCG plugins arguments through ``arg=`` is redundant is makes the
+command-line less readable, especially when the argument itself consist of a
+name and a value, e.g. ``-plugin plugin_name,arg="arg_name=arg_value"``.
+Therefore, the usage of ``arg`` is redundant. Single-word arguments are treated
+as short-form boolean values, and passed to plugins as ``arg_name=on``.
+However, short-form booleans are deprecated and full explicit ``arg_name=on``
+form is preferred.
+
+``-drive if=none`` for the sifive_u OTP device (since 6.2)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Using ``-drive if=none`` to configure the OTP device of the sifive_u
+RISC-V machine is deprecated. Use ``-drive if=pflash`` instead.
+
+
+QEMU Machine Protocol (QMP) commands
+------------------------------------
+
+``blockdev-open-tray``, ``blockdev-close-tray`` argument ``device`` (since 2.8)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Use argument ``id`` instead.
+
+``eject`` argument ``device`` (since 2.8)
+'''''''''''''''''''''''''''''''''''''''''
+
+Use argument ``id`` instead.
+
+``blockdev-change-medium`` argument ``device`` (since 2.8)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Use argument ``id`` instead.
+
+``block_set_io_throttle`` argument ``device`` (since 2.8)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Use argument ``id`` instead.
+
+``blockdev-add`` empty string argument ``backing`` (since 2.10)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Use argument value ``null`` instead.
+
+``block-commit`` arguments ``base`` and ``top`` (since 3.1)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Use arguments ``base-node`` and ``top-node`` instead.
+
+``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``.
+
+``query-qmp-schema`` return value member ``values`` (since 6.2)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Member ``values`` in return value elements with meta-type ``enum`` is
+deprecated.  Use ``members`` instead.
+
+``drive-backup`` (since 6.2)
+''''''''''''''''''''''''''''
+
+Use ``blockdev-backup`` in combination with ``blockdev-add`` instead.
+This change primarily separates the creation/opening process of the backup
+target with explicit, separate steps. ``blockdev-backup`` uses mostly the
+same arguments as ``drive-backup``, except the ``format`` and ``mode``
+options are removed in favor of using explicit ``blockdev-create`` and
+``blockdev-add`` calls. See :doc:`/interop/live-block-operations` for
+details.
+
+Incorrectly typed ``device_add`` arguments (since 6.2)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Due to shortcomings in the internal implementation of ``device_add``, QEMU
+incorrectly accepts certain invalid arguments: Any object or list arguments are
+silently ignored. Other argument types are not checked, but an implicit
+conversion happens, so that e.g. string values can be assigned to integer
+device properties or vice versa.
+
+This is a bug in QEMU that will be fixed in the future so that previously
+accepted incorrect commands will return an error. Users should make sure that
+all arguments passed to ``device_add`` are consistent with the documented
+property types.
+
+``query-sgx`` return value member ``section-size`` (since 7.0)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Member ``section-size`` in return value elements with meta-type ``uint64`` is
+deprecated.  Use ``sections`` instead.
+
+
+``query-sgx-capabilities`` return value member ``section-size`` (since 7.0)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Member ``section-size`` in return value elements with meta-type ``uint64`` is
+deprecated.  Use ``sections`` instead.
+
+System accelerators
+-------------------
+
+MIPS ``Trap-and-Emul`` KVM support (since 6.0)
+''''''''''''''''''''''''''''''''''''''''''''''
+
+The MIPS ``Trap-and-Emul`` KVM host and guest support has been removed
+from Linux upstream kernel, declare it deprecated.
+
+Host Architectures
+------------------
+
+BE MIPS (since 7.2)
+'''''''''''''''''''
+
+As Debian 10 ("Buster") moved into LTS the big endian 32 bit version of
+MIPS moved out of support making it hard to maintain our
+cross-compilation CI tests of the architecture. As we no longer have
+CI coverage support may bitrot away before the deprecation process
+completes. The little endian variants of MIPS (both 32 and 64 bit) are
+still a supported host architecture.
+
+QEMU API (QAPI) events
+----------------------
+
+``MEM_UNPLUG_ERROR`` (since 6.2)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Use the more generic event ``DEVICE_UNPLUG_GUEST_ERROR`` instead.
+
+
+System emulator machines
+------------------------
+
+Arm ``virt`` machine ``dtb-kaslr-seed`` property
+''''''''''''''''''''''''''''''''''''''''''''''''
+
+The ``dtb-kaslr-seed`` property on the ``virt`` board has been
+deprecated; use the new name ``dtb-randomness`` instead. The new name
+better reflects the way this property affects all random data within
+the device tree blob, not just the ``kaslr-seed`` node.
+
+``pc-i440fx-1.4`` up to ``pc-i440fx-1.7`` (since 7.0)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+These old machine types are quite neglected nowadays and thus might have
+various pitfalls with regards to live migration. Use a newer machine type
+instead.
+
+
+Backend options
+---------------
+
+Using non-persistent backing file with pmem=on (since 6.1)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+This option is used when ``memory-backend-file`` is consumed by emulated NVDIMM
+device. However enabling ``memory-backend-file.pmem`` option, when backing file
+is (a) not DAX capable or (b) not on a filesystem that support direct mapping
+of persistent memory, is not safe and may lead to data loss or corruption in case
+of host crash.
+Options are:
+
+    - modify VM configuration to set ``pmem=off`` to continue using fake NVDIMM
+      (without persistence guaranties) with backing file on non DAX storage
+    - move backing file to NVDIMM storage and keep ``pmem=on``
+      (to have NVDIMM with persistence guaranties).
+
+Device options
+--------------
+
+Emulated device options
+'''''''''''''''''''''''
+
+``-device virtio-blk,scsi=on|off`` (since 5.0)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+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.
+
+``-device sga`` (since 6.2)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The ``sga`` device loads an option ROM for x86 targets which enables
+SeaBIOS to send messages to the serial console. SeaBIOS 1.11.0 onwards
+contains native support for this feature and thus use of the option
+ROM approach is obsolete. The native SeaBIOS support can be activated
+by using ``-machine graphics=off``.
+
+``-device nvme-ns,eui64-default=on|off`` (since 7.1)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+In QEMU versions 6.1, 6.2 and 7.0, the ``nvme-ns`` generates an EUI-64
+identifier that is not globally unique. If an EUI-64 identifier is required, the
+user must set it explicitly using the ``nvme-ns`` device parameter ``eui64``.
+
+``-device nvme,use-intel-id=on|off`` (since 7.1)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The ``nvme`` device originally used a PCI Vendor/Device Identifier combination
+from Intel that was not properly allocated. Since version 5.2, the controller
+has used a properly allocated identifier. Deprecate the ``use-intel-id``
+machine compatibility parameter.
+
+
+Block device options
+''''''''''''''''''''
+
+``"backing": ""`` (since 2.12)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+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)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+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"}
+
+Backwards compatibility
+-----------------------
+
+Runnability guarantee of CPU models (since 4.1)
+'''''''''''''''''''''''''''''''''''''''''''''''
+
+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.
+
+Tools
+-----
+
+virtiofsd
+'''''''''
+
+There is a new Rust implementation of ``virtiofsd`` at
+``https://gitlab.com/virtio-fs/virtiofsd``;
+since this is now marked stable, new development should be done on that
+rather than the existing C version in the QEMU tree.
+The C version will still accept fixes and patches that
+are already in development for the moment, but will eventually
+be deleted from this tree.
+New deployments should use the Rust version, and existing systems
+should consider moving to it.  The command line and feature set
+is very close and moving should be simple.
+
+
+QEMU guest agent
+----------------
+
+``--blacklist`` command line option (since 7.2)
+'''''''''''''''''''''''''''''''''''''''''''''''
+
+``--blacklist`` has been replaced by ``--block-rpcs`` (which is a better
+wording for what this option does). The short form ``-b`` still stays
+the same and thus is the preferred way for scripts that should run with
+both, older and future versions of QEMU.
+
+``blacklist`` config file option (since 7.2)
+''''''''''''''''''''''''''''''''''''''''''''
+
+The ``blacklist`` config file option has been renamed to ``block-rpcs``
+(to be in sync with the renaming of the corresponding command line
+option).