Re: [PATCH v3 18/33] docs/system: convert the documentation of deprecated features to rST.

["Alex Bennée" <alex.bennee@linaro.org>]

Peter Maydell <peter.maydell@linaro.org> writes:

> We put the whole of this document into the system manual, though
> technically a few parts of it apply to qemu-img or qemu-nbd which are
> otherwise documented in tools/.
>
> We only make formatting fixes, except for one use of 'appendix' which
> we change to 'section' because this isn't an appendix in the Sphinx
> manual.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Message-id: 20200226113034.6741-18-pbonzini@redhat.com

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

> ---
>  docs/system/deprecated.rst | 446 +++++++++++++++++++++++++++++++++++++
>  docs/system/index.rst      |   1 +
>  2 files changed, 447 insertions(+)
>  create mode 100644 docs/system/deprecated.rst
>
> diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst
> new file mode 100644
> index 00000000000..1eaa559079b
> --- /dev/null
> +++ b/docs/system/deprecated.rst
> @@ -0,0 +1,446 @@
> +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 2 releases prior to actual removal. 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
> +--------------------------------------
> +
> +``-machine enforce-config-section=on|off`` (since 3.1)
> +''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +The ``enforce-config-section`` parameter is replaced by the
> +``-global migration.send-configuration={on|off}`` option.
> +
> +``-no-kvm`` (since 1.3.0)
> +'''''''''''''''''''''''''
> +
> +The ``-no-kvm`` argument is now a synonym for setting ``-accel tcg``.
> +
> +``-usbdevice`` (since 2.10.0)
> +'''''''''''''''''''''''''''''
> +
> +The ``-usbdevice DEV`` argument is now a synonym for setting
> +the ``-device usb-DEV`` argument instead. The deprecated syntax
> +would automatically enable USB support on the machine type.
> +If using the new syntax, USB support must be explicitly
> +enabled via the ``-machine usb=on`` argument.
> +
> +``-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.
> +
> +``-net ...,name=``\ *name* (since 3.1)
> +''''''''''''''''''''''''''''''''''''''
> +
> +The ``name`` parameter of the ``-net`` option is a synonym
> +for the ``id`` parameter, which should now be used instead.
> +
> +``-smp`` (invalid topologies) (since 3.1)
> +'''''''''''''''''''''''''''''''''''''''''
> +
> +CPU topology properties should describe whole machine topology including
> +possible CPUs.
> +
> +However, historically it was possible to start QEMU with an incorrect topology
> +where *n* <= *sockets* * *cores* * *threads* < *maxcpus*,
> +which could lead to an incorrect topology enumeration by the guest.
> +Support for invalid topologies will be removed, the user must ensure
> +topologies described with -smp include all possible cpus, i.e.
> +*sockets* * *cores* * *threads* = *maxcpus*.
> +
> +``-vnc acl`` (since 4.0.0)
> +''''''''''''''''''''''''''
> +
> +The ``acl`` option to the ``-vnc`` argument has been replaced
> +by the ``tls-authz`` and ``sasl-authz`` options.
> +
> +``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=`` propery if you plan to
> +transmit audio through the VNC protocol.
> +
> +``-mon ...,control=readline,pretty=on|off`` (since 4.1)
> +'''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +The ``pretty=on|off`` switch has no effect for HMP monitors, but is
> +silently ignored. Using the switch with HMP monitors will become an
> +error in the future.
> +
> +``-realtime`` (since 4.1)
> +'''''''''''''''''''''''''
> +
> +The ``-realtime mlock=on|off`` argument has been replaced by the
> +``-overcommit mem-lock=on|off`` argument.
> +
> +``-numa node,mem=``\ *size* (since 4.1)
> +'''''''''''''''''''''''''''''''''''''''
> +
> +The parameter ``mem`` of ``-numa node`` is used to assign a part of
> +guest RAM to a NUMA node. But when using it, it's impossible to manage specified
> +RAM chunk on the host side (like bind it to a host node, setting bind policy, ...),
> +so guest end-ups with the fake NUMA configuration with suboptiomal performance.
> +However since 2014 there is an alternative way to assign RAM to a NUMA node
> +using parameter ``memdev``, which does the same as ``mem`` and adds
> +means to actualy manage node RAM on the host side. Use parameter ``memdev``
> +with *memory-backend-ram* backend as an replacement for parameter ``mem``
> +to achieve the same fake NUMA effect or a properly configured
> +*memory-backend-file* backend to actually benefit from NUMA configuration.
> +In future new machine versions will not accept the option but it will still
> +work with old machine types. User can check QAPI schema to see if the legacy
> +option is supported by looking at MachineInfo::numa-mem-supported property.
> +
> +``-numa`` node (without memory specified) (since 4.1)
> +'''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +Splitting RAM by default between NUMA nodes has the same issues as ``mem``
> +parameter described above with the difference that the role of the user plays
> +QEMU using implicit generic or board specific splitting rule.
> +Use ``memdev`` with *memory-backend-ram* backend or ``mem`` (if
> +it's supported by used machine type) to define mapping explictly instead.
> +
> +``-mem-path`` fallback to RAM (since 4.1)
> +'''''''''''''''''''''''''''''''''''''''''
> +
> +Currently if guest RAM allocation from file pointed by ``mem-path``
> +fails, QEMU falls back to allocating from RAM, which might result
> +in unpredictable behavior since the backing file specified by the user
> +is ignored. In the future, users will be responsible for making sure
> +the backing storage specified with ``-mem-path`` can actually provide
> +the guest RAM configured with ``-m`` and QEMU will fail to start up if
> +RAM allocation is unsuccessful.
> +
> +RISC-V ``-bios`` (since 4.1)
> +''''''''''''''''''''''''''''
> +
> +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 has no changes to the default behaviour to avoid breakages. This
> +default will change in a future QEMU release, so please prepare now. All users
> +of the virt or sifive_u machine must change their command line usage.
> +
> +QEMU 4.1 has three options, please migrate to one of these three:
> + 1. ``-bios none`` - This is the current default behavior if no -bios option
> +      is included. QEMU will not automatically load any firmware. It is up
> +      to the user to load all the images they need.
> + 2. ``-bios default`` - In a future QEMU release this will become the default
> +      behaviour if no -bios option is specified. 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
> + 3. ``-bios <file>`` - Tells QEMU to load the specified file as the firmwrae.
> +
> +``-tb-size`` option (since 5.0)
> +'''''''''''''''''''''''''''''''
> +
> +QEMU 5.0 introduced an alternative syntax to specify the size of the translation
> +block cache, ``-accel tcg,tb-size=``.  The new syntax deprecates the
> +previously available ``-tb-size`` option.
> +
> +``-show-cursor`` option (since 5.0)
> +'''''''''''''''''''''''''''''''''''
> +
> +Use ``-display sdl,show-cursor=on`` or
> + ``-display gtk,show-cursor=on`` instead.
> +
> +QEMU Machine Protocol (QMP) commands
> +------------------------------------
> +
> +``change`` (since 2.5.0)
> +''''''''''''''''''''''''
> +
> +Use ``blockdev-change-medium`` or ``change-vnc-password`` instead.
> +
> +``migrate_set_downtime`` and ``migrate_set_speed`` (since 2.8.0)
> +''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +Use ``migrate-set-parameters`` instead.
> +
> +``migrate-set-cache-size`` and ``query-migrate-cache-size`` (since 2.11.0)
> +''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +Use ``migrate-set-parameters`` and ``query-migrate-parameters`` instead.
> +
> +``query-block`` result field ``dirty-bitmaps[i].status`` (since 4.0)
> +''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +The ``status`` field of the ``BlockDirtyInfo`` structure, returned by
> +the query-block command 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.
> +
> +``query-cpus`` (since 2.12.0)
> +'''''''''''''''''''''''''''''
> +
> +The ``query-cpus`` command is replaced by the ``query-cpus-fast`` command.
> +
> +``query-cpus-fast`` ``arch`` output member (since 3.0.0)
> +''''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +The ``arch`` output member of the ``query-cpus-fast`` command is
> +replaced by the ``target`` output member.
> +
> +``cpu-add`` (since 4.0)
> +'''''''''''''''''''''''
> +
> +Use ``device_add`` for hotplugging vCPUs instead of ``cpu-add``.  See
> +documentation of ``query-hotpluggable-cpus`` for additional
> +details.
> +
> +``query-events`` (since 4.0)
> +''''''''''''''''''''''''''''
> +
> +The ``query-events`` command has been superseded by the more powerful
> +and accurate ``query-qmp-schema`` command.
> +
> +chardev client socket with ``wait`` option (since 4.0)
> +''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +Character devices creating sockets in client mode should not specify
> +the 'wait' field, which is only applicable to sockets in server mode
> +
> +Human Monitor Protocol (HMP) commands
> +-------------------------------------
> +
> +The ``hub_id`` parameter of ``hostfwd_add`` / ``hostfwd_remove`` (since 3.1)
> +''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +The ``[hub_id name]`` parameter tuple of the 'hostfwd_add' and
> +'hostfwd_remove' HMP commands has been replaced by ``netdev_id``.
> +
> +``cpu-add`` (since 4.0)
> +'''''''''''''''''''''''
> +
> +Use ``device_add`` for hotplugging vCPUs instead of ``cpu-add``.  See
> +documentation of ``query-hotpluggable-cpus`` for additional details.
> +
> +``acl_show``, ``acl_reset``, ``acl_policy``, ``acl_add``, ``acl_remove`` (since 4.0.0)
> +''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +The ``acl_show``, ``acl_reset``, ``acl_policy``, ``acl_add``, and
> +``acl_remove`` commands are deprecated with no replacement. Authorization
> +for VNC should be performed using the pluggable QAuthZ objects.
> +
> +Guest Emulator ISAs
> +-------------------
> +
> +RISC-V ISA privledge specification version 1.09.1 (since 4.1)
> +'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +The RISC-V ISA privledge specification version 1.09.1 has been deprecated.
> +QEMU supports both the newer version 1.10.0 and the ratified version 1.11.0, these
> +should be used instead of the 1.09.1 version.
> +
> +System emulator CPUS
> +--------------------
> +
> +RISC-V ISA CPUs (since 4.1)
> +'''''''''''''''''''''''''''
> +
> +The RISC-V cpus with the ISA version in the CPU name have been depcreated. The
> +four CPUs are: ``rv32gcsu-v1.9.1``, ``rv32gcsu-v1.10.0``, ``rv64gcsu-v1.9.1`` and
> +``rv64gcsu-v1.10.0``. Instead the version can be specified via the CPU ``priv_spec``
> +option when using the ``rv32`` or ``rv64`` CPUs.
> +
> +RISC-V ISA CPUs (since 4.1)
> +'''''''''''''''''''''''''''
> +
> +The RISC-V no MMU cpus have been depcreated. The two CPUs: ``rv32imacu-nommu`` and
> +``rv64imacu-nommu`` should no longer be used. Instead the MMU status can be specified
> +via the CPU ``mmu`` option when using the ``rv32`` or ``rv64`` CPUs.
> +
> +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
> +------------------------
> +
> +mips ``r4k`` platform (since 5.0)
> +'''''''''''''''''''''''''''''''''
> +
> +This machine type is very old and unmaintained. Users should use the ``malta``
> +machine type instead.
> +
> +``pc-1.0``, ``pc-1.1``, ``pc-1.2`` and ``pc-1.3`` (since 5.0)
> +'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +These machine types are very old and likely can not be used for live migration
> +from old QEMU versions anymore. A newer machine type should be used instead.
> +
> +``spike_v1.9.1`` and ``spike_v1.10`` (since 4.1)
> +''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +The version specific Spike machines have been deprecated in favour of the
> +generic ``spike`` machine. If you need to specify an older version of the RISC-V
> +spec you can use the ``-cpu rv64gcsu,priv_spec=v1.9.1`` command line argument.
> +
> +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"}
> +
> +Related binaries
> +----------------
> +
> +``qemu-img convert -n -o`` (since 4.2.0)
> +''''''''''''''''''''''''''''''''''''''''
> +
> +All options specified in ``-o`` are image creation options, so
> +they have no effect when used with ``-n`` to skip image creation.
> +Silently ignored options can be confusing, so this combination of
> +options will be made an error in future versions.
> +
> +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 te
> +``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.
> +
> +
> +Recently removed features
> +=========================
> +
> +What follows is a record of recently removed, formerly deprecated
> +features that serves as a record for users who have encountered
> +trouble after a recent upgrade.
> +
> +QEMU Machine Protocol (QMP) commands
> +------------------------------------
> +
> +``block-dirty-bitmap-add`` "autoload" parameter (since 4.2.0)
> +'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +The "autoload" parameter has been ignored since 2.12.0. All bitmaps
> +are automatically loaded from qcow2 images.
> +
> +Related binaries
> +----------------
> +
> +``qemu-nbd --partition`` (removed in 5.0.0)
> +'''''''''''''''''''''''''''''''''''''''''''
> +
> +The ``qemu-nbd --partition $digit`` code (also spelled ``-P``)
> +could only handle MBR partitions, and never correctly handled logical
> +partitions beyond partition 5.  Exporting a partition can still be
> +done by utilizing the ``--image-opts`` option with a raw blockdev
> +using the ``offset`` and ``size`` parameters layered on top of
> +any other existing blockdev. For example, if partition 1 is 100MiB
> +long starting at 1MiB, the old command::
> +
> +  qemu-nbd -t -P 1 -f qcow2 file.qcow2
> +
> +can be rewritten as::
> +
> +  qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.file.driver=file,file.file.filename=file.qcow2
> diff --git a/docs/system/index.rst b/docs/system/index.rst
> index d655344fffd..f2f29fb6d2c 100644
> --- a/docs/system/index.rst
> +++ b/docs/system/index.rst
> @@ -16,3 +16,4 @@ Contents:
>     managed-startup
>     security
>     vfio-ap
> +   deprecated


-- 
Alex Bennée