@subsection -no-kvm (since 1.3.0)
-The ``-no-kvm'' argument is now a synonym for setting
-``-machine accel=tcg''.
+The ``-no-kvm'' argument is now a synonym for setting ``-accel tcg''.
@subsection -usbdevice (since 2.10.0)
the new format, the ``-audiodev-help'' option can be used to convert
the current values of the environment variables to ``-audiodev'' options.
+@subsection 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 @code{audiodev=} property. Additionally, when using
+vnc, you should specify an @code{audiodev=} propery if you plan to
+transmit audio through the VNC protocol.
+
@subsection -mon ...,control=readline,pretty=on|off (since 4.1)
The @code{pretty=on|off} switch has no effect for HMP monitors, but is
The @code{-realtime mlock=on|off} argument has been replaced by the
@code{-overcommit mem-lock=on|off} argument.
-@subsection -virtfs_synth (since 4.1)
-
-The ``-virtfs_synth'' argument is now deprecated. Please use ``-fsdev synth''
-and ``-device virtio-9p-...'' instead.
-
@subsection -numa node,mem=@var{size} (since 4.1)
The parameter @option{mem} of @option{-numa node} is used to assign a part of
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.
+@subsection -numa node (without memory specified) (since 4.1)
+
+Splitting RAM by default between NUMA nodes has the same issues as @option{mem}
+parameter described above with the difference that the role of the user plays
+QEMU using implicit generic or board specific splitting rule.
+Use @option{memdev} with @var{memory-backend-ram} backend or @option{mem} (if
+it's supported by used machine type) to define mapping explictly instead.
+
+@subsection -mem-path fallback to RAM (since 4.1)
+Currently if guest RAM allocation from file pointed by @option{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 @option{-mem-path} can actually provide
+the guest RAM configured with @option{-m} and QEMU will fail to start up if
+RAM allocation is unsuccessful.
+
+@subsection 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.
+
+@subsection -tb-size option (since 5.0)
+
+QEMU 5.0 introduced an alternative syntax to specify the size of the translation
+block cache, @option{-accel tcg,tb-size=}. The new syntax deprecates the
+previously available @option{-tb-size} option.
+
@section QEMU Machine Protocol (QMP) commands
-@subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)
+@subsection change (since 2.5.0)
+
+Use ``blockdev-change-medium'' or ``change-vnc-password'' instead.
+
+@subsection migrate_set_downtime and migrate_set_speed (since 2.8.0)
-"autoload" parameter is now ignored. All bitmaps are automatically loaded
-from qcow2 images.
+Use ``migrate-set-parameters'' instead.
+
+@subsection migrate-set-cache-size and query-migrate-cache-size (since 2.11.0)
+
+Use ``migrate-set-parameters'' and ``query-migrate-parameters'' instead.
@subsection query-block result field dirty-bitmaps[i].status (since 4.0)
the query-block command is deprecated. Two new boolean fields,
``recording'' and ``busy'' effectively replace it.
+@subsection 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.
+
@subsection query-cpus (since 2.12.0)
The ``query-cpus'' command is replaced by the ``query-cpus-fast'' command.
@section System emulator devices
-@subsection bluetooth (since 3.1)
+@subsection 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.
-The bluetooth subsystem is unmaintained since many years and likely bitrotten
-quite a bit. It will be removed without replacement unless some users speaks
-up at the @email{qemu-devel@@nongnu.org} mailing list with information about
-their usecases.
+@subsection 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.
@section System emulator machines
-@subsection pc-0.12, pc-0.13, pc-0.14 and pc-0.15 (since 4.0)
+@subsection mips r4k platform (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.
+This machine type is very old and unmaintained. Users should use the 'malta'
+machine type instead.
-@subsection prep (PowerPC) (since 3.1)
+@subsection pc-1.0, pc-1.1, pc-1.2 and pc-1.3 (since 5.0)
-This machine type uses an unmaintained firmware, broken in lots of ways,
-and unable to start post-2004 operating systems. 40p machine type should be
-used instead.
+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.
@subsection spike_v1.9.1 and spike_v1.10 (since 4.1)
@section Device options
+@subsection Emulated device options
+
+@subsubsection -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.
+
@subsection Block device options
@subsubsection "backing": "" (since 2.12.0)
@section Related binaries
-@subsection qemu-nbd --partition (since 4.0.0)
+@subsection qemu-img convert -n -o (since 4.2.0)
-The ``qemu-nbd --partition $digit'' code (also spelled @option{-P})
-can only handle MBR partitions, and has never correctly handled
-logical partitions beyond partition 5. If you know the offset and
-length of the partition (perhaps by using @code{sfdisk} within the
-guest), you can achieve the effect of exporting just that subset of
-the disk by use of the @option{--image-opts} option with a raw
-blockdev using the @code{offset} and @code{size} parameters layered on
-top of any other existing blockdev. For example, if partition 1 is
-100MiB long starting at 1MiB, the old command:
+All options specified in @option{-o} are image creation options, so
+they have no effect when used with @option{-n} to skip image creation.
+Silently ignored options can be confusing, so this combination of
+options will be made an error in future versions.
-@code{qemu-nbd -t -P 1 -f qcow2 file.qcow2}
+@section Build system
-can be rewritten as:
+@subsection Python 2 support (since 4.1.0)
-@code{qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.backing.driver=file,file.backing.filename=file.qcow2}
+In the future, QEMU will require Python 3 to be available at
+build time. Support for Python 2 in scripts shipped with QEMU
+is deprecated.
-Alternatively, the @code{nbdkit} project provides a more powerful
-partition filter on top of its nbd plugin, which can be used to select
-an arbitrary MBR or GPT partition on top of any other full-image NBD
-export. Using this to rewrite the above example results in:
+@section Backwards compatibility
-@code{qemu-nbd -t -k /tmp/sock -f qcow2 file.qcow2 &}
-@code{nbdkit -f --filter=partition nbd socket=/tmp/sock partition=1}
+@subsection Runnability guarantee of CPU models (since 4.1.0)
-Note that if you are exposing the export via /dev/nbd0, it is easier
-to just export the entire image and then mount only /dev/nbd0p1 than
-it is to reinvoke @command{qemu-nbd -c /dev/nbd0} limited to just a
-subset of the image.
+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.
-@section Build system
+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.
-@subsection Python 2 support (since 4.1.0)
+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.
-In the future, QEMU will require Python 3 to be available at
-build time. Support for Python 2 in scripts shipped with QEMU
-is deprecated.
+
+@node Recently removed features
+@appendix 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.
+
+@section QEMU Machine Protocol (QMP) commands
+
+@subsection 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.
+
+@section Related binaries
+
+@subsection qemu-nbd --partition (removed in 5.0.0)
+
+The ``qemu-nbd --partition $digit'' code (also spelled @option{-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 @option{--image-opts} option with a raw blockdev
+using the @code{offset} and @code{size} parameters layered on top of
+any other existing blockdev. For example, if partition 1 is 100MiB
+long starting at 1MiB, the old command:
+
+@code{qemu-nbd -t -P 1 -f qcow2 file.qcow2}
+
+can be rewritten as:
+
+@code{qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.file.driver=file,file.file.filename=file.qcow2}
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