@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
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.
+
@section QEMU Machine Protocol (QMP) commands
@subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)
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.
it is to reinvoke @command{qemu-nbd -c /dev/nbd0} limited to just a
subset of the image.
+@subsection qemu-img convert -n -o (since 4.2.0)
+
+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.
+
@section Build system
@subsection Python 2 support (since 4.1.0)
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.
+
+@section Backwards compatibility
+
+@subsection 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.
projects / mirror_qemu.git / blobdiff