the new format, the ``-audiodev-help'' option can be used to convert
the current values of the environment variables to ``-audiodev'' options.
+@subsection -mon ...,control=readline,pretty=on|off (since 4.1)
+
+The @code{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.
+
+@subsection -realtime (since 4.1)
+
+The @code{-realtime mlock=on|off} argument has been replaced by the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
+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 @option{memdev}, which does the same as @option{mem} and adds
+means to actualy manage node RAM on the host side. Use parameter @option{memdev}
+with @var{memory-backend-ram} backend as an replacement for parameter @option{mem}
+to achieve the same fake NUMA effect or a properly configured
+@var{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.
+
+@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.
+
@section QEMU Machine Protocol (QMP) commands
@subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)
The ``query-events'' command has been superseded by the more powerful
and accurate ``query-qmp-schema'' command.
+@subsection 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
+
@section Human Monitor Protocol (HMP) commands
@subsection The hub_id parameter of 'hostfwd_add' / 'hostfwd_remove' (since 3.1)
``acl_remove'' commands are deprecated with no replacement. Authorization
for VNC should be performed using the pluggable QAuthZ objects.
+@section Guest Emulator ISAs
+
+@subsection 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.
+
+@section System emulator CPUS
+
+@subsection 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.
+
+@subsection 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.
+
@section System emulator devices
@subsection bluetooth (since 3.1)
and unable to start post-2004 operating systems. 40p machine type should be
used instead.
+@subsection 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.
+
@section Device options
@subsection Block device options
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.
+
+@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