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.

System emulator command line arguments

-hdachs (removed in 2.12)

The geometry defined by -hdachs c,h,s,t should now be specified via -device ide-hd,drive=dr,cyls=c,heads=h,secs=s,bios-chs-trans=t (together with -drive if=none,id=dr,...).

-net channel (removed in 2.12)

This option has been replaced by -net user,guestfwd=....

-net dump (removed in 2.12)

-net dump[,vlan=n][,file=filename][,len=maxlen] has been replaced by -object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=maxlen]. Note that the new syntax works with netdev IDs instead of the old “vlan” hubs.

-no-kvm-pit (removed in 2.12)

This was just a dummy option that has been ignored, since the in-kernel PIT cannot be disabled separately from the irqchip anymore. A similar effect (which also disables the KVM IOAPIC) can be obtained with -M kernel_irqchip=split.

-tdf (removed in 2.12)

There is no replacement, the -tdf option has just been ignored since the behaviour that could be changed by this option in qemu-kvm is now the default when using the KVM PIT. It still can be requested explicitly using -global kvm-pit.lost_tick_policy=delay.

-drive secs=s, -drive heads=h & -drive cyls=c (removed in 3.0)

The drive geometry should now be specified via -device ...,drive=dr,cyls=c,heads=h,secs=s (together with -drive if=none,id=dr,...).

-drive serial=, -drive trans= & -drive addr= (removed in 3.0)

Use -device ...,drive=dr,serial=r,bios-chs-trans=t,addr=a instead (together with -drive if=none,id=dr,...).

-net ...,vlan=x (removed in 3.0)

The term “vlan” was very confusing for most users in this context (it’s about specifying a hub ID, not about IEEE 802.1Q or something similar), so this has been removed. To connect one NIC frontend with a network backend, either use -nic ... (e.g. for on-board NICs) or use -netdev ...,id=n together with -device ...,netdev=n (for full control over pluggable NICs). To connect multiple NICs or network backends via a hub device (which is what vlan did), use -nic hubport,hubid=x,... or -netdev hubport,id=n,hubid=x,... (with -device ...,netdev=n) instead.

-no-kvm-irqchip (removed in 3.0)

Use -machine kernel_irqchip=off instead.

-no-kvm-pit-reinjection (removed in 3.0)

Use -global kvm-pit.lost_tick_policy=discard instead.

-balloon (removed in 3.1)

The -balloon virtio option has been replaced by -device virtio-balloon. The -balloon none option was a no-op and has no replacement.

-bootp (removed in 3.1)

The -bootp /some/file argument is replaced by either -netdev user,id=x,bootp=/some/file (for pluggable NICs, accompanied with -device ...,netdev=x), or -nic user,bootp=/some/file (for on-board NICs). The new syntax allows different settings to be provided per NIC.

-redir (removed in 3.1)

The -redir [tcp|udp]:hostport:[guestaddr]:guestport option is replaced by either -netdev user,id=x,hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport (for pluggable NICs, accompanied with -device ...,netdev=x) or by the option -nic user,hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport (for on-board NICs). The new syntax allows different settings to be provided per NIC.

-smb (removed in 3.1)

The -smb /some/dir argument is replaced by either -netdev user,id=x,smb=/some/dir (for pluggable NICs, accompanied with -device ...,netdev=x), or -nic user,smb=/some/dir (for on-board NICs). The new syntax allows different settings to be provided per NIC.

-tftp (removed in 3.1)

The -tftp /some/dir argument is replaced by either -netdev user,id=x,tftp=/some/dir (for pluggable NICs, accompanied with -device ...,netdev=x), or -nic user,tftp=/some/dir (for embedded NICs). The new syntax allows different settings to be provided per NIC.

-localtime (removed in 3.1)

Replaced by -rtc base=localtime.

-nodefconfig (removed in 3.1)

Use -no-user-config instead.

-rtc-td-hack (removed in 3.1)

Use -rtc driftfix=slew instead.

-startdate (removed in 3.1)

Replaced by -rtc base=date.

-vnc ...,tls=..., -vnc ...,x509=... & -vnc ...,x509verify=... (removed in 3.1)

The “tls-creds” option should be used instead to point to a “tls-creds-x509” object created using “-object”.

-mem-path fallback to RAM (removed in 5.0)

If guest RAM allocation from file pointed by mem-path failed, QEMU was falling back to allocating from RAM, which might have resulted in unpredictable behavior since the backing file specified by the user as ignored. Currently, users are responsible for making sure the backing storage specified with -mem-path can actually provide the guest RAM configured with -m and QEMU fails to start up if RAM allocation is unsuccessful.

-net ...,name=... (removed in 5.1)

The name parameter of the -net option was a synonym for the id parameter, which should now be used instead.

-numa node,mem=... (removed in 5.1)

The parameter mem of -numa node was used to assign a part of guest RAM to a NUMA node. But when using it, it’s impossible to manage a specified RAM chunk on the host side (like bind it to a host node, setting bind policy, …), so the guest ends up 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 actually manage node RAM on the host side. Use parameter memdev with memory-backend-ram backend as 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. New machine versions (since 5.1) will not accept the option but it will still work with old machine types. User can check the QAPI schema to see if the legacy option is supported by looking at MachineInfo::numa-mem-supported property.

-numa node (without memory specified) (removed in 5.2)

Splitting RAM by default between NUMA nodes had the same issues as mem parameter 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 explicitly instead. Users of existing VMs, wishing to preserve the same RAM distribution, should configure it explicitly using -numa node,memdev options. Current RAM distribution can be retrieved using HMP command info numa and if separate memory devices (pc|nv-dimm) are present use info memory-device and subtract device memory from output of info numa.

-smp (invalid topologies) (removed in 5.2)

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 is removed, the user must ensure topologies described with -smp include all possible cpus, i.e. sockets * cores * threads = maxcpus.

-machine enforce-config-section=on|off (removed in 5.2)

The enforce-config-section property was replaced by the -global migration.send-configuration={on|off} option.

-no-kvm (removed in 5.2)

The -no-kvm argument was a synonym for setting -machine accel=tcg.

-realtime (removed in 6.0)

The -realtime mlock=on|off argument has been replaced by the -overcommit mem-lock=on|off argument.

-show-cursor option (removed in 6.0)

Use -display sdl,show-cursor=on, -display gtk,show-cursor=on or -display default,show-cursor=on instead.

-tb-size option (removed in 6.0)

QEMU 5.0 introduced an alternative syntax to specify the size of the translation block cache, -accel tcg,tb-size=.

-usbdevice audio (removed in 6.0)

This option lacked the possibility to specify an audio backend device. Use -device usb-audio now instead (and specify a corresponding USB host controller or -usb if necessary).

-vnc acl (removed in 6.0)

The acl option to the -vnc argument has been replaced by the tls-authz and sasl-authz options.

-mon ...,control=readline,pretty=on|off (removed in 6.0)

The pretty=on|off switch has no effect for HMP monitors and its use is rejected.

-drive file=json:{...{'driver':'file'}} (removed in 6.0)

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.

Floppy controllers’ drive properties (removed in 6.0)

Use -device floppy,... instead. When configuring onboard floppy controllers

-global isa-fdc.driveA=...
-global sysbus-fdc.driveA=...
-global SUNW,fdtwo.drive=...

become

-device floppy,unit=0,drive=...

and

-global isa-fdc.driveB=...
-global sysbus-fdc.driveB=...

become

-device floppy,unit=1,drive=...

When plugging in a floppy controller

-device isa-fdc,...,driveA=...

becomes

-device isa-fdc,...
-device floppy,unit=0,drive=...

and

-device isa-fdc,...,driveB=...

becomes

-device isa-fdc,...
-device floppy,unit=1,drive=...

-drive with bogus interface type (removed in 6.0)

Drives with interface types other than if=none are for onboard devices. Drives the board doesn’t pick up can no longer be used with -device. Use if=none instead.

-usbdevice ccid (removed in 6.0)

This option was undocumented and not used in the field. Use -device usb-ccid instead.

RISC-V firmware not booted by default (removed in 5.1)

QEMU 5.1 changes the default behaviour from -bios none to -bios default for the RISC-V virt machine and sifive_u machine.

-no-quit (removed in 7.0)

The -no-quit was a synonym for -display ...,window-close=off which should be used instead.

--enable-fips (removed in 7.1)

This option restricted usage of certain cryptographic algorithms when the host is operating in FIPS mode.

If FIPS compliance is required, QEMU should be built with the libgcrypt or gnutls library enabled as a cryptography provider.

Neither the nettle library, or the built-in cryptography provider are supported on FIPS enabled hosts.

-writeconfig (removed in 7.1)

The -writeconfig option was not able to serialize the entire contents of the QEMU command line. It is thus considered a failed experiment and removed without a replacement.

loaded property of secret and TLS credential objects (removed in 9.2)

The loaded=on option in the command line or QMP object-add either had no effect (if loaded was the last option) or caused options to be effectively ignored as if they were not given. The property is therefore useless and has been removed.

opened property of rng-* objects (removed in 7.1)

The opened=on option in the command line or QMP object-add either had no effect (if opened was the last option) or caused errors. The property is therefore useless and should simply be removed.

-display sdl,window_close=... (removed in 7.1)

Use -display sdl,window-close=... instead (i.e. with a minus instead of an underscore between “window” and “close”).

-alt-grab and -display sdl,alt_grab=on (removed in 7.1)

Use -display sdl,grab-mod=lshift-lctrl-lalt instead.

-ctrl-grab and -display sdl,ctrl_grab=on (removed in 7.1)

Use -display sdl,grab-mod=rctrl instead.

-sdl (removed in 7.1)

Use -display sdl instead.

-curses (removed in 7.1)

Use -display curses instead.

Creating sound card devices using -soundhw (removed in 7.1)

Sound card devices should be created using -device or -audio. The exception is pcspk which can be activated using -machine pcspk-audiodev=<name>.

-watchdog (since 7.2)

Use -device instead.

Hexadecimal sizes with scaling multipliers (since 8.0)

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’ should be written either as ‘32M’ or as ‘0x2000000’.

-chardev backend aliases tty and parport (removed in 8.0)

tty and parport used to be aliases for serial and parallel respectively. The actual backend names should be used instead.

-drive if=none for the sifive_u OTP device (removed in 8.0)

Use -drive if=pflash to configure the OTP device of the sifive_u RISC-V machine instead.

-spice password=string (removed in 8.0)

This option was insecure because the SPICE password remained visible in the process listing. This was replaced by the new password-secret option which lets the password be securely provided on the command line using a secret object instance.

QEMU_AUDIO_ environment variables and -audio-help (removed in 8.2)

The -audiodev and -audio command line options are now the only way to specify audio backend settings.

Using -audiodev to define the default audio backend (removed in 8.2)

If no audiodev property is specified, previous versions would use the first -audiodev command line option as a fallback. Starting with version 8.2, audio backends created with -audiodev will only be used by clients (sound cards, machines with embedded sound hardware, VNC) that refer to it in an audiodev= property.

In order to configure a default audio backend, use the -audio command line option without specifying a model; while previous versions of QEMU required a model, starting with version 8.2 QEMU does not require a model and will not create any sound card in this case.

Note that the default audio backend must be configured on the command line if the -nodefaults options is used.

-no-hpet (removed in 9.0)

The HPET setting has been turned into a machine property. Use -machine hpet=off instead.

-no-acpi (removed in 9.0)

The -no-acpi setting has been turned into a machine property. Use -machine acpi=off instead.

-async-teardown (removed in 9.0)

Use -run-with async-teardown=on instead.

-chroot (removed in 9.0)

Use -run-with chroot=dir instead.

-singlestep (removed in 9.0)

The -singlestep option has been turned into an accelerator property, and given a name that better reflects what it actually does. Use -accel tcg,one-insn-per-tb=on instead.

-smp (“parameter=0” SMP configurations) (removed in 9.0)

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 removed since 9.0, users have to ensure that all the topology members described with -smp are greater than zero.

-global migration.decompress-error-check (removed in 9.1)

Removed along with the compression migration capability.

-device virtio-blk,scsi=on|off (since 9.1)

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.

-fsdev proxy and -virtfs proxy (since 9.2)

The 9p proxy filesystem backend driver was originally developed to enhance security by dispatching low level filesystem operations from 9p server (QEMU process) over to a separate process (the virtfs-proxy-helper binary). However the proxy backend was much slower than the local backend, didn’t see any development in years, and showed to be less secure, especially due to the fact that its helper daemon must be run as root.

Use local, possibly mapping permissions et al by using its ‘mapped’ security model option, or switch to virtiofs. The virtiofs daemon virtiofsd uses vhost to eliminate the high latency costs of the 9p proxy backend.

-portrait and -rotate (since 9.2)

The -portrait and -rotate options were documented as only working with the PXA LCD device, and all the machine types using that display device were removed in 9.2, so these options also have been dropped.

These options were intended to simulate a mobile device being rotated by the user, and had three effects:

• the display output was rotated by 90, 180 or 270 degrees

• the mouse/trackpad input was rotated the opposite way

• the machine model would signal to the guest about its orientation

Of these three things, the input-rotation was coded without being restricted to boards which supported the full set of device-rotation handling, so in theory the options were usable on other machine models to produce an odd effect (rotating input but not display output). But this was never intended or documented behaviour, so we have dropped the options along with the machine models they were intended for.

User-mode emulator command line arguments

-singlestep (removed in 9.0)

The -singlestep option has been given a name that better reflects what it actually does. For both linux-user and bsd-user, use the -one-insn-per-tb option instead.

QEMU Machine Protocol (QMP) commands

block-dirty-bitmap-add “autoload” parameter (removed in 4.2)

The “autoload” parameter has been ignored since 2.12.0. All bitmaps are automatically loaded from qcow2 images.

cpu-add (removed in 5.2)

Use device_add for hotplugging vCPUs instead of cpu-add. See documentation of query-hotpluggable-cpus for additional details.

change (removed in 6.0)

Use blockdev-change-medium or change-vnc-password or display-update instead.

query-events (removed in 6.0)

The query-events command has been superseded by the more powerful and accurate query-qmp-schema command.

migrate_set_cache_size and query-migrate-cache-size (removed in 6.0)

Use migrate_set_parameter and info migrate_parameters instead.

migrate_set_downtime and migrate_set_speed (removed in 6.0)

Use migrate_set_parameter instead.

query-cpus (removed in 6.0)

The query-cpus command is replaced by the query-cpus-fast command.

query-cpus-fast arch output member (removed in 6.0)

The arch output member of the query-cpus-fast command is replaced by the target output member.

chardev client socket with wait option (removed in 6.0)

Character devices creating sockets in client mode should not specify the ‘wait’ field, which is only applicable to sockets in server mode

query-named-block-nodes result encryption_key_missing (removed in 6.0)

Removed with no replacement.

query-block result inserted.encryption_key_missing (removed in 6.0)

Removed with no replacement.

query-named-block-nodes and query-block result dirty-bitmaps[i].status (removed in 6.0)

The status field of the BlockDirtyInfo structure, returned by these commands is removed. Two new boolean fields, recording and busy effectively replace it.

query-block result field dirty-bitmaps (removed in 6.0)

The dirty-bitmaps field of the BlockInfo structure, returned by the query-block command is itself now removed. 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.

object-add option props (removed in 6.0)

Specify the properties for the object as top-level arguments instead.

query-sgx return value member section-size (removed in 8.0)

Member section-size in the return value of query-sgx was superseded by sections.

query-sgx-capabilities return value member section-size (removed in 8.0)

Member section-size in the return value of query-sgx-capabilities was superseded by sections.

query-migrate return value member skipped (removed in 9.1)

Member skipped of the MigrationStats struct hasn’t been used for more than 10 years. Removed with no replacement.

migrate command option inc (removed in 9.1)

Use blockdev-mirror with NBD instead. See “QMP invocation for live storage migration with blockdev-mirror + NBD” in docs/interop/live-block-operations.rst for a detailed explanation.

migrate command option blk (removed in 9.1)

Use blockdev-mirror with NBD instead. See “QMP invocation for live storage migration with blockdev-mirror + NBD” in docs/interop/live-block-operations.rst for a detailed explanation.

migrate-set-capabilities block option (removed in 9.1)

Block migration has been removed. For a replacement, see “QMP invocation for live storage migration with blockdev-mirror + NBD” in docs/interop/live-block-operations.rst.

migrate-set-parameter compress-level option (removed in 9.1)

Use multifd-zlib-level or multifd-zstd-level instead.

migrate-set-parameter compress-threads option (removed in 9.1)

Use multifd-channels instead.

migrate-set-parameter compress-wait-thread option (removed in 9.1)

Removed with no replacement.

migrate-set-parameter decompress-threads option (removed in 9.1)

Use multifd-channels instead.

migrate-set-capability compress option (removed in 9.1)

Use multifd-compression instead.

QEMU Machine Protocol (QMP) events

MEM_UNPLUG_ERROR (removed in 9.1)

MEM_UNPLUG_ERROR has been replaced by the more generic DEVICE_UNPLUG_GUEST_ERROR event.

vcpu trace events (removed in 9.1)

The ability to instrument QEMU helper functions with vCPU-aware trace points was removed in 7.0.

Human Monitor Protocol (HMP) commands

usb_add and usb_remove (removed in 2.12)

Replaced by device_add and device_del (use device_add help for a list of available devices).

host_net_add and host_net_remove (removed in 2.12)

Replaced by netdev_add and netdev_del.

The hub_id parameter of hostfwd_add / hostfwd_remove (removed in 5.0)

The [hub_id name] parameter tuple of the ‘hostfwd_add’ and ‘hostfwd_remove’ HMP commands has been replaced by netdev_id.

cpu-add (removed in 5.2)

Use device_add for hotplugging vCPUs instead of cpu-add. See documentation of query-hotpluggable-cpus for additional details.

change vnc TARGET (removed in 6.0)

No replacement. The change vnc password and change DEVICE MEDIUM commands are not affected.

acl_show, acl_reset, acl_policy, acl_add, acl_remove (removed in 6.0)

The acl_show, acl_reset, acl_policy, acl_add, and acl_remove commands were removed with no replacement. Authorization for VNC should be performed using the pluggable QAuthZ objects.

migrate-set-cache-size and info migrate-cache-size (removed in 6.0)

Use migrate-set-parameters and info migrate-parameters instead.

migrate_set_downtime and migrate_set_speed (removed in 6.0)

Use migrate-set-parameters instead.

info cpustats (removed in 6.1)

This command didn’t produce any output already. Removed with no replacement.

singlestep (removed in 9.0)

The singlestep command has been replaced by the one-insn-per-tb command, which has the same behaviour but a less misleading name.

migrate command -i option (removed in 9.1)

Use blockdev-mirror with NBD instead. See “QMP invocation for live storage migration with blockdev-mirror + NBD” in docs/interop/live-block-operations.rst for a detailed explanation.

migrate command -b option (removed in 9.1)

Use blockdev-mirror with NBD instead. See “QMP invocation for live storage migration with blockdev-mirror + NBD” in docs/interop/live-block-operations.rst for a detailed explanation.

migrate_set_capability block option (removed in 9.1)

Block migration has been removed. For a replacement, see “QMP invocation for live storage migration with blockdev-mirror + NBD” in docs/interop/live-block-operations.rst.

migrate_set_parameter compress-level option (removed in 9.1)

Use multifd-zlib-level or multifd-zstd-level instead.

migrate_set_parameter compress-threads option (removed in 9.1)

Use multifd-channels instead.

migrate_set_parameter compress-wait-thread option (removed in 9.1)

Removed with no replacement.

migrate_set_parameter decompress-threads option (removed in 9.1)

Use multifd-channels instead.

migrate_set_capability compress option (removed in 9.1)

Use multifd-compression instead.

Host Architectures

System emulation on 32-bit Windows hosts (removed in 9.0)

Windows 11 has no support for 32-bit host installs, and Windows 10 did not support new 32-bit installs, only upgrades. 32-bit Windows support has now been dropped by the MSYS2 project. QEMU also is deprecating and dropping support for 32-bit x86 host deployments in general. 32-bit Windows is therefore no longer a supported host for QEMU. Since all recent x86 hardware from the past >10 years is capable of the 64-bit x86 extensions, a corresponding 64-bit OS should be used instead.

Guest Emulator ISAs

RISC-V ISA privilege specification version 1.09.1 (removed in 5.1)

The RISC-V ISA privilege specification version 1.09.1 has been removed. 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

KVM guest support on 32-bit Arm hosts (removed in 5.2)

The Linux kernel has dropped support for allowing 32-bit Arm systems to host KVM guests as of the 5.7 kernel, and was thus removed from QEMU as well. Running 32-bit guests on a 64-bit Arm host remains supported.

RISC-V ISA Specific CPUs (removed in 5.1)

The RISC-V cpus with the ISA version in the CPU name have been removed. 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 no MMU CPUs (removed in 5.1)

The RISC-V no MMU cpus have been removed. The two CPUs: rv32imacu-nommu and rv64imacu-nommu can no longer be used. Instead the MMU status can be specified via the CPU mmu option when using the rv32 or rv64 CPUs.

RISC-V ‘any’ CPU type -cpu any (removed in 9.2)

The ‘any’ CPU type was introduced back in 2018 and was around since the initial RISC-V QEMU port. Its usage was always been unclear: users don’t know what to expect from a CPU called ‘any’, and in fact the CPU does not do anything special that isn’t already done by the default CPUs rv32/rv64.

compat property of server class POWER CPUs (removed in 6.0)

The max-cpu-compat property of the pseries machine type should be used instead.

moxie CPU (removed in 6.1)

Nobody was using this CPU emulation in QEMU, and there were no test images available to make sure that the code is still working, so it has been removed without replacement.

lm32 CPUs (removed in 6.1)

The only public user of this architecture was the milkymist project, which has been dead for years; there was never an upstream Linux port. Removed without replacement.

unicore32 CPUs (removed in 6.1)

Support for this CPU was removed from the upstream Linux kernel, and there is no available upstream toolchain to build binaries for it. Removed without replacement.

x86 Icelake-Client CPU (removed in 7.1)

There isn’t ever Icelake Client CPU, it is some wrong and imaginary one. Use Icelake-Server instead.

Nios II CPU (removed in 9.1)

QEMU Nios II architecture was orphan; Intel has EOL’ed the Nios II processor IP (see Intel discontinuance notification).

CRIS CPU architecture (removed in 9.2)

The CRIS architecture was pulled from Linux in 4.17 and the compiler was no longer packaged in any distro making it harder to run the check-tcg tests.

System accelerators

Userspace local APIC with KVM (x86, removed in 8.0)

-M kernel-irqchip=off cannot be used on KVM if the CPU model includes a local APIC. The split setting is supported, as is using -M kernel-irqchip=off when the CPU does not have a local APIC.

HAXM (-accel hax) (removed in 8.2)

The HAXM project has been retired (see https://github.com/intel/haxm#status). Use “whpx” (on Windows) or “hvf” (on macOS) instead.

MIPS “Trap-and-Emulate” KVM support (removed in 8.0)

The MIPS “Trap-and-Emulate” KVM host and guest support was removed from Linux in 2021, and is not supported anymore by QEMU either.

System emulator machines

s390-virtio (removed in 2.6)

Use the s390-ccw-virtio machine instead.

The m68k dummy machine (removed in 2.9)

Use the none machine with the loader device instead.

xlnx-ep108 (removed in 3.0)

The EP108 was an early access development board that is no longer used. Use the xlnx-zcu102 machine instead.

spike_v1.9.1 and spike_v1.10 (removed in 5.1)

The version specific Spike machines have been removed 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=v1.10.0 command line argument.

mips r4k platform (removed in 5.2)

This machine type was very old and unmaintained. Users should use the malta machine type instead.

mips fulong2e machine alias (removed in 6.0)

This machine has been renamed fuloong2e.

pc-0.10 up to pc-i440fx-2.3 (removed in 4.0 up to 9.0)

These machine types were very old and likely could not be used for live migration from old QEMU versions anymore. Use a newer machine type instead.

Raspberry Pi raspi2 and raspi3 machines (removed in 6.2)

The Raspberry Pi machines come in various models (A, A+, B, B+). To be able to distinguish which model QEMU is implementing, the raspi2 and raspi3 machines have been renamed raspi2b and raspi3b.

Aspeed swift-bmc machine (removed in 7.0)

This machine was removed because it was unused. Alternative AST2500 based OpenPOWER machines are witherspoon-bmc and romulus-bmc.

ppc taihu machine (removed in 7.2)

This machine was removed because it was partially emulated and 405 machines are very similar. Use the ref405ep machine instead.

Nios II 10m50-ghrd and nios2-generic-nommu machines (removed in 9.1)

The Nios II architecture was orphan.

shix (removed in 9.2)

The machine was unmaintained.

Arm machines akita, borzoi, cheetah, connex, mainstone, n800, n810, spitz, terrier, tosa, verdex, z2 (removed in 9.2)

QEMU included models of some machine types where the QEMU code that emulates their SoCs was very old and unmaintained. This code was blocking our ability to move forward with various changes across the codebase, and over many years nobody has been interested in trying to modernise it. We don’t expect any of these machines to have a large number of users, because they’re all modelling hardware that has now passed away into history. We are therefore dropping support for all machine types using the PXA2xx and OMAP2 SoCs. We are also dropping the cheetah OMAP1 board, because we don’t have any test images for it and don’t know of anybody who does.

linux-user mode CPUs

tilegx CPUs (removed in 6.0)

The tilegx guest CPU support has been removed without replacement. It was only implemented in linux-user mode, but support for this CPU was removed from the upstream Linux kernel in 2018, and it has also been dropped from glibc, so there is no new Linux development taking place with this architecture. For running the old binaries, you can use older versions of QEMU.

ppc64abi32 CPUs (removed in 7.0)

The ppc64abi32 architecture has a number of issues which regularly tripped up the CI testing and was suspected to be quite broken. For that reason the maintainers strongly suspected no one actually used it.

nios2 CPU (removed in 9.1)

QEMU Nios II architecture was orphan; Intel has EOL’ed the Nios II processor IP (see Intel discontinuance notification).

TCG introspection features

TCG trace-events (since 6.2)

The ability to add new TCG trace points had bit rotted and as the feature can be replicated with TCG plugins it was removed. If any user is currently using this feature and needs help with converting to using TCG plugins they should contact the qemu-devel mailing list.

System emulator devices

spapr-pci-vfio-host-bridge (removed in 2.12)

The spapr-pci-vfio-host-bridge device type has been replaced by the spapr-pci-host-bridge device type.

ivshmem (removed in 4.0)

Replaced by either the ivshmem-plain or ivshmem-doorbell.

ide-drive (removed in 6.0)

The ‘ide-drive’ device has been removed. Users should use ‘ide-hd’ or ‘ide-cd’ as appropriate to get an IDE hard disk or CD-ROM as needed.

scsi-disk (removed in 6.0)

The ‘scsi-disk’ device has been removed. Users should use ‘scsi-hd’ or ‘scsi-cd’ as appropriate to get a SCSI hard disk or CD-ROM as needed.

sga (removed in 8.0)

The sga device loaded an option ROM for x86 targets which enabled 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 was obsolete. The native SeaBIOS support can be activated by using -machine graphics=off.

pvrdma and the RDMA subsystem (removed in 9.1)

The ‘pvrdma’ device and the whole RDMA subsystem have been removed.

Related binaries

qemu-nbd --partition (removed in 5.0)

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

qemu-img convert -n -o (removed in 5.1)

All options specified in -o are image creation options, so they are now rejected when used with -n to skip image creation.

qemu-img create -b bad file $size (removed in 5.1)

When creating an image with a backing file that could not be opened, qemu-img create used to issue a warning about the failure but proceed with the image creation if an explicit size was provided. However, as the -u option exists for this purpose, it is safer to enforce that any failure to open the backing image (including if the backing file is missing or an incorrect format was specified) is an error when -u is not used.

qemu-img amend to adjust backing file (removed in 6.1)

The use of qemu-img amend to modify the name or format of a qcow2 backing image was never fully documented or tested, and interferes with other amend operations that need access to the original backing image (such as deciding whether a v3 zero cluster may be left unallocated when converting to a v2 image). Any changes to the backing chain should be performed with qemu-img rebase -u either before or after the remaining changes being performed by amend, as appropriate.

qemu-img backing file without format (removed in 6.1)

The use of qemu-img create, qemu-img rebase, or qemu-img convert to create or modify an image that depends on a backing file now requires that an explicit backing format be provided. This is for safety: if QEMU probes a different format than what you thought, the data presented to the guest will be corrupt; similarly, presenting a raw image to a guest allows a potential security exploit if a future probe sees a non-raw image based on guest writes.

To avoid creating unsafe backing chains, you must pass -o backing_fmt= (or the shorthand -F during create) to specify the intended backing format. You may use qemu-img rebase -u to retroactively add a backing format to an existing image. However, be aware that there are already potential security risks to blindly using qemu-img info to probe the format of an untrusted backing image, when deciding what format to add into an existing image.

Block devices

VXHS backend (removed in 5.1)

The VXHS code did not compile since v2.12.0. It was removed in 5.1.

sheepdog driver (removed in 6.0)

The corresponding upstream server project is no longer maintained. Users are recommended to switch to an alternative distributed block device driver such as RBD.

Tools

virtiofsd (removed in 8.0)

There is a newer Rust implementation of virtiofsd at https://gitlab.com/virtio-fs/virtiofsd; this has been stable for some time and is now widely used. The command line and feature set is very close to the removed C implementation.

QEMU guest agent

--blacklist command line option (removed in 9.1)

--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 (removed in 9.1)

The blacklist config file option has been renamed to block-rpcs (to be in sync with the renaming of the corresponding command line option).