removed-features.rst

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This option has been replaced by -net user,guestfwd=....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-net dump[,vlan=n][,file=filename][,len=maxlen] has been replaced by -object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=maxlen].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 secret_keyring objects (removed in 7.1)

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 should simply be 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>.

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.