ChangeLog/8.2

System emulation

Removed features and incompatible changes

Consult the 'Removed features' page for details of suggested replacement functionality.

• The HAX accelerator is not supported anymore; the project has been retired. Use "whpx" or "hvf" respectively on Windows and macOS.
• The old machine types pc-i440fx-1.4 to pc-i440fx-1.7 have been removed; use a newer machine type instead
• In addition to -audiodev and -audio, QEMU does not create default audio backends anymore if the -nodefaults option are used on the command line.
• If an audio backend is created with -audiodev, each audio client (a sound card or VNC) that wants to use it has to specify an audiodev= property. Previously, the first audiodev command line option would be used as a fallback. However -audio can now be used to configure one or more default audio backends, in lieu of the (deprecated and now removed) QEMU_AUDIO_* environment variables.
• Running QEMU with KVM requires Linux 4.4 or newer. A future version of QEMU will increase the minimum requirement for Arm hosts to Linux 4.19 (also when running KVM); if this is too restrictive for your use case, please contact us at qemu-devel@nongnu.org.

New deprecated options and features

Consult the "Deprecated Features" chapter of the QEMU System Emulation User's Guide for further details of the deprecations and their suggested replacements.

68k

• The Macintosh Quadra 800 (q800) emulation now can boot:
  • MacOS 7.1 - 8.1, with or without virtual memory enabled
  • A/UX 3.0.1
  • NetBSD 9.3
  • Linux (via EMILE)

Arm

• The following machines support the new audiodev property: integratorcp, musicpal, n800, n810, realview-eb, realview-eb-mpcore, realview-pb-a8, realview-pbx-a9, akita, borzoi, spitz, terrier, versatilepb, versatileab, vexpress-a9, vexpress-a15, xlnx-zcu102 z2
• Xilinx Versal board now models the CFU/CFI
• Xilinx Versal board now models the TRNG device
• New CPU types:
  • cortex-a710
  • neoverse-n2
• New architectural features now emulated:
  • FEAT_PACQARMA3
  • FEAT_EPAC
  • FEAT_Pauth2
  • FEAT_FPAC
  • FEAT_FPACCOMBINE
  • FEAT_TIDCP1
  • FEAT_MOPS
  • FEAT_HBC
  • FEAT_HPMN0
• The SMMUv3 now advertises the SMMUv3.1-XNX feature

HPPA

• New 64-bit PA-RISC 2.0 CPU emulation, enable with "-cpu hppa64" and "-cpu hppa" for 32-bit CPU (default)
• New HP C3700 machine emulation, includes an emulated Astro memory controller and four Elroy PCI bridges
• Start 64-bit machine with "-machine C3700" and 32-bit CPU with "-machine B160L"
• Improved TLB performance
• Block-TLB (BTLB) support for 32-bit PA-RISC CPUs
• New SeaBIOS-hppa version 12 to support HP C3000 with Astro & Elroy

MIPS

• The fuloong2e machine supports the new audiodev property.

Nios2

• signal tests disabled due to bitrot

PowerPC

• The pegasos2 and 40p machines support the new audiodev property.

RISC-V

ISA and Extensions

• Add zmmul isa string
• Add smepmp isa string
• Add RISC-V vector cryptographic instruction set support
• Implement WARL behaviour for mcountinhibit/mcounteren
• Add Zihintntl extension ISA string to DTS
• Fix zfa fleq.d and fltq.d
• Add RISC-V KVM AIA Support
• Fix riscv,pmu DT node path in the virt machine
• Update CSR bits name for svadu extension
• Mark zicond non-experimental
• Align the AIA model to v1.0 ratified spec
• Use env_archcpu for better performance
• Rename ext_icboz to ext_zicboz
• Rename ext_icbom to ext_zicbom
• Rename ext_icsr to ext_zicsr
• Rename ext_ifencei to ext_zifencei
• Add RISC-V Virtual IRQs and IRQ filtering support
• Rename epmp to smepmp and expose the extension
• Support zicntr/zihpm flags and disable support
• Update RISC-V vector crypto to ratified v1.0.0
• Support discontinuous PMU counters

Machines

• Remove 'host' CPU from TCG
• riscv_htif Fixup printing on big endian hosts
• Add support for the max CPU
• Detect user choice in TCG
• Remove RVG warning
• Change default linux-user cpu to 'max'
• Update 'virt' machine core limit
• Add query-cpu-model-expansion API

Fixes and Misc

• Fix page_check_range use in fault-only-first
• Fix upper/lower mtime write calculation
• Make rtc variable names consistent
• Use abi type for linux-user target_ucontext
• Fix satp_mode_finalize() when satp_mode.supported = 0
• Fix non-KVM --enable-debug build
• Add new extensions to hwprobe
• Use accelerated helper for AES64KS1I
• Allocate itrigger timers only once
• Respect mseccfg.RLB for pmpaddrX changes
• Don't read the CSR in riscv_csrrw_do64
• Clear CSR values at reset and sync MPSTATE with host
• Fix the typo of inverted order of pmpaddr13 and pmpaddr14
• Replace GDB exit calls with proper shutdown
• Support KVM_GET_REG_LIST
• Deprecate capital 'Z' CPU properties
• Fix vfwmaccbf16.vf
• Clear pmp/smepmp bits on reset
• Ignore pmp writes when RW=01
• Correct CSR_MSECCFG operations
• Clear the Ibex/OpenTitan SPI interrupts even if disabled
• Set the OpenTitan priv to 1.12.0

s390x

• Emulated VFMIN and VFMAX instructions now correctly raise a specification exceptions when bits 1-3 of M5 are set
• Fixed emulated VSTL instruction with a large length
• Fixed emulated VREP instruction to use a 16-bit immediate
• Fixed the "ignored match" case in the emulated VSTRS instruction
• Enable crypto adapter passthrough (vfio-ap) for protected virtualization guests
• Support s390x CPU topology (books and drawers, STSI 15.1.x instruction, PTF instruction) with KVM

Tricore

• Added TC37x CPU that implements ISA v1.6.2
• Added CRCN, FTOU, FTOHP, and HPTOF instructions
• Fixed RCPW/RRPW_INSERT instructions for width=0
• Fixed RCRR_INSERT using the wrong destination register
• Fixed FTOUZ being only available from ISA v1.3.1 upwards

x86

Xen emulation under KVM

• Support PV console and network devices.
• Bug fixes to support running Xen PV guests under "shim", documented in the "Xen HVM guest support" page.
• Simplify command line for block and network devices.

TCG

• Support for SHA instructions.

Device emulation and assignment

Audio

• Added virtio-sound device which implements capture and playback from inside a guest using the configured audio backend of the host machine. It is documented in the "Device Emulation / virtio sound" page.

Block devices

• Parallels Format Driver
  • Improved 'qemu-img check' facility
    • Recover from broken data_off in the header
    • Drop clusters outside of the image file
    • De-duplicate clusters located on the same offset in the host file
  • Introduced ability to execute check automatically (if disk image is opened in read/write mode) if corruption is detected by open
  • Cluster allocation is now based on the cluster used bitmap (clusters could be allocated in holes inside image file)
  • Minimal DISCARD & WRITE_ZEROES support

Graphics

• New virtio-gpu rutabaga device. It allows various abstractions of GPU and display virtualization, coming from the Android/CrosVM graphical stack Rutabaga doc. This should help Android Emulator use upstream QEMU, and offers alternative solutions (or context types) than virgl.
• ati-vga pixman-less support and fixes
• virtio-gpu blob=true VM can now be migrated

Hyper-V

• New Hyper-V Dynamic Memory protocol device hv-balloon. This driver is like virtio-balloon on steroids for Windows guests: it allows both changing the guest memory allocation via ballooning and inserting pieces of extra RAM into it on demand from a provided memory backend via Windows-native Dynamic Memory protocol.

PCI/PCIe

• Added Astro Memory controller with Elroy PCI host busses for PA-RISC (hppa) machines

UFS

• Support for UFS emulation through the new ufs, ufs-lu devices based on spec version v3.1
• Support for multiple logical units through the ufs-lu  device
• Support for UFS initialisation
• Support for SCSI commands including read/write.
• Support for query request commands
• Typical usage:

-drive file=<file>,if=none,id=<drive_id>
-device ufs,serial=<serial>,id=<bus_name>, nutrs=<N[optional]>,nutmrs=<N[optional]>
-device ufs-lu,drive=<drive_id>,bus=<bus_name>

virtio

• virtio-mem now supports to dynamically consume multiple memslots instead of statically a single big one. The feature can be enabled using "dynamic-memslots=on", which can severely reduce KVM memory slot metadata overhead with large virtio-mem devices that only expose a small amount of memory to the VM. Note that the feature is incompatible with vhost devices that provide less than 509 memslots, like most vhost-user devices.
• Added virtio-sound device. See Audio section/virtio-sound

Xen

• Support PV unplug for AHCI disks with the q35 platform.
• Allow creation of PV console devices from the command line.
• Allow creation of PV network devices, including '-nic xxx,model=xen-net-device' and the default NIC.
• Support '-drive file=FILENAME,if=xen' for creating PV block devices with automatic names.

Audio

• Added virtio-sound device. See Audio section/virtio-sound

GUI

• cocoa: add zoom-to-fit display option
• gtk: various minor fixes

GDBStub

• fixes cases where wrong threads were reported to gdb

TCG Plugins

• fix bug in reporting too many instructions to qemu_plugin_tb_n_insns()
• fix locking on execlog
• windows support

Memory backends

• memory-backend-file now supports the "rom" parameter. "share=off,readonly=off,rom=on" can be used for VM-templating with R/O files: open the file R/O, but create writable RAM instead of Read Only Memory (ROM).
• "VM templating" documentation was added

Migration

• Legacy compression migration is deprecated ("compress" as capability, "compress-level", "compress-threads", "compress-wait-thread", "decompress-threads" as parameters). Suggest to use multifd compression instead.
• Block migration is deprecated. QMP command "migrate" parameters "blk" and "inc" are deprecated. Suggest to use driver-mirror with NBD instead.
• Fixed race conditions for postcopy migration when preempt mode is enabled.
• Postcopy recovery now allows network failure to happen even during RECOVER phase.
• Added migration parameter "avail-switchover-bandwidth" migration parameter, can be used when the user observes extremely slow bandwidth during migration, causing migration to never complete.
• Initial part of migration mode "cpr-reboot" integrated.

Block device backends and tools

• The qemu NBD implementation for both server and client now supports the recent NBD protocol extension of 64-bit extended headers. When both sides of an NBD connection support this extension, commands like write zeroes or block status can operate on 64-bit effect lengths, rather than being capped to transaction sizes smaller than 4G.

Miscellaneous

• Allow dump-guest-memory to output standard kdump format

User-mode emulation

runtime

Since this release, qemu linux-user implements and provides vdso for most popular architectures.

alpha

• Emulated /proc/cpuinfo output in linux-user

arm/arm64/aarch64

• Emulated /proc/cpuinfo output in linux-user

Build Information

• Coding style has been updated to allow loop variables
• It is possible to build a non-relocatable binary of QEMU with the configure option --disable-relocatable. The default remains a relocatable install (that is, all the directories within the install prefix are computed based on the path to the executable).

Build Dependencies

• Building QEMU now requires Python 3.8. As a consequence, building on Debian 10 is not supported anymore (unless a newer version of Python is installed by other means).
• Building QEMU now uses the tomli library if Python is older than version 3.11. However, version 2.0.1 is bundled in case tomli is not installed on the host.
• The libfdt library is no longer bundled with QEMU. However, if QEMU is configured with --enable-download and the library is absent, then it will be downloaded and built together if any emulators need it.
• The Pixman library is no longer strictly required. The VC, VNC, Gtk, Spice, screendump features and a few devices still require it.
• When running make check-avocado, the Avocado testing framework and pycdlib must be present if the build tree was configured with --disable-download. Until 8.1, Avocado was always downloaded from PyPI.

Testing and CI

• ccache has been enabled for CI builds
• container backend is now selected by configure script

Known issues

• See https://gitlab.com/qemu-project/qemu/-/milestones/10