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.

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
• New CPU type: cortex-a710
• 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

• Block-TLB (BTLB) support for 32-bit PA-RISC CPUs
• New HP C3700 machine emulation, includes an emulated Astro memory controller and some Elroy PCI bridges
• New SeaBIOS-hppa version 10 to support HP C3000 with Astro & Elroy

MIPS

• The fuloong2e machine supports the new audiodev property.

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

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

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

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

TCG

• Support for SHA instructions.

Device emulation and assignment

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.

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.

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

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

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.

User-mode emulation

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.

Testing and CI

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

Known issues

• See Planning/8.2