ChangeLog/8.1

System emulation

Removed features and incompatible changes

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

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.

• The "-singlestep" command line option is deprecated, as it was very misleadingly named. Its replacement is "-one-insn-per-tb" (for the user-mode emulator) or "-accel one-insn-per-tb=on" (for the system-mode emulator)

Arm

• KVM VMs on a host which supports MTE (the Memory Tagging Extension) can now use MTE in the guest
• Pointer-authentication information is now reported to the gdbstub (a GDB 13 or later will produce better backtraces when pauth is in use by the guest)
• Orangepi-PC, Cubieboard: Add Allwinner WDT watchdog emulation
• mcimxd7-sabre, mcimx6ul-evk: The second ethernet controller PHY is now usable
• fsl-imx6: The SNVS is now implemented, sufficient for the guest to be able to shut down the machine
• The SMMUv3 model can now emulate stage-2 translations (but only as an alternative to, not together with, stage-1)
• Debugging via the gdbstub is now supported when using the hvf acceleration on macos hosts
• xlnx-versal board now emulates a CANFD controller
• New board model: bpim2u (Banana Pi BPI-M2 Ultra)

• New architectural features now emulated:
  • FEAT_PAN3 (Support for SCTLR_ELx.EPAN)
  • FEAT_LSE2 (Large System Extensions v2)

OpenRISC

• Allow FPCSR special purpose register to be accessed in user mode
• Configure FPU to detecting tininess before rounding to align QEMU with architecture specification

RISC-V

ISA and Extensions

• Support subsets of code size reduction extension
• A large collection of mstatus sum changes and cleanups
• Zero init APLIC internal state
• Implement query-cpu-definitions
• Fix Guest Physical Address Translation
• Make sure an exception is raised if a pte is malformed

Machines

• Add signature dump function for spike to run ACT tests
• Add Ventana's Veyron V1 CPU

Fixes and Misc

• Fix invalid riscv,event-to-mhpmcounters entry
• Fix itrigger when icount is used
• Fix mstatus.MPP related support
• Fix the H extension TVM trap
• Restore the predicate() NULL check behavior

Device emulation and assignment

Input devices

• add "virtio-multitouch-pci", a multitouch-capable input device

TPM

• Added TPM TIS I2C device model

Audio

• new PipeWire audio backend (-audiodev pipewire)

Character devices

• It's now possible to specify the input independently from the output with -chardev file (e.g. -chardev file,id=repro,path=/dev/null,input-path=input.txt)

GUI

• gtk: enable multi-touch events
• sdl: various keyboard grab fixes

Tracing

• The final parts of per-vcpu trace events where removed. Those looking to monitor TCG code should look at https://qemu.readthedocs.io/en/latest/devel/tcg-plugins.html

Miscellaneous

• Command-line parsing of sizes using a fraction of a scale (such as "1.5M") has been improved: it is now possible to write ".5G" as a synonym for "512M", and no longer possible to cause qemu to read out of bounds on garbage input such as "9.999e999".

TCG backends

RISC-V

• Support Zba, Zbb, and Zicond standard extensions.

Build Information

Build Dependencies

• The --meson and --sphinx-build options to configure have been removed. Meson and Sphinx will always be invoked through the Python interpreter specified (optionally) with --python or the $PYTHON environment variable; in order to use a host installation of Meson or Sphinx, the corresponding distribution packages (including metadata) will have to be installed in the site-packages directory of that Python interpreter.
• Either pip+setuptools or ensurepip must now be installed to build QEMU. It is recommended to install distlib as well, but the build process tries to cope with its absence and it shouldn't be necessary.
• A new option --enable-download will direct configure to find some missing Python build dependencies. For now this applies to sphinx (downloaded from PyPI) and libslirp (which is then built as a meson subproject). Only required and explicitly enabled dependencies (e.g. only for --enable-docs in the case of Sphinx) are downloaded.
  • The use of subprojects/wrapdb.json (downloaded by "meson wrap update-db") isn't supported yet.
• Starting with QEMU 8.1, only Python 3.8 and newer will be supported (3.7 might work but it is not included in any of the environments that we run CI with).
• new pipewire audio backend requires libpipewire (currently >= 0.3.60)

Known issues

• see Planning/8.1