ChangeLog/6.2

System emulation

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.

Arm

• On macOS hosts with Apple Silicon CPUs we now support the 'hvf' accelerator for running AArch64 guests
• M-profile CPUs now emulate trapping on division by zero via CCR.DIV_0_TRP
• The pl011 UART model now supports sending 'break'
• The Fujitsu A64FX processor model is now supported in TCG ('-cpu a64fx')
• The M-profile MVE extension is now supported, and enabled in the Cortex-M55
• The deprecated machine names 'raspi2' and 'raspi3' have been removed; use 'raspi2b' and 'raspi3b' instead
• The 'virt' machine now supports an emulated ITS
• New machine type: kudo-bmc

PowerPC

• Improved POWER10 support for the 'powernv' machine
• Initial support for POWER10 DD2.0 CPU added
• Added support for FORM2 PAPR NUMA descriptions in the "pseries" machine type
  • With a guest kernel that also has support, this allows for asymmetric and other complex NUMA tolopogies which previously couldn't be communicated to the guest

RISC-V

• Fixup virt flash node
• Don't override users supplied ISA version
• Fixup some CSR accesses
• Fix an overflow in the SiFive CLINT (https://gitlab.com/qemu-project/qemu/-/issues/493)
• ePMP CSR address updates
• SiFive PWM support
• Support for RISC-V ACLINT
• mstatus.SD bug fix for hypervisor extensions
• OpenTitan fix for USB dev address

s390x

• Improved storage key emulation (e.g. fixed address handling, lazy storage key enablement for TCG, ...)
• New gen16 CPU features are now enabled automatically in the latest machine type

SPARC

• Fix for booting sun4m machines with more than 1 CPU

x86

• New Snowridge-v4 CPU model, with split-lock-detect feature disabled

Device emulation and assignment

9pfs

• Fixed an occasional crash when handling 'Twalk' requests; thus bug was introduced in QEMU 6.1.0.

Character devices

• ESCC reset fixes

Block device backends and tools

• qemu-nbd now defaults to writeback caching, rather than writethrough, to match the defaults of qemu-img. While this has better performance, it may affect correctness if you were previously relying on writethrough semantics without explicit use of the '--cache=' option.

TCG

• plugins now have a bool arg parsing helper and cleaned up argument syntax
• the cache plugin is now multi-core aware

Known issues

• see Planning/6.2