ChangeLog/5.0

From QEMU

System emulation

Incompatible changes

  • The bluetooth code has been removed without replacement. It was quite neglected over the years and likely not usable anymore. You can passthrough a dedicated USB bluetooth dongle to guests on most machines instead if you still need bluetooth in your guest.
  • The -virtfs_synth option has been removed. You can use -fsdev synth together with -device virtio-9p-... instead.
  • The pc-0.12, pc-0.13, pc-0.14, pc-0.15 machines have been removed.
  • The "-accel" and "-machine accel=" options are now incompatible with each other.
  • The "-tb-size N" option has been replaced by "-accel tcg,tb-size=N".

New deprecated options and features

Consult the "Deprecated Features" appendix for the full list of historically deprecated features/options.

Alpha

68k

Arm

  • The Cortex-M7 CPU is now supported
  • New board: tacoma-bmc
  • New board: Netduino Plus 2
  • QEMU now correctly implements trapping of more EL1 system register accesses to EL2 (eg HCR_EL2 TID1, TID2 bits, HSTR_EL2)
  • The no-op system registers required for a "trivial Jazelle" implementation have been added
  • The DC CVAP and DC CVADP instructions are now supported
  • Support for blocking semiconsole SYS_READC
  • the i.MX RNGC device is now supported
  • The Cortex-R5 and -R5f CPUs now provide a PMU
  • The Exynos4210 SoC model now correctly handles DMA to/from the UARTs

HPPA

Microblaze

MIPS

  • Support for R4000 machine is announced to be deprecated, and will be removed from code base in QEMU 5.2.

Nios2

OpenRISC

  • Fixed a bug that prevented the DZF bit of the FPCSR being set.

PowerPC

  • pseries machine type
    • No longer require a reconfiguration reboot for a guest selecting XIVE interrupt controller when ic-mode=dual
    • Now consumes less host resources when running a KVM guest with XIVE (with a recent enough host kernel). This allows running more concurrent guests with KVM accelerated XIVE.
  • powernv machine type
    • Numerous improvements to the model
    • Can now run KVM guests under a TCG emulated powernv machine
    • Basic POWER10 support
    • Removed num-chips machine property, use -smp sockets=NN instead

RISC-V

s390

SH

SPARC

TileGX

Tricore

x86

Xtensa

Device emulation and assignment

ACPI

Audio

Block devices

Graphics

Input devices

IPMI

Network devices

NVDIMM

PCI/PCIe

SCSI

SMBIOS

TPM

USB

VFIO

virtio

Xen

fw_cfg

9pfs

Semihosting

Audio

Character devices

Crypto subsystem

GUI

Host support

Memory backends

Monitor

QMP

Migration

  • Add dbus-vmstate, a backend that allows external processes to migrate their data along with QEMU. See the documentation.

Network

Block device backends and tools

Tracing

  • DEBUG_MMAP build hack replaced by target_mmap_* tracepoints

Miscellaneous

  • It is now possible to specify multiple "-accel" options. The first available accelerator will be used. For example, "-machine accel=kvm:tcg" can now be expressed as "-accel kvm -accel tcg" with the added possibility of including options to configure the accelerator.
  • KVM and Xen-specific machine options have been moved to "-accel"; the previous way to set the option is still available for backwards-compatibility. The options that were moved are:
    • "-machine kernel_irqchip=" (now "-accel kvm,kernel-irqchip=")
    • "-machine kvm_shadow_mem=" (now "-accel kvm,kvm-shadow-mem=")
    • "-machine igd-passthru=" (now "-accel xen,igd-passthrough=")
  • changing the logfile via HMP is now atomically thread-safe
  • virtiofsd is now included, this works with the vhost-user-fs device to provide a passthrough to a host filesystem directory.

User-mode emulation

TCG

Guest agent

  • The 'set-guest-time' command is now fenced off on systems that do not have the 'hwclock' command available (e.g. on s390x).

Build Information

Python

GIT submodules

Container Based Builds

  • --disable-containers allows configure to skip attempting to use them from cross builds (useful on non-x86 builds)

Build Dependencies

Testing

  • multiarch targets added to Travis

Windows

Known issues