QEMU is a processor emulator based on dynamic binary translation
The release of the new version QEMU 8.0, in which in preparation for version 8.0, made more than 2800 changes from 238 developers and various improvements are implemented for the emulators, as well as greater support, among other things.
For those who are unaware of QEMU, they should know that it isallows you to run a program created for a hardware platform on a system with ato completely different architecture, for example, running an ARM application on an x86-compatible PC.
In virtualization mode in QEMU, the performance of code execution in an isolated environment is similar to that of a hardware system due to the direct execution of instructions on the CPU and the use of the Xen hypervisor or KVM module.
Main novelties of QEMU 8.0
In this new version of QEMU 8.0 that is presented, it stands out thator support for running Xen guests in an environment based on the KVM hypervisor and Linux 5.12+ kernels in the x86 architecture emulator, as well as added support for the FSRM, FZRM, FSRS and FSRC CPUID flags in the classic x86 TCG code generator and implemented the support for the new Intel Sapphire Rapids (Intel 7) CPU model.
In addition to this, it is also highlighted thate Updated implementation for OpenTitan, PolarFire and OpenSBI machines emulated in the RISC-V architecture emulator and added support for additional processor instruction sets (ISA) and extensions: Smstateen, icount debug counters, virtual mode cache related PMU events, ACPI extensions, Zawrs, Svadu, T-Head and Zicond.
The emulator ARM has implemented support for Cortex-A55 and Cortex-R52 CPUs, added a new Olimex STM32 H405 emulated machine type, added support for FEAT_EVT (enhanced virtualization traps), FEAT_FGT (fine-grained traps), and AArch32 ARMv8-R processor extensions _ Added support for system logs in gdbstub for the architecture of profile M (microcontroller profile).
On the other hand, it is mentioned that in this new version of QEMU 8.0 Deprecated and will soon be discontinued la emulation support system (launching the entire operating system, including KVM and Xen hypervisors) on 86-bit x32 hosts, It is mentioned that support for user-mode emulation (running separate processes created for a different CPU) on 86-bit x32 hosts will continue.
We can also find that support for the fid statement has been added (floating point identification) to the HPPA architecture emulator and emulation in 32-bit mode has been improved, as well as handling of forwarded zPCI devices has been improved.
Of the other changes that stand out from this new version of QEMU 8.0:
- The 390x architecture emulator supports asynchronous memory stripping when restarting secure KVM guests.
- The virtio-mem mechanism, which allows you to hot plug and unplug memory from virtual machines, implements preallocation during live migration.
- Experimental support for migration has been updated in VFIO (Virtual Function I/O) (the second edition of the migration protocol is involved).
- The qemu-nbd block device has improved performance over TCP when using TLS.
- Initial support for OpenBSD and NetBSD has been added to the guest agent.
- Fix PMP propagation for tlb
- Remove redundant ipi-id property on virt machine
- Solution to the cause of the mret exception when no pmp rule is configured
- Fixed bug where disabling compressed instructions would crash QEMU
- Device tree cleaning and loading firmwareA collection of fixes for virtualization
- A workaround for the virtual instruction exception
- A fix for PMP matching to prevent misapplication of default permissions on PMP permission violations.
- Fixes for vector slide instructions to avoid truncating 64-bit values (like doubles) into 32-bit targets.
- Fixes to gdbstub, CSR accesses, dependencies between the various floating point exceptions, and XTheadMemPair.
- Fix wrong record name in disassembler for fmv, fabs, fneg instructions
Finally if you are interested in knowing more about it of the changes and novelties that are presented in this new version of QEMU 8.0 you can consult the details and more in the following link.