QEMU 7.1 implements improvements with memory transfer in Linux
The release of QEMU version 7.1 was announced, featuring a series of improvements for various emulators , most notably changes for ARM and RISC-V, as well as an improvement to memory transfer for Linux. In preparation for version 7.1, over 2800 changes were made by 238 developers.
For those who are new to QEMU, you should know that it allows you to run a program built for one hardware platform on a system with a 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 7.1
In this new version presented for Linux, the zero-copy-send option is implemented , which allows the organization of memory page transfers during live migration without intermediate buffering.
In addition, QMP (QEMU Machine Protocol) adds the ability to use the `block-export-add` command to export NBD images with page data in a "dirty" state. New `query-stats` and `query-stats-schema` commands have also been added for querying statistics from various QEMU subsystems.
Another notable change in this new version of QEMU is that the guest agent has improved compatibility with the Solaris platform and added new commands, 'guest-get-diskstats' and 'guest-get-cpustats', to display disk and CPU status. NVMe SMART information has been added to the 'guest-get-disks' command, and NVMe bus type information has been added to the 'guest-get-fsinfo' command.
In addition, a new LoongArch emulator has been added to support the 64-bit version of the LoongArch instruction set architecture (LA64). The emulator supports Loongson 3 5000 processors and Loongson 7A1000 northbridges.
Furthermore, it is also highlighted that the ARM emulator has implemented new types of emulated machines: Aspeed AST1030 SoC, Qualcomm and AST2600/AST1030 (fby35), in addition to adding support for the emulation of Cortex-A76 and Neoverse-N1 CPUs, as well as SME (Scalable Matrix Extensions), RAS (Reliability, Availability, Serviceability) processor extensions and commands to block internal cache leaks during the execution of speculative instructions in the CPU.
While the RISC-V architecture emulator has added support for the new Instruction Set Extensions (ISAs) defined in specification 1.12.0, as well as additional support for the Sdtrig extension and improved support for vector instructions.
Other notable changes in this new version include:
- Improved debugging options.
- Added Trusted Platform Module (TPM) support to the 'virt' emulated machine and added Ibex SPI support to the 'OpenTitan' machine.
- The x86 emulator for KVM has added support for the virtualization of the LBR (Last Branch Record) trace mechanism.
- Implemented GICv4 interrupt handler emulation for 'virt' machines.
- The HPPA architecture emulator offers a new firmware based on SeaBIOS v6 that supports the use of a PS/2 keyboard in the boot menu.
- Improved serial port emulation.
- Added additional STI console fonts.
- The MIPS architecture emulator for Nios2 boards (-machine 10m50-ghrd) implements vector interrupt controller emulation and shadow register set.
- Improved exception handling.
- Added the ability to use up to 4 16550A UART devices in the OpenRISC architecture emulator for the 'or1k-sim' machine.
- The 390x architecture emulator provides support for Vector-Enhancements Facility 2 (VEF 2) extensions. The s390-ccw BIOS has the ability to boot from disks with a sector size other than 512 bytes.
- Added support for lx106 kernels and cache testing object codes to the Xtensa architecture emulator.
Finally, if you're interested in learning more about the changes and new features in this new version of QEMU 7.1, you can find details and more at the following link.