QEMU is a generic machine emulator and virtualizer. It can emulate other CPU and host architectures, or run native binaries with native performances by executing the guest code directly on the host CPU any only emulate devices. It's thus often used in conjunction with KVM on Linux for system virtualization.
minor feature: The number of allow PCI host bridges for pSeries machine was reduced from 256 to 31 (more can be configured by setting up MMIO windows manually). Removed support for tftp:// in the block layer, since this has been broken forever for files bigger than 256KB. Three options are using different names on the command line and in configuration file. In particular:, The "acpi" configuration file section matches command-line option "acpitable"; The "boot-opts" configuration file section matches command-line option "boot"; The "smp-opts" configuration file section matches command-line option "smp". Behavior of automatic calculation of SMP topology when some SMP topology options for -smp are omitted (sockets, cores, threads) will change in the future. If guest ABI needs to be preserved on upgrades while using the SMP topology options, users should either set set all options explicitly (sockets, cores, threads), or omit all of them. Devices "allwinner-a10", "pc87312", "ssi-sd" will be configured with explicit properties instead of implicitly. This is unlikely to affect users. QMP command blockdev-add is still a work in progress. It doesn't support all block drivers, it lacks a matching blockdev-del, and more. It might change incompatibly. For x86, specifying a CPUID feature with both "+feature/-feature" and "feature=on/off" will cause a warning. The current behavior for this combination ("+feature/-feature" wins over "feature=on/off") will be changed so that "+feature" and "-feature" will be synonyms for "feature=on" and "feature=off" respectively). Improvements to the Aspeed board. Support for HLT semihosting traps in AArch32 mode (both ARM and Thumb). The ACPI tables for the "virt" machine type support ITS. The Cadence GEM device now supports multiple priority queues through the num-priority-queues property. The STM32F2xx board (Netduino 2) now includes ADC and SPI devices. Support for 24KEc CPUs. Support for POWER9 CPUs. Improvements for the new "powernv" platform. PCI host