QEMU 2.2.1 发布，此版本现已提供下载：qemu-2.2.1.tar.bz2。 更新日志： 未来不兼容改进 三个在命令行和配置文件使用不用名称的选项： 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". 以 QEMU xyz.jkl, -readconfig 会标准版命令行选项名称 ARM Support for loading a device tree even with no -kernel option or when booting ELF images Support for input interrupts in the PL061 GPIO controller TCG can emulate breakpoints and watchpoints. Support for PSCI firmware interface emulating in TCG enables clean shutdown from non-kvm guests MIPS Support for MIPS64 Release 6 emulation. Support for MIPS SIMD Architecture emulation. Fix for incorrectly handled delay slots in MIPS16 and microMIPS. PowerPC Mac OS X 10.2, 10.3 and 10.4 guests run with the mac99 machine type (CD-ROM emulation known broken). Bugfixes and optimization for TCG emulation of PowerPC targets. IBM (pSeries) Support for the "nmi" monitor command, to enter the kernel debugger. Live migration support for NVRAM Freescale (BookE) Breakpoint support on KVM. Support for the e500 platform bus and dynamic instantiation of FreeScale eTSEC devices (-device eTSEC). Support for MPC8XXX gpio controller to enable shutdown with 3.19+ Linux guests s390 Enhance support for boot from DASD to handle more formats. Support for memory hotplug. Support for cpu state handling and migration. Support for booting newer kernels under TCG. Improved SMP startup and cpu online/offline performance especially for large guests SPARC Emulation of TCX hardware acceleration (allows X to run under NetBSD and Solaris) NetBSD and OpenBSD can now run under qemu-system-sparc64 in -nographic mode TriCore New target. x86 Support for IOMMU (VT-d) emulation on the Q35 machine type, enabled with "-machine iommu=on". Support for specifying drives in short form on the command-line (i.e. using -cdrom, -hda, -drive if=ide) on the Q35 machine type. TCG is reported to run QNX. All CPUs now work with "-cpu MODEL,enforce", of course as long as TCG or KVM support the CPU's set of features. Previously, a few CPUs included extraneous CPUID flags that cause "-cpu MODEL,enforce" to fail. KVM More robust live migration of the kvm pv clock Support for AVX512 Xen QEMU can now boot a bzImage or multiboot kernel under Xen, using the command line option -kernel. Xtensa New script for automatic core import from xtensa configuration overlay. Device emulation and assignment The boot order set for hot-plugged devices will take effect during reboot. In addition, the boot order can be dynamically modified via QOM. IDE More accurate emulation of AHCI, especially visible with Windows guests. SCSI Passthrough of vendor-specific commands now works (only with the virtio-scsi HBA). Initial support in virtio-scsi for a threaded backend, which is used in the same way as virtio-blk ("-object iothread,id=id" and "-device virtio-scsi-pci,iothread=id"). Note that the code has known thread-safety problems that can lead to QEMU using freed memory. They should not happen in normal use, they can be triggered easily by malicious guests. This option should only be used if you are interested in making relevant parts of QEMU thread safe. Support for LSI MegaRAID SAS 2108 HBAs (-device megasas-gen2). Note that booting from this device does not work yet. virtio-scsi can now execute Abort Task and Abort Task Set task management functions asynchronously. PCI/PCIe MSIs are now (correctly) disabled until bus master DMA is enabled for the device. Support for ARI forwarding on PCIe root ports. USB Support for hot-plugging XHCI/EHCI/UHCI controllers (in the case of EHCI/UHCI, only if there are no companion controllers). Support for USB 2.0 (high speed) mice and keyboards, complementing the existing support for high speed USB tablets. High speed devices avoid the less efficient UHCI controller, and thus use less CPU on the host. VGA The default vga device on x86 has been switched from cirrus to stdvga, which works better for most guests. However, Windows XP will not suspend to RAM anymore; the change can be undone with "-vga cirrus" and does not affect PC machine types of versions 2.1 and earlier. Character devices Support for automatic reconnection of client sockets (e.g. "-chardev socket,host=localhost,port=12345,nowait,reconnect=5"). GUI Monitor The "info pcmcia" command was removed. PCMCIA hotplug was never implemented, and thus the command could only return static information. Migration Network Samba 4.1 is now supported. Block devices in system emulation The list of functionality now supported in threaded virtio-blk backend is growing: new in 2.2 are resizing of disks, device hot-unplug, the embedded NBD server, and background jobs (backup, stream, mirror, commit). 更多内容请看更新日志。 QEMU是一套由Fabrice Bellard所编写的模拟处理器的自由软件。它与Bochs，PearPC近似，但其具有某些后两者所不具备的特性，如高速度及跨平台的特性。经由kqemu这个开源的加速器，QEMU能模拟至接近真实电脑的速度。QEMU有两种主要运作模倾： User mode模拟模式，亦即是使用者模式。QEMU 能启动那些为不同中央处理器编译的Linux程序。而Wine及 Dosemu是其主要目标。 System mode模拟模式，亦即是系统模式。QEMU能模拟整个电脑系统，包括中央处理器及其他周边设备。它使得为系统源代码进行测试及除错工作变得容易。其亦能用来在一部主机上虚拟数部不同虚拟电脑。 QEMU的主体部份是在LGPL下发布的，而其系统模式模拟与kqemu加速器则是在GPL下发布。使用kqemu可使QEMU能模拟至接近实机速度，但其在虚拟的操作系统是Microsoft Windows 98或以下的情况下是无用的。 优点： 可以模拟 IA-32 (x86)个人电脑，AMD64个人电脑， MIPS R4000, 升阳的 SPARC sun3 与 PowerPC (PReP 及 Power Macintosh)架构 支持其他架构，不论在主机或虚拟系统上(请参看QEMU主页以获取完整的清单) 增加了模拟速度，某些程式甚至可以实时运行 可以在其他平台上运行Linux的程式 可以储存及还原运行状态(如运行中的程式) 可以虚拟网络卡 可模拟多CPU QEMU 2.2.1 发布，开源模拟器下载地址
