Log Message:
Changes 2.0.0:
Incompatible changes
All onboard buses now have distinct names, so that all of them can be reached \ 
with "-device bus=...". As a result of this, some buses that used to \ 
have duplicates got renamed:
i2c-bus.0 to i2c-bus.1 for machines n800, n810;
virtio-mmio-bus.0 to virtio-mmio-bus.3 for vexpress-a15, vexpress-a9;
virtio-mmio-bus.0 to virtio-mmio-bus.31 for virt;
usb-bus.0 to usb-bus.1 for xilinx-zynq-a9, fulong2e;
ide.0 to ide.1 for isapc, mips, g3beige, mac99, prep;
This change requires care when doing migration from 1.x to 2.x QEMU; you need to \ 
specify bus=NEW explicitly on the destination for devices on the renamed bus.
Another bus rename is pci to pci.0 for pseries. This does not require as much \ 
care on migration; if you were specifying "bus=pci" explicitly, QEMU \ 
will not start unless you change that to "bus=pci.0".
qemu-system-arm no longer defaults to the obsolete "integratorcp" if \ 
no machine is specified on the command line (this was a recurring source of \ 
confusion). Users with existing integratorcp images will need to add "-M \ 
integratorcp" to the command line if it is not already present.
Future incompatible changes
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".
Starting with QEMU 2.1, -readconfig will standardize on the name fo the command \ 
line option.
ARM
Support for "-M virt", a board type that only uses virtio devices
Support for "-cpu host" when running under KVM
Support for new 32-bit mode ARMv8 instructions in TCG
Support for all 64-bit mode ARMV8 user-accessible instructions except for the \ 
optional CRC and crypto extensions
Support for AArch64 disassembling (requires a C++ compiler to be installed on \ 
the host)
Initial support for KVM on AArch64 systems (some features such as migration are \ 
not yet implemented)
Support for the Canon PowerShot A1100 DIGIC board using "-M canon-a1100"
Support for the allwinner-a10-based board "-M cubieboard"
Support for flow control in the Cadence UART
"integratorcp" is no longer the default machine (see the 'incompatible \ 
changes' section above)
Power
Support for Altivec 2.07 and VSX instructions when running under TCG
Support for ISA 2.06 "load/store quadword instructions", "divide \ 
extended instructions" and "floating-point test instructions" \ 
when running under TCG
PReP is not anymore (incorrectly) included in qemu-system-ppcemb
Improved support for "-nodefaults" on the pSeries machine. Display \ 
devices created with "-device VGA" will be handled correctly in the \ 
device tree.
Support for boot order in pSeries emulation
s390
Support for adapter interrupts in virtio-cc2
SPARC
Support for Sun CG3 framebuffer with the Sun4m machine. The CG3 framebuffer can \ 
be requested with "-vga cg3".
Support for the CASA compare-and-swap instruction in TCG.
x86
On the Q35 machine, the HPET interrupt can now be attached to GSIs 16-23, like \ 
on real hardware.
The Q35 machine now supports CPU hotplug.
Two flash chips can be specified using the "-drive if=pflash" or \ 
"-pflash" options twice.
Memory layout has changed slightly; to improve performance, the PIIX4 machine \ 
("-M pc") now has 3GB of low memory instead of 3.5GB if the guest has \ 
more than 3.5GB of memory. Similarly, the Q35 machine ("-M q35") now \ 
has 2GB instead of 2.75GB of low memory if the guest has more than 2.75GB of \ 
overall memory.
Support for migration of Intel MPX registers.
The Apple SMC device is now exposed in the ACPI tables.
On the PIIX machine, PCI hotplug now supports devices behind a bridge (only for \ 
bridges not added by hotplug; hot-plugged bridges can still use the PCI Standard \ 
Hot-Plug Controller).
Support for the Hyper-V reference time counter via the "hv-time" \ 
suboption of "-cpu". This can improve performance of Windows guests \ 
substantially for applications that do many floating-point or SIMD operations. \ 
(Requires KVM and Linux 3.14).
The distributed qemupciserial.inf file now allows installing multiport PCI \ 
serial devices on Windows too.
ACPI tables generated by QEMU can now be used by OVMF firmware. OVMF starting \ 
with SVN r15420 is needed. In particular hotplug, pvpanic device and other ACPI \ 
based features now work for OVMF.
KVM
x2apic is now enabled by default when KVM is in use.
Xen
PCI passthrough of devices with a ROM now works.
Xtensa
added support for ML605 and KC705 FPGA boards.
Cache-related opcodes now correctly check privilege level/memory accessibility.