ChangeLog/0.15

0.15.0

Targets

• New targets added: LatticeMico32 and UniCore32.

ARM

• Many bugs in Neon and other ARMv6 and ARMv7 instructions have been fixed
• Floating point instructions now generally handle NaNs and floating point status flags correctly
• Dummy implementations of cp15 performance counters and cp14 debug registers mean we can boot more recent Linux kernels that probe for these features
• SA-1110/SA-1100 support has been added
• New machine models: ARM Versatile Express (machine "vexpress-a9"), Sharp Zaurus SL-5500 (machine "collie")

MIPS

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SH4

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PPC

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s390x

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SPARC

• Sparc32: Improvements to OpenBIOS make Solaris 8 boot possible.
• Sparc64: fix sdivx and udivx instructions, enabling booting HelenOS up to the command prompt (commit).
• Minor Sparc32 and Sparc64 fixes.

Hosts

ARM

• Support QEMU's host C code being compiled in Thumb mode (as some gccs do by default)

MIPS

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IA64

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KVM

Common

• Countless fixes ported over from qemu-kvm, core is now shared with that tree, i.e. has the same quality
• Pimped up threading model, now fully synchronized with qemu-kvm tree
• Removed dependency on external kernel headers, all supported KVM features are now built into the binary

x86

• Paravirtual kvmclock fixes
• Stable guest TSC across migration
• Support for SMEP CPU feature
• Support for VIA CPU features
• Reworked & fixed MCE support

PPC

• ...

s390x

• ...

Devices

IDE / AHCI

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SCSI

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USB

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virtio

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virtio-serial

• Various fixes for hot-unplug of ports
• Disallow generic ports at id 0: port number 0 is reserved for console ports for backward compatibility; '-device virtserialport,nr=0' is now not allowed.
• Allow re-use of a chardev after a port using it gets unplugged
• Add trace events

PCI/PCI Express

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Sound

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Video

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RTC

• MC146818 (for PCs): Follow host clock resets to the past immediately (instead of freezing the clock)

Balloon

• Fix use-after-free bug that lead to qemu crash when 'balloon 0' was issued in the monitor
• Multiple balloon devices are now forbidden; it doesn't make sense to have more than one device at a time.
• Negative balloon values are now rejected. The previous behaviour was to silently deflate the balloon (negative values were parsed as very high positive values)
• Fix memory leaks on exit or unplug of the virtio-balloon device
• Fix migration after unplugging of the virtio-balloon device. Previously, the destination aborted migration for a missing section.

Block Layer

• Added missing -drive options to the man page
• Expose live snapshot support in QMP using the snapshot-blkdev-sync command (commit)
• Fixed removable media support to not cache the media size. Before this fix, the guest OS would see the old CD-ROM size even after changing the medium. (commit)

qemu-img

• qemu-img convert and rebase now support the -p option which enables progress display (commit)
• qemu-img commit, convert and rebase now support the -t option which allows to specify a cache mode that should be used to open the image (commit)
• The performance of qemu-img convert has been improved (commit)

Block Drivers

qcow2

• Improved the performance of creating/deleting internal snapshots (commit)

qed

• Support for growing images with qemu-img resize (commit)
• Periodically flush and clear need check bit to reduce chance of leaving image files dirty on power failure (commit)
• Fix consistency check on 32-bit hosts (commit)

VMDK

• Support for the monolithicFlat subformat (commit)

Sheepdog

• Can now preallocate images during creation (commit)

RBD

• Use the higher level librbd instead of just librados (commit)

IDE Emulation

• Added support for the TRIM command (commit)
• Instead of the device ide-drive for both hard disks and CD-ROMs we have now separate ide-hd and ide-cd devices (commit)
• Fixed confusion between the Busmaster IDE status register and internal error state, which could lead to crashes (commit)

CDROM Emulation

• Many fixes to comply with ATAPI specification
• GET_EVENT_STATUS_NOTIFICATION: Implement 'media' subcommand that helps report tray open/close, media present/absent states to guests. Newer Linux guests (kernels 2.6.38+) rely on this command to revalidate discs.
• Major code refactoring and cleanup

virtio-blk

• The serial number of the drive is now exposed as a qdev property (commit)

SCSI Disk Emulation

• Instead of the device scsi-disk for both hard disks and CD-ROMs we have now separate scsi-hd and scsi-cd devices (commit)

Networking

User space (slirp)

• Fixed DHCP support in restrict (host-only) mode
• Ping packet forwarding to external hosts via unprivileged ICMP sockets of Linux 3.0

Spice

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QMP / Monitor

• Support for two new QMP commands: inject-nmi (commit) and snapshot-blkdev-sync (commit)
• Fixed some issues with the JSON parser (several commits, first one here)
• Added the guest agent (commit)

Tracing

• Make simpletrace.py a Python module for trace analysis scripts (blog), (commit)
• Make 'simple' backend thread-safe (commit)
• Add tracetool --probe-prefix optional argument to prefix DTrace probe names (commit)

Linux-user

• Added support for ppoll, sched_{g,s}etaffinity, epoll, pselect6, prlimit64 syscalls
• Add s390x and unicore32 linux-user targets
• Fix loading binaries from Linux/sparc64 rootfs (commit)
• Numerous bugfixes

New build dependencies (mandatory and optional)

• glib-2.0 (mandatory)
• libcurl 7.15.4 or better (optional, required for CURL block driver support)
• spice 0.6.0 or better (optional)

Other stuff

• Xen support merged (http://blog.xen.org/index.php/2011/05/13/xen-support-upstreamed-to-qemu/)