ChangeLog/1.7

(As of commit fc8ead74674b7129e8f31c2595c76658e5622197).

System emulation

Device emulation

Audio

• The HDA device emulation now includes a mixer by default. Previously this had to be enabled with the configure argument "--enable-mixemu" when building QEMU.
• Audio honors the QEMU_AUDIO_TIMER_PERIOD environment variable and has less CPU utilization by default than previous versions.

Block devices

• Support for the LSI 53C810 SCSI HBA, which unlike the 895A is supported on some very old Windows NT versions.

Device assignment

• VFIO now supports setting CPU affinity on MSI interrupts.
• VFIO can now reset assigned devices much more reliably using either PCI function-level reset (FLR), power management, or a reset (done by the kernel) of the parent bridge.
• Several improvements to the reliability of using option ROMs for devices that are assigned with VFIO.

USB

• Performance and functionality improvements for USB 3.0.

MicroBlaze

• Can now specify an initrd on the command line.

PowerPC

• PowerPC now supports the dump-guest-memory command.

s390x

• The "nmi" command will trigger a crash dump from kdump, using a RESTART interrupt.
• The SCLP line-mode console ("operating system messages") can be accessed with "-device sclplmconsole".

x86

• ACPI tables can be generatedby QEMU and can be used by firmware directly. This will in the future enable new features without modifications of all firmware components (SeaBIOS, OVMF, CoreBoot)
• Initial support for supporting more than 1TB of RAM (but firmware does not yet support this).
• Xen HVM domains can now resume from suspend-to-RAM (S3) state.

Monitor

• Subcommands (like "info block") can now autocomplete their options.
• Help for a single subcommand can be printed with a monitor command such as "help info block".
• New commands "blockdev-snapshot-internal-sync", "blockdev-snapshot-delete-internal-sync" improve support for internal qcow2 snapshot.
• New command "blockdev-add" provides a QMP interface for block device hotplug.

Block devices

• The sheepdog driver supports automatic reconnect after network errors
• The VMDK driver supports files produced by VMWare ESX.
• The qcow2 driver can detect some cases of corruption, and will prevent writing to a corrupted image.
• The throttling algorithm has been rewritten; the new code is more robust, and supports configuration of separate limits for sustained I/O vs. I/O bursts
• The metadata of a file (where each sector of the guest image is stored in the file on the host) can be dumped in human-readable or JSON format using a new command "qemu-img map".

User-mode emulation

• Support for AArch64 binaries.
• M68K ColdFire emulation supports atomic system calls.

Guest agent

• The "filesystem freeze/thaw" commands are now supported on Windows too, where they will invoke the native Volume Shadow Copy Service (VSS).

Miscellaneous

• For targets that have no embedded disassembler, QEMU will now produce hexadecimal dumps instead of just emitting an error when a disassembly is requested. The enclosed script disas-objdump.pl can be used, together with an external objdump program, to convert the dump to a readable disassembly.

Host support

• TCG now runs on x32 hosts.

Known issues

• On Win32, QEMU must be compiled with --disable-coroutine-pool to work around a suspected compiler bug.
• The GTK terminal windows (monitor, serial console, parallel, ...) are still unusable in TCG mode: they lose characters and can raise deadlocks.