ChangeLog/3.1

System emulation

Incompatible changes

• The "qemu-system-ppcemb" target has been removed. "qemu-system-ppc" or "qemu-system-ppc64" should be used instead.
• The "tls", "x509", and "x509verify" options to "-vnc" have been removed. The "tls-creds" option should be used instead to point to a "tls-creds-x509" object created using "-object"
• The -drive options "cyls", "heads", "secs", "trans", "addr" and "serial" have been removed. The corresponding options of the "-device" parameter have to be used instead now.
• The "-balloon" option has been removed since it is replaced by "-device virtio-balloon" now.
• The "-nodefconfig" option has been removed. Use "-no-user-config" instead.
• The "-startdate", "-localtime" and "-rtc-td-hack" options have been removed. Use the corresponding parameters of "-rtc" instead.
• The "-tftp", "-bootp", "-redir" and "-smb" options have been removed. Use the corresponding parameters of "-nic" or "-netdev" instead.

New deprecated options and features

• The '-machine enforce-config-section' parameter is replaced by the '-global migration.send-configuration' option.
• The 'name' parameter of the '-net' option is a synonym for the 'id' parameter, which should now be used instead.
• The 'hub_id name' parameter tuple of the 'hostfwd_add' and 'hostfwd_remove' HMP commands has been replaced by 'netdev_id'.
• The PowerPC target 'prep' machine type should be replaced by the '40p' machine type.
• Parsing of key,value pair filenames for the RBD block device
• Incorrect CPU topologies specified by -smp socket,core,thread options that are describing number of VCPUs not equal to 'maxcpus'

Consult the "Deprecated Features" appendix for the full list of historically deprecated features/options.

Arm

• New microbit machine model (initially the only supported device is the UART; more complete device support is planned for the next release)
• Support for the ARMv6M architecture and the Cortex-M0 CPU
• New virtual Xilinx Versal machine model: "xlnx-versal-virt"
• implement some missing hypervisor trap bits in HCR register
• New CPU model: Cortex-A72
• Implement emulation of ARMv8M hardware stack limit checking
• Support Scalable Vector Extension in system emulation mode
• Implement some devices previously missing from mps2-an505 board
• raspi: Support virtual framebuffer/viewport in display device
• Add model of Freescale i.MX6 UltraLite 14x14 EVK Board
• Support execution from small (<1K) MPU regions for M-profile
• GICv2: implement the virtualization extensions
• Emulation of AArch32 virtualization ("Hyp mode") is now supported and enabled on the Cortex-A7 and Cortex-A15

PowerPC

• prep: Deprecate QEMU PReP machine in favour of the 40p machine
• 40p: switch firmware from Open HackWare to OpenBIOS
• 40p: fix IRQ routing to enable the Linux sandalfoot zImage to boot
• Mac Old World/New World: add support for booting from virtio-blk-pci devices (QEMU/OpenBIOS)

s390

• support for vfio-ap (s390 crypto devices)
  • KVM host kernel needs to be 4.20+
• remove deprecated 's390-squash-mcss' option
• add 'max' cpu model

KVM

• add support for etoken facility
• add support for huge page backing

TCG

• add support for instruction flags and AFP registers

SPARC

• sun4u: add support for boot from virtio-blk-pci block devices (QEMU/OpenBIOS)

x86

• Documented recommendations for choosing CPU models to ensure good performance and security of x86 guests.

Crypto subsystem

• The XTS cipher mode performance has been approximately doubled

Block devices and tools

• The "qemu-img convert" command handling of secrets has been fixed, allowing creation of LUKS encrypted target files.

TCG

• A long-standing limitation on TCG that prevented it from being able to execute from anything other than plain RAM or ROM has been lifted. This means that the error "qemu: fatal: Trying to execute code outside RAM or ROM" will no longer occur. Note that in the vast majority of cases this error was the result of a guest bug or user misconfiguration -- in this situation QEMU will now correctly emulate a guest that has run off into nowhere, so instead you will see "guest has hung, producing no output".

Build Information

Build Dependencies

• Support for the GTK2 display frontend has been removed. GTK3 should be used instead
• The minimum GTK3 version is now 3.14.0
• The minimum GNUTLS version is now 3.1.18
• The minimum libgcrypt version is now 1.5.0
• The minimum nettle version is now 2.7.1

Known issues

• see Planning/3.1