Log Message:
Update to 4.0.0

Changelog:
Incompatible changes

    The "handle" option to -fsdev and -virtfs has been removed. The \ 
"local" or "proxy" options should be used instead.
    The "-virtioconsole" option has been removed. Use "-device \ 
virtconsole" instead.
    The "-no-frame" option has been removed. It was only usable with \ 
SDL1.2, and support for this library has been suspended now.
    The "-enable-hax" option has been removed. Use "-accel \ 
hax" instead.
    The "-clock" option has been removed. It was only a \ 
"dummy" option without meaning since QEMU 1.7, so there is no \ 
replacement.
    The legacy "ivshmem" device has been removed. Use \ 
"ivshmem-doorbell" or "ivshmem-plain" instead.
    The x86 machine types "pc-0.10" and "pc-0.11" have been \ 
removed. Use a newer machine type instead.
    The "irq" property of the "spapr-vscsi", \ 
"spapr-vlan" and "spapr-vty" devices has been removed with \ 
no replacement.
    The "memory-backend-memfd" backend object type will be reported as \ 
unavailable on hosts systems without memfd sealing support. On previous \ 
versions, "memory-backend-memfd" was reported as available, but didn't \ 
work properly without sealing support.
    HMP snapshot commands (such as "savevm", "loadvm" and \ 
"delvm") use only the snapshot tag, and not the ID any more, to \ 
identify snapshots. This removes ambiguity from the interface, but may require \ 
changing the HMP command in existing scripts.

New deprecated options and features

    cpu-add QMP/HMP command
    machine-types pc-0.12, pc-0.13, pc-0.14 and pc-0.15
    qemu-nbd --partition=N option
    The query-events QMP command has been superseded by the more powerful and \ 
accurate query-qmp-schema command.
    The acl option to the "-vnc" argument has been replaced by the \ 
tls-authz and sasl-authz options.
    The acl_show, acl_reset, acl_policy, acl_add, and acl_remove commands are \ 
deprecated with no replacement. Authorization for VNC should be performed using \ 
the pluggable QAuthZ objects.
    QEMU_AUDIO_ environment variables and "-audio-help" are now \ 
deprecated. Use "-audiodev" instead.

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

Architercture specific summary:
Arm

    Implement the ARMv8.0-SB extension
    Implement the ARMv8.0-PredInv extension
    Implement the ARMv8.1-HPD extension
    Implement the ARMv8.1-LOR extension (as the trivial "no limited \ 
ordering regions provided" minimum)
    Implement the ARMv8.2-FHM extension
    Implement the ARMv8.2-AA32HPD extension
    Implement the ARMv8.3-PAuth extension
    Implement the ARMv8.3-JSConv extension
    Implement the ARMv8.4-CondM extension
    Implement the ARMv8.5-CondM extension
    Implement the ARMv8.5-FRINT extension
    And new boards

MIPS

    Added support for I7200 CPU (nanoMIPS32 ISA + DSP ASE; system mode only).
    Added support for I6500 CPU (MIPS64R6 ISA + MSA ASE + multicore features).
    Added support for QMP-based querying of the available CPU types.
    Added support for SAARI and SAAR configuration registers.
    Added support for MTTCG (multi-threaded TCG).
    Improved support for ITU (Interthread Communication Unit).
    Improved support for Fulong 2E machine.
    Improved end user documentation.
    Fixed build for MIPS n32 hosts.

RISC-V

    The virt board now supports PCI and USB.
    The FS field of mstatus now supports three states (dirty, clean, and off).
    The TSR, TW, and TVM fields of mstatus are now implemented.
    The misa CSR is now writable.
    The built-in gdbserver supports register lists via XML files.
    The sifive_u machine supports SMP.
    The SiFive UART supports TX interrupts.
    The sifive_u machine has the correct number of PLIC interrupts.

x86

    The HAX accelerator is now supported for POSIX hosts other than Darwin, \ 
including Linux and NetBSD.
    Machines pc-* now support configuring firmware with -machine \ 
pflash0=ID0,pflash1=ID1 in addition to -drive if=pflash,... This permits use of \ 
-blockdev.
    MPX is considered a failed experiment by Intel, and has thus been removed \ 
from all named CPU models. It is still accessible via "-cpu host".
    PVH Linux images can be booted with "-kernel".