issued on other occasions where a cluster gets freed
(on/off; default: off)
+ ``discard-no-unref``
+ When enabled, discards from the guest will not cause cluster
+ allocations to be relinquished. This prevents qcow2 fragmentation
+ that would be caused by such discards. Besides potential
+ performance degradation, such fragmentation can lead to increased
+ allocation of clusters past the end of the image file,
+ resulting in image files whose file length can grow much larger
+ than their guest disk size would suggest.
+ If image file length is of concern (e.g. when storing qcow2
+ images directly on block devices), you should consider enabling
+ this option.
+
``overlap-check``
Which overlap checks to perform for writes to the image
(none/constant/cached/all; default: cached). For details or
QEMU_ARCH_ALL)
SRST
``-qmp dev``
- Like -monitor but opens in 'control' mode.
+ Like ``-monitor`` but opens in 'control' mode. For example, to make
+ QMP available on localhost port 4444::
+
+ -qmp tcp:localhost:4444,server=on,wait=off
+
+ Not all options are configurable via this syntax; for maximum
+ flexibility use the ``-mon`` option and an accompanying ``-chardev``.
+
ERST
DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \
"-qmp-pretty dev like -qmp but uses pretty JSON formatting\n",
QEMU_ARCH_ALL)
SRST
``-qmp-pretty dev``
- Like -qmp but uses pretty JSON formatting.
+ Like ``-qmp`` but uses pretty JSON formatting.
ERST
DEF("mon", HAS_ARG, QEMU_OPTION_mon, \
"-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL)
SRST
``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]``
- Setup monitor on chardev name. ``mode=control`` configures
- a QMP monitor (a JSON RPC-style protocol) and it is not the
- same as HMP, the human monitor that has a "(qemu)" prompt.
- ``pretty`` is only valid when ``mode=control``,
+ Set up a monitor connected to the chardev ``name``.
+ QEMU supports two monitors: the Human Monitor Protocol
+ (HMP; for human interaction), and the QEMU Monitor Protocol
+ (QMP; a JSON RPC-style protocol).
+ The default is HMP; ``mode=control`` selects QMP instead.
+ ``pretty`` is only valid when ``mode=control``,
turning on JSON pretty printing to ease
human reading and debugging.
+
+ For example::
+
+ -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \
+ -mon chardev=mon1,mode=control,pretty=on
+
+ enables the QMP monitor on localhost port 4444 with pretty-printing.
ERST
DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \
DEF("async-teardown", 0, QEMU_OPTION_asyncteardown,
"-async-teardown enable asynchronous teardown\n",
QEMU_ARCH_ALL)
-#endif
SRST
``-async-teardown``
- Enable asynchronous teardown. A new process called "cleanup/<QEMU_PID>"
- will be created at startup sharing the address space with the main qemu
- process, using clone. It will wait for the main qemu process to
- terminate completely, and then exit.
- This allows qemu to terminate very quickly even if the guest was
- huge, leaving the teardown of the address space to the cleanup
- process. Since the cleanup process shares the same cgroups as the
- main qemu process, accounting is performed correctly. This only
- works if the cleanup process is not forcefully killed with SIGKILL
- before the main qemu process has terminated completely.
+ This option is deprecated and should no longer be used. The new option
+ ``-run-with async-teardown=on`` is a replacement.
+ERST
+DEF("run-with", HAS_ARG, QEMU_OPTION_run_with,
+ "-run-with async-teardown[=on|off]\n"
+ " misc QEMU process lifecycle options\n"
+ " async-teardown=on enables asynchronous teardown\n",
+ QEMU_ARCH_ALL)
+SRST
+``-run-with``
+ Set QEMU process lifecycle options.
+
+ ``async-teardown=on`` enables asynchronous teardown. A new process called
+ "cleanup/<QEMU_PID>" will be created at startup sharing the address
+ space with the main QEMU process, using clone. It will wait for the
+ main QEMU process to terminate completely, and then exit. This allows
+ QEMU to terminate very quickly even if the guest was huge, leaving the
+ teardown of the address space to the cleanup process. Since the cleanup
+ process shares the same cgroups as the main QEMU process, accounting is
+ performed correctly. This only works if the cleanup process is not
+ forcefully killed with SIGKILL before the main QEMU process has
+ terminated completely.
ERST
+#endif
DEF("msg", HAS_ARG, QEMU_OPTION_msg,
"-msg [timestamp[=on|off]][,guest-name=[on|off]]\n"
they are specified. Note that the 'id' property must be set. These
objects are placed in the '/objects' path.
- ``-object memory-backend-file,id=id,size=size,mem-path=dir,share=on|off,discard-data=on|off,merge=on|off,dump=on|off,prealloc=on|off,host-nodes=host-nodes,policy=default|preferred|bind|interleave,align=align,readonly=on|off``
+ ``-object memory-backend-file,id=id,size=size,mem-path=dir,share=on|off,discard-data=on|off,merge=on|off,dump=on|off,prealloc=on|off,host-nodes=host-nodes,policy=default|preferred|bind|interleave,align=align,offset=offset,readonly=on|off``
Creates a memory file backend object, which can be used to back
the guest RAM with huge pages.
such cases, users can specify the required alignment via this
option.
+ The ``offset`` option specifies the offset into the target file
+ that the region starts at. You can use this parameter to back
+ multiple regions with a single file.
+
The ``pmem`` option specifies whether the backing file specified
by ``mem-path`` is in host persistent memory that can be
accessed using the SNIA NVM programming model (e.g. Intel
projects / mirror_qemu.git / blobdiff