DEF("drive", HAS_ARG, QEMU_OPTION_drive,
"-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
" [,cyls=c,heads=h,secs=s[,trans=t]][,snapshot=on|off]\n"
- " [,cache=writethrough|writeback|none][,format=f][,serial=s]\n"
- " [,addr=A][,id=name][,aio=threads|native][,readonly=on|off]\n"
+ " [,cache=writethrough|writeback|none|unsafe][,format=f]\n"
+ " [,serial=s][,addr=A][,id=name][,aio=threads|native]\n"
+ " [,readonly=on|off]\n"
" use 'file' as a drive image\n", QEMU_ARCH_ALL)
STEXI
@item -drive @var{option}[,@var{option}[,@var{option}[,...]]]
@item snapshot=@var{snapshot}
@var{snapshot} is "on" or "off" and allows to enable snapshot for given drive (see @option{-snapshot}).
@item cache=@var{cache}
-@var{cache} is "none", "writeback", or "writethrough" and controls how the host cache is used to access block data.
+@var{cache} is "none", "writeback", "unsafe", or "writethrough" and controls how the host cache is used to access block data.
@item aio=@var{aio}
@var{aio} is "threads", or "native" and selects between pthread based disk I/O and native Linux AIO.
@item format=@var{format}
Writeback caching will report data writes as completed as soon as the data is
present in the host page cache. This is safe as long as you trust your host.
If your host crashes or loses power, then the guest may experience data
-corruption. When using the @option{-snapshot} option, writeback caching is
-used by default.
+corruption.
The host page cache can be avoided entirely with @option{cache=none}. This will
attempt to do disk IO directly to the guests memory. QEMU may still perform
qcow2. If performance is more important than correctness,
@option{cache=writeback} should be used with qcow2.
+In case you don't care about data integrity over host failures, use
+cache=unsafe. This option tells qemu that it never needs to write any data
+to the disk but can instead keeps things in cache. If anything goes wrong,
+like your host losing power, the disk storage getting disconnected accidently,
+etc. you're image will most probably be rendered unusable. When using
+the @option{-snapshot} option, unsafe caching is always used.
+
Instead of @option{-cdrom} you can use:
@example
qemu -drive file=file,index=2,media=cdrom
" add device (based on driver)\n"
" prop=value,... sets driver properties\n"
" use -device ? to print all possible drivers\n"
- " use -device driver,? to print all possible options\n"
- " use -device driver,option=? to print a help for value\n",
+ " use -device driver,? to print all possible properties\n",
QEMU_ARCH_ALL)
STEXI
-@item -device @var{driver}[,@var{option}[=@var{value}][,...]]
+@item -device @var{driver}[,@var{prop}[=@var{value}][,...]]
@findex -device
-Add device @var{driver}. Depending on the device type,
-@var{option} (with default or given @var{value}) may be useful.
-To get a help on possible @var{driver}s, @var{option}s or @var{value}s, use
-@code{-device ?},
-@code{-device @var{driver},?} or
-@code{-device @var{driver},@var{option}=?}.
+Add device @var{driver}. @var{prop}=@var{value} sets driver
+properties. Valid properties depend on the driver. To get help on
+possible drivers and properties, use @code{-device ?} and
+@code{-device @var{driver},?}.
+ETEXI
+
+DEFHEADING(File system options:)
+
+DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
+ "-fsdev local,id=id,path=path,security_model=[mapped|passthrough]\n",
+ QEMU_ARCH_ALL)
+
+STEXI
+
+The general form of a File system device option is:
+@table @option
+
+@item -fsdev @var{fstype} ,id=@var{id} [,@var{options}]
+@findex -fsdev
+Fstype is one of:
+@option{local},
+The specific Fstype will determine the applicable options.
+
+Options to each backend are described below.
+
+@item -fsdev local ,id=@var{id} ,path=@var{path} ,security_model=@var{security_model}
+
+Create a file-system-"device" for local-filesystem.
+
+@option{local} is only available on Linux.
+
+@option{path} specifies the path to be exported. @option{path} is required.
+
+@option{security_model} specifies the security model to be followed.
+@option{security_model} is required.
+
+@end table
+ETEXI
+
+DEFHEADING(Virtual File system pass-through options:)
+
+DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
+ "-virtfs local,path=path,mount_tag=tag,security_model=[mapped|passthrough]\n",
+ QEMU_ARCH_ALL)
+
+STEXI
+
+The general form of a Virtual File system pass-through option is:
+@table @option
+
+@item -virtfs @var{fstype} [,@var{options}]
+@findex -virtfs
+Fstype is one of:
+@option{local},
+The specific Fstype will determine the applicable options.
+
+Options to each backend are described below.
+
+@item -virtfs local ,path=@var{path} ,mount_tag=@var{mount_tag} ,security_model=@var{security_model}
+
+Create a Virtual file-system-pass through for local-filesystem.
+
+@option{local} is only available on Linux.
+
+@option{path} specifies the path to be exported. @option{path} is required.
+
+@option{security_model} specifies the security model to be followed.
+@option{security_model} is required.
+
+
+@option{mount_tag} specifies the tag with which the exported file is mounted.
+@option{mount_tag} is required.
+
+@end table
ETEXI
+DEFHEADING()
+
DEF("name", HAS_ARG, QEMU_OPTION_name,
"-name string1[,process=string2]\n"
" set the name of the guest\n"
use the VNC server until the ACLs have been loaded. This can be
achieved using the @code{acl} monitor command.
+@item lossy
+
+Enable lossy compression methods (gradient, JPEG, ...). If this
+option is set, VNC client may receive lossy framebuffer updates
+depending on its encoding settings. Enabling this option can save
+a lot of bandwidth at the expense of quality.
+
@end table
ETEXI
DEFHEADING(Character device options:)
DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
- "-chardev null,id=id\n"
+ "-chardev null,id=id[,mux=on|off]\n"
"-chardev socket,id=id[,host=host],port=host[,to=to][,ipv4][,ipv6][,nodelay]\n"
- " [,server][,nowait][,telnet] (tcp)\n"
- "-chardev socket,id=id,path=path[,server][,nowait][,telnet] (unix)\n"
+ " [,server][,nowait][,telnet][,mux=on|off] (tcp)\n"
+ "-chardev socket,id=id,path=path[,server][,nowait][,telnet],[mux=on|off] (unix)\n"
"-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
- " [,localport=localport][,ipv4][,ipv6]\n"
- "-chardev msmouse,id=id\n"
+ " [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n"
+ "-chardev msmouse,id=id[,mux=on|off]\n"
"-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
- "-chardev file,id=id,path=path\n"
- "-chardev pipe,id=id,path=path\n"
+ " [,mux=on|off]\n"
+ "-chardev file,id=id,path=path[,mux=on|off]\n"
+ "-chardev pipe,id=id,path=path[,mux=on|off]\n"
#ifdef _WIN32
- "-chardev console,id=id\n"
- "-chardev serial,id=id,path=path\n"
+ "-chardev console,id=id[,mux=on|off]\n"
+ "-chardev serial,id=id,path=path[,mux=on|off]\n"
#else
- "-chardev pty,id=id\n"
- "-chardev stdio,id=id\n"
+ "-chardev pty,id=id[,mux=on|off]\n"
+ "-chardev stdio,id=id[,mux=on|off][,signal=on|off]\n"
#endif
#ifdef CONFIG_BRLAPI
- "-chardev braille,id=id\n"
+ "-chardev braille,id=id[,mux=on|off]\n"
#endif
#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
|| defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
- "-chardev tty,id=id,path=path\n"
+ "-chardev tty,id=id,path=path[,mux=on|off]\n"
#endif
#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
- "-chardev parport,id=id,path=path\n"
+ "-chardev parport,id=id,path=path[,mux=on|off]\n"
#endif
, QEMU_ARCH_ALL
)
The general form of a character device option is:
@table @option
-@item -chardev @var{backend} ,id=@var{id} [,@var{options}]
+@item -chardev @var{backend} ,id=@var{id} [,mux=on|off] [,@var{options}]
@findex -chardev
Backend is one of:
@option{null},
All devices must have an id, which can be any string up to 127 characters long.
It is used to uniquely identify this device in other command line directives.
+A character device may be used in multiplexing mode by multiple front-ends.
+The key sequence of @key{Control-a} and @key{c} will rotate the input focus
+between attached front-ends. Specify @option{mux=on} to enable this mode.
+
Options to each backend are described below.
@item -chardev null ,id=@var{id}
@option{pty} is not available on Windows hosts.
-@item -chardev stdio ,id=@var{id}
+@item -chardev stdio ,id=@var{id} [,signal=on|off]
Connect to standard input and standard output of the qemu process.
-@option{stdio} does not take any options. @option{stdio} is not available on
-Windows hosts.
+
+@option{signal} controls if signals are enabled on the terminal, that includes
+exiting QEMU with the key sequence @key{Control-c}. This option is enabled by
+default, use @option{signal=off} to disable it.
+
+@option{stdio} is not available on Windows hosts.
@item -chardev braille ,id=@var{id}
projects / qemu.git / blobdiff