@item -machine [type=]@var{name}[,prop=@var{value}[,...]]
@findex -machine
Select the emulated machine by @var{name}. Use @code{-machine help} to list
-available machines. Supported machine properties are:
+available machines.
+
+For architectures which aim to support live migration compatibility
+across releases, each release will introduce a new versioned machine
+type. For example, the 2.8.0 release introduced machine types
+``pc-i440fx-2.8'' and ``pc-q35-2.8'' for the x86_64/i686 architectures.
+
+To allow live migration of guests from QEMU version 2.8.0, to QEMU
+version 2.9.0, the 2.9.0 version must support the ``pc-i440fx-2.8''
+and ``pc-q35-2.8'' machines too. To allow users live migrating VMs
+to skip multiple intermediate releases when upgrading, new releases
+of QEMU will support machine types from many previous versions.
+
+Supported machine properties are:
@table @option
@item accel=@var{accels1}[:@var{accels2}[:...]]
This is used to enable an accelerator. Depending on the target architecture,
qemu-system-i386 -global ide-hd.physical_block_size=4096 disk-image.img
@end example
-In particular, you can use this to set driver properties for devices which are
-created automatically by the machine model. To create a device which is not
+In particular, you can use this to set driver properties for devices which are
+created automatically by the machine model. To create a device which is not
created automatically and set properties on it, use -@option{device}.
-global @var{driver}.@var{prop}=@var{value} is shorthand for -global
The path to the image file in the local filesystem
@item aio
Specifies the AIO backend (threads/native, default: threads)
+@item locking
+Specifies whether the image file is protected with Linux OFD / POSIX locks. The
+default is to use the Linux Open File Descriptor API if available, otherwise no
+lock is applied. (auto/on/off, default: auto)
@end table
Example:
@example
"-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
" use path to provide path to a character device; default is /dev/tpm0\n"
" use cancel-path to provide path to TPM's cancel sysfs entry; if\n"
- " not provided it will be searched for in /sys/class/misc/tpm?/device\n",
+ " not provided it will be searched for in /sys/class/misc/tpm?/device\n"
+ "-tpmdev emulator,id=id,chardev=dev\n"
+ " configure the TPM device using chardev backend\n",
QEMU_ARCH_ALL)
STEXI
@item -tpmdev @var{backend} ,id=@var{id} [,@var{options}]
@findex -tpmdev
-Backend type must be:
-@option{passthrough}.
+Backend type must be either one of the following:
+@option{passthrough}, @option{emulator}.
The specific backend type will determine the applicable options.
The @code{-tpmdev} option creates the TPM backend and requires a
Note that the @code{-tpmdev} id is @code{tpm0} and is referenced by
@code{tpmdev=tpm0} in the device option.
+@item -tpmdev emulator, id=@var{id}, chardev=@var{dev}
+
+(Linux-host only) Enable access to a TPM emulator using Unix domain socket based
+chardev backend.
+
+@option{chardev} specifies the unique ID of a character device backend that provides connection to the software TPM server.
+
+To create a TPM emulator backend device with chardev socket backend:
+@example
+
+-chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
+
+@end example
+
@end table
ETEXI
ETEXI
DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
- "-sandbox <arg> Enable seccomp mode 2 system call filter (default 'off').\n",
+ "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \
+ " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \
+ " Enable seccomp mode 2 system call filter (default 'off').\n" \
+ " use 'obsolete' to allow obsolete system calls that are provided\n" \
+ " by the kernel, but typically no longer used by modern\n" \
+ " C library implementations.\n" \
+ " use 'elevateprivileges' to allow or deny QEMU process to elevate\n" \
+ " its privileges by blacklisting all set*uid|gid system calls.\n" \
+ " The value 'children' will deny set*uid|gid system calls for\n" \
+ " main QEMU process but will allow forks and execves to run unprivileged\n" \
+ " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \
+ " blacklisting *fork and execve\n" \
+ " use 'resourcecontrol' to disable process affinity and schedular priority\n",
QEMU_ARCH_ALL)
STEXI
-@item -sandbox @var{arg}
+@item -sandbox @var{arg}[,obsolete=@var{string}][,elevateprivileges=@var{string}][,spawn=@var{string}][,resourcecontrol=@var{string}]
@findex -sandbox
Enable Seccomp mode 2 system call filter. 'on' will enable syscall filtering and 'off' will
disable it. The default is 'off'.
+@table @option
+@item obsolete=@var{string}
+Enable Obsolete system calls
+@item elevateprivileges=@var{string}
+Disable set*uid|gid system calls
+@item spawn=@var{string}
+Disable *fork and execve
+@item resourcecontrol=@var{string}
+Disable process affinity and schedular priority
+@end table
ETEXI
DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
command line and device configuration into file or dash @code{-}) character to print the
output to stdout. This can be later used as input file for @code{-readconfig} option.
ETEXI
-DEF("nodefconfig", 0, QEMU_OPTION_nodefconfig,
- "-nodefconfig\n"
- " do not load default config files at startup\n",
- QEMU_ARCH_ALL)
-STEXI
-@item -nodefconfig
-@findex -nodefconfig
-Normally QEMU loads configuration files from @var{sysconfdir} and @var{datadir} at startup.
-The @code{-nodefconfig} option will prevent QEMU from loading any of those config files.
-ETEXI
+HXCOMM Deprecated, same as -no-user-config
+DEF("nodefconfig", 0, QEMU_OPTION_nodefconfig, "", QEMU_ARCH_ALL)
DEF("no-user-config", 0, QEMU_OPTION_nouserconfig,
"-no-user-config\n"
- " do not load user-provided config files at startup\n",
+ " do not load default user-provided config files at startup\n",
QEMU_ARCH_ALL)
STEXI
@item -no-user-config
@findex -no-user-config
The @code{-no-user-config} option makes QEMU not load any of the user-provided
-config files on @var{sysconfdir}, but won't make it skip the QEMU-provided config
-files from @var{datadir}.
+config files on @var{sysconfdir}.
ETEXI
DEF("trace", HAS_ARG, QEMU_OPTION_trace,
"-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
@table @option
-@item -object memory-backend-file,id=@var{id},size=@var{size},mem-path=@var{dir},share=@var{on|off}
+@item -object memory-backend-file,id=@var{id},size=@var{size},mem-path=@var{dir},share=@var{on|off},discard-data=@var{on|off}
Creates a memory file backend object, which can be used to back
the guest RAM with huge pages. The @option{id} parameter is a
The @option{share} boolean option determines whether the memory
region is marked as private to QEMU, or shared. The latter allows
a co-operating external process to access the QEMU memory region.
+Setting the @option{discard-data} boolean option to @var{on}
+indicates that file contents can be destroyed when QEMU exits,
+to avoid unnecessarily flushing data to the backing file. Note
+that @option{discard-data} is only an optimization, and QEMU
+might not discard file contents if it aborts unexpectedly or is
+terminated using SIGKILL.
@item -object rng-random,id=@var{id},filename=@var{/dev/random}
projects / mirror_qemu.git / blobdiff