ERST
-HXCOMM Deprecated by -audiodev
-DEF("audio-help", 0, QEMU_OPTION_audio_help,
- "-audio-help show -audiodev equivalent of the currently specified audio settings\n",
- QEMU_ARCH_ALL)
-SRST
-``-audio-help``
- Will show the -audiodev equivalent of the currently specified
- (deprecated) environment variables.
-ERST
-
DEF("audio", HAS_ARG, QEMU_OPTION_audio,
"-audio [driver=]driver,model=value[,prop[=value][,...]]\n"
" specifies the audio backend and device to use;\n"
" VALE port (created on the fly) called 'name' ('nmname' is name of the \n"
" netmap device, defaults to '/dev/netmap')\n"
#endif
+#ifdef CONFIG_AF_XDP
+ "-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off]\n"
+ " [,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]\n"
+ " attach to the existing network interface 'name' with AF_XDP socket\n"
+ " use 'mode=MODE' to specify an XDP program attach mode\n"
+ " use 'force-copy=on|off' to force XDP copy mode even if device supports zero-copy (default: off)\n"
+ " use 'inhibit=on|off' to inhibit loading of a default XDP program (default: off)\n"
+ " with inhibit=on,\n"
+ " use 'sock-fds' to provide file descriptors for already open AF_XDP sockets\n"
+ " added to a socket map in XDP program. One socket per queue.\n"
+ " use 'queues=n' to specify how many queues of a multiqueue interface should be used\n"
+ " use 'start-queue=m' to specify the first queue that should be used\n"
+#endif
#ifdef CONFIG_POSIX
"-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n"
" configure a vhost-user network, backed by a chardev 'dev'\n"
#ifdef CONFIG_NETMAP
"netmap|"
#endif
+#ifdef CONFIG_AF_XDP
+ "af-xdp|"
+#endif
#ifdef CONFIG_POSIX
"vhost-user|"
#endif
#ifdef CONFIG_NETMAP
"netmap|"
#endif
+#ifdef CONFIG_AF_XDP
+ "af-xdp|"
+#endif
#ifdef CONFIG_VMNET
"vmnet-host|vmnet-shared|vmnet-bridged|"
#endif
" old way to initialize a host network interface\n"
" (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL)
SRST
-``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]``
+``-nic [tap|bridge|user|l2tpv3|vde|netmap|af-xdp|vhost-user|socket][,...][,mac=macaddr][,model=mn]``
This option is a shortcut for configuring both the on-board
(default) guest NIC hardware and the host network backend in one go.
The host backend options are the same as with the corresponding
# launch QEMU instance
|qemu_system| linux.img -nic vde,sock=/tmp/myswitch
+``-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off][,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]``
+ Configure AF_XDP backend to connect to a network interface 'name'
+ using AF_XDP socket. A specific program attach mode for a default
+ XDP program can be forced with 'mode', defaults to best-effort,
+ where the likely most performant mode will be in use. Number of queues
+ 'n' should generally match the number or queues in the interface,
+ defaults to 1. Traffic arriving on non-configured device queues will
+ not be delivered to the network backend.
+
+ .. parsed-literal::
+
+ # set number of queues to 4
+ ethtool -L eth0 combined 4
+ # launch QEMU instance
+ |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\
+ -netdev af-xdp,id=n1,ifname=eth0,queues=4
+
+ 'start-queue' option can be specified if a particular range of queues
+ [m, m + n] should be in use. For example, this is may be necessary in
+ order to use certain NICs in native mode. Kernel allows the driver to
+ create a separate set of XDP queues on top of regular ones, and only
+ these queues can be used for AF_XDP sockets. NICs that work this way
+ may also require an additional traffic redirection with ethtool to these
+ special queues.
+
+ .. parsed-literal::
+
+ # set number of queues to 1
+ ethtool -L eth0 combined 1
+ # redirect all the traffic to the second queue (id: 1)
+ # note: drivers may require non-empty key/mask pair.
+ ethtool -N eth0 flow-type ether \\
+ dst 00:00:00:00:00:00 m FF:FF:FF:FF:FF:FE action 1
+ ethtool -N eth0 flow-type ether \\
+ dst 00:00:00:00:00:01 m FF:FF:FF:FF:FF:FE action 1
+ # launch QEMU instance
+ |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\
+ -netdev af-xdp,id=n1,ifname=eth0,queues=1,start-queue=1
+
+ XDP program can also be loaded externally. In this case 'inhibit' option
+ should be set to 'on' and 'sock-fds' provided with file descriptors for
+ already open but not bound XDP sockets already added to a socket map for
+ corresponding queues. One socket per queue.
+
+ .. parsed-literal::
+
+ |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\
+ -netdev af-xdp,id=n1,ifname=eth0,queues=3,inhibit=on,sock-fds=15:16:17
+
``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]``
Establish a vhost-user netdev, backed by a chardev id. The chardev
should be a unix domain socket backed one. The vhost-user uses a
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,offset=offset,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,rom=on|off|auto``
Creates a memory file backend object, which can be used to back
the guest RAM with huge pages.
The ``readonly`` option specifies whether the backing file is opened
read-only or read-write (default).
+ The ``rom`` option specifies whether to create Read Only Memory
+ (ROM) that cannot be modified by the VM. Any write attempts to such
+ ROM will be denied. Most use cases want proper RAM instead of ROM.
+ However, selected use cases, like R/O NVDIMMs, can benefit from
+ ROM. If set to ``on``, create ROM; if set to ``off``, create
+ writable RAM; if set to ``auto`` (default), the value of the
+ ``readonly`` option is used. This option is primarily helpful when
+ we want to have writable RAM in configurations that would
+ traditionally create ROM before the ``rom`` option was introduced:
+ VM templating, where we want to open a file readonly
+ (``readonly=on``) and mark the memory to be private for QEMU
+ (``share=off``). For this use case, we need writable RAM instead
+ of ROM, and want to also set ``rom=off``.
+
``-object memory-backend-ram,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave``
Creates a memory backend object, which can be used to back the
guest RAM. Memory backend objects offer more control than the
projects / mirror_qemu.git / blobdiff