net: add initial support for AF_XDP network backend

[mirror_qemu.git] / qemu-options.hx

diff --git a/qemu-options.hx b/qemu-options.hx
index 6be621c23249f397c470fb1ab33fb2b3f6cbf032..2bcf7e4e979c4b16828d6728c0e8396878f9be19 100644 (file)
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2882,6 +2882,19 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
     "                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"
@@ -2927,6 +2940,9 @@ DEF("nic", HAS_ARG, QEMU_OPTION_nic,
 #ifdef CONFIG_NETMAP
     "netmap|"
 #endif
+#ifdef CONFIG_AF_XDP
+    "af-xdp|"
+#endif
 #ifdef CONFIG_POSIX
     "vhost-user|"
 #endif
@@ -2955,6 +2971,9 @@ DEF("net", HAS_ARG, QEMU_OPTION_net,
 #ifdef CONFIG_NETMAP
     "netmap|"
 #endif
+#ifdef CONFIG_AF_XDP
+    "af-xdp|"
+#endif
 #ifdef CONFIG_VMNET
     "vmnet-host|vmnet-shared|vmnet-bridged|"
 #endif
@@ -2962,7 +2981,7 @@ DEF("net", HAS_ARG, QEMU_OPTION_net,
     "                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
@@ -3376,6 +3395,55 @@ SRST
         # 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