net: Adding netmap network backend

This patch adds support for a network backend based on netmap.
netmap is a framework for high speed packet I/O. You can use it
to build extremely fast traffic generators, monitors, software
switches or network middleboxes. Its companion software switch
VALE lets you interconnect virtual machines.
netmap and VALE are implemented as a non-intrusive kernel module,
support NICs from multiple vendors, are part of standard FreeBSD
distributions and available in source format for Linux too.

To compile QEMU with netmap support, use the following configure
options:
    ./configure [...] --enable-netmap --extra-cflags=-I/path/to/netmap/sys
where "/path/to/netmap" contains the netmap source code, available at
    http://info.iet.unipi.it/~luigi/netmap/

The same webpage contains more information about the netmap project
(together with papers and presentations).

Signed-off-by: Vincenzo Maffione <v.maffione@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

configure

@@ -169,6 +169,7 @@ curl=""
 curses=""
 docs=""
 fdt=""
+netmap="no"
 pixman=""
 sdl=""
 virtfs=""
@@ -488,6 +489,7 @@ FreeBSD)
   audio_possible_drivers="oss sdl esd pa"
   # needed for kinfo_getvmmap(3) in libutil.h
   LIBS="-lutil $LIBS"
+  netmap=""  # enable netmap autodetect
 ;;
 DragonFly)
   bsd="yes"
@@ -797,6 +799,10 @@ for opt do
   ;;
   --enable-vde) vde="yes"
   ;;
+  --disable-netmap) netmap="no"
+  ;;
+  --enable-netmap) netmap="yes"
+  ;;
   --disable-xen) xen="no"
   ;;
   --enable-xen) xen="yes"
@@ -1182,6 +1188,8 @@ echo "  --disable-uuid           disable uuid support"
 echo "  --enable-uuid            enable uuid support"
 echo "  --disable-vde            disable support for vde network"
 echo "  --enable-vde             enable support for vde network"
+echo "  --disable-netmap         disable support for netmap network"
+echo "  --enable-netmap          enable support for netmap network"
 echo "  --disable-linux-aio      disable Linux AIO support"
 echo "  --enable-linux-aio       enable Linux AIO support"
 echo "  --disable-cap-ng         disable libcap-ng support"
@@ -2094,6 +2102,26 @@ EOF
   fi
 fi
 
+##########################################
+# netmap headers probe
+if test "$netmap" != "no" ; then
+  cat > $TMPC << EOF
+#include <inttypes.h>
+#include <net/if.h>
+#include <net/netmap.h>
+#include <net/netmap_user.h>
+int main(void) { return 0; }
+EOF
+  if compile_prog "" "" ; then
+    netmap=yes
+  else
+    if test "$netmap" = "yes" ; then
+      feature_not_found "netmap"
+    fi
+    netmap=no
+  fi
+fi
+
 ##########################################
 # libcap-ng library probe
 if test "$cap_ng" != "no" ; then
@@ -3751,6 +3779,7 @@ echo "uname -r          $uname_release"
 echo "GUEST_BASE        $guest_base"
 echo "PIE               $pie"
 echo "vde support       $vde"
+echo "netmap support    $netmap"
 echo "Linux AIO support $linux_aio"
 echo "ATTR/XATTR support $attr"
 echo "Install blobs     $blobs"
@@ -3888,6 +3917,9 @@ fi
 if test "$vde" = "yes" ; then
   echo "CONFIG_VDE=y" >> $config_host_mak
 fi
+if test "$netmap" = "yes" ; then
+  echo "CONFIG_NETMAP=y" >> $config_host_mak
+fi
 if test "$cap_ng" = "yes" ; then
   echo "CONFIG_LIBCAP=y" >> $config_host_mak
 fi

hmp-commands.hx

@@ -1190,7 +1190,7 @@ ETEXI
     {
         .name       = "host_net_add",
         .args_type  = "device:s,opts:s?",
-        .params     = "tap|user|socket|vde|dump [options]",
+        .params     = "tap|user|socket|vde|netmap|dump [options]",
         .help       = "add host VLAN client",
         .mhandler.cmd = net_host_device_add,
     },
@@ -1218,7 +1218,7 @@ ETEXI
     {
         .name       = "netdev_add",
         .args_type  = "netdev:O",
-        .params     = "[user|tap|socket|hubport],id=str[,prop=value][,...]",
+        .params     = "[user|tap|socket|hubport|netmap],id=str[,prop=value][,...]",
         .help       = "add host network device",
         .mhandler.cmd = hmp_netdev_add,
     },

net/Makefile.objs

@@ -11,3 +11,4 @@ common-obj-$(CONFIG_AIX) += tap-aix.o
 common-obj-$(CONFIG_HAIKU) += tap-haiku.o
 common-obj-$(CONFIG_SLIRP) += slirp.o
 common-obj-$(CONFIG_VDE) += vde.o
+common-obj-$(CONFIG_NETMAP) += netmap.o

net/clients.h

@@ -52,4 +52,9 @@ int net_init_vde(const NetClientOptions *opts, const char *name,
                  NetClientState *peer);
 #endif
 
+#ifdef CONFIG_NETMAP
+int net_init_netmap(const NetClientOptions *opts, const char *name,
+                    NetClientState *peer);
+#endif
+
 #endif /* QEMU_NET_CLIENTS_H */

net/net.c

@@ -725,6 +725,9 @@ static int (* const net_client_init_fun[NET_CLIENT_OPTIONS_KIND_MAX])(
         [NET_CLIENT_OPTIONS_KIND_SOCKET]    = net_init_socket,
 #ifdef CONFIG_VDE
         [NET_CLIENT_OPTIONS_KIND_VDE]       = net_init_vde,
+#endif
+#ifdef CONFIG_NETMAP
+        [NET_CLIENT_OPTIONS_KIND_NETMAP]    = net_init_netmap,
 #endif
         [NET_CLIENT_OPTIONS_KIND_DUMP]      = net_init_dump,
 #ifdef CONFIG_NET_BRIDGE
@@ -757,6 +760,9 @@ static int net_client_init1(const void *object, int is_netdev, Error **errp)
 #ifdef CONFIG_VDE
         case NET_CLIENT_OPTIONS_KIND_VDE:
 #endif
+#ifdef CONFIG_NETMAP
+        case NET_CLIENT_OPTIONS_KIND_NETMAP:
+#endif
 #ifdef CONFIG_NET_BRIDGE
         case NET_CLIENT_OPTIONS_KIND_BRIDGE:
 #endif