Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 net.c           |    8 ++++++++
 net/tap.c       |   29 +++++++++++++++++++++++++++++
 qemu-options.hx |    4 +++-
 3 files changed, 40 insertions(+), 1 deletions(-)

diff --git a/net.c b/net.c
index 6ef93e6..b942d03 100644
--- a/net.c
+++ b/net.c
@@ -976,6 +976,14 @@ static struct {
                 .name = "vnet_hdr",
                 .type = QEMU_OPT_BOOL,
                 .help = "enable the IFF_VNET_HDR flag on the tap interface"
+            }, {
+                .name = "vhost",
+                .type = QEMU_OPT_BOOL,
+                .help = "enable vhost-net network accelerator",
+            }, {
+                .name = "vhostfd",
+                .type = QEMU_OPT_STRING,
+                .help = "file descriptor of an already opened vhost net device",
             },
 #endif /* _WIN32 */
             { /* end of list */ }
diff --git a/net/tap.c b/net/tap.c
index 7e9ca79..d9f2e41 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -41,6 +41,8 @@
 
 #include "net/tap-linux.h"
 
+#include "hw/vhost_net.h"
+
 /* Maximum GSO packet size (64k) plus plenty of room for
  * the ethernet and virtio_net headers
  */
@@ -57,6 +59,7 @@ typedef struct TAPState {
     unsigned int has_vnet_hdr : 1;
     unsigned int using_vnet_hdr : 1;
     unsigned int has_ufo: 1;
+    struct vhost_net *vhost_net;
 } TAPState;
 
 static int launch_script(const char *setup_script, const char *ifname, int fd);
@@ -252,6 +255,10 @@ static void tap_cleanup(VLANClientState *nc)
 {
     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 
+    if (s->vhost_net) {
+        vhost_net_cleanup(s->vhost_net);
+    }
+
     qemu_purge_queued_packets(nc);
 
     if (s->down_script[0])
@@ -307,6 +314,7 @@ static TAPState *net_tap_fd_init(VLANState *vlan,
     s->has_ufo = tap_probe_has_ufo(s->fd);
     tap_set_offload(&s->nc, 0, 0, 0, 0, 0);
     tap_read_poll(s, 1);
+    s->vhost_net = NULL;
     return s;
 }
 
@@ -456,5 +464,26 @@ int net_init_tap(QemuOpts *opts, Monitor *mon, const char *name, VLANState *vlan
         }
     }
 
+    if (qemu_opt_get_bool(opts, "vhost", 0)) {
+        int vhostfd, r;
+        if (qemu_opt_get(opts, "vhostfd")) {
+            r = net_handle_fd_param(mon, qemu_opt_get(opts, "vhostfd"));
+            if (r == -1) {
+                return -1;
+            }
+            vhostfd = r;
+        } else {
+            vhostfd = -1;
+        }
+        s->vhost_net = vhost_net_init(&s->nc, vhostfd);
+        if (!s->vhost_net) {
+            qemu_error("vhost-net requested but could not be initialized\n");
+            return -1;
+        }
+    } else if (qemu_opt_get(opts, "vhostfd")) {
+        qemu_error("vhostfd= is not valid without vhost\n");
+        return -1;
+    }
+
     return 0;
 }
diff --git a/qemu-options.hx b/qemu-options.hx
index ca73ba5..2b3d9b8 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -814,7 +814,7 @@ DEF("net", HAS_ARG, QEMU_OPTION_net,
     "-net tap[,vlan=n][,name=str],ifname=name\n"
     "                connect the host TAP network interface to VLAN 'n'\n"
 #else
-    "-net tap[,vlan=n][,name=str][,fd=h][,ifname=name][,script=file][,downscript=dfile][,sndbuf=nbytes][,vnet_hdr=on|off]\n"
+    "-net tap[,vlan=n][,name=str][,fd=h][,ifname=name][,script=file][,downscript=dfile][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off][,vhostfd=h]\n"
     "                connect the host TAP network interface to VLAN 'n' and use the\n"
     "                network scripts 'file' (default=%s)\n"
     "                and 'dfile' (default=%s);\n"
@@ -824,6 +824,8 @@ DEF("net", HAS_ARG, QEMU_OPTION_net,
     "                default of 'sndbuf=1048576' can be disabled using 'sndbuf=0'\n"
     "                use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag; use\n"
     "                vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n"
+    "                use vhost=on to enable experimental in kernel accelerator\n"
+    "                use 'vhostfd=h' to connect to an already opened vhost net device\n"
 #endif
     "-net socket[,vlan=n][,name=str][,fd=h][,listen=[host]:port][,connect=host:port]\n"
     "                connect the vlan 'n' to another VLAN using a socket connection\n"
-- 
1.6.6.144.g5c3af