Merge tag 'net-pull-request' of https://github.com/jasowang/qemu into staging

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* tag 'net-pull-request' of https://github.com/jasowang/qemu:
  net/af-xdp: Support pinned map path for AF_XDP sockets
  net/af-xdp: Fix up cleanup path upon failure in queue creation
  net/af-xdp: Remove XDP program cleanup logic

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

3 files changed, 119 insertions, 30 deletions

diff --git a/net/af-xdp.c b/net/af-xdp.c
index d022534d76..14f302ea21 100644
--- a/net/af-xdp.c
+++ b/net/af-xdp.c
@@ -49,9 +49,12 @@ typedef struct AFXDPState {
     char                 *buffer;
     struct xsk_umem      *umem;
 
-    uint32_t             n_queues;
     uint32_t             xdp_flags;
     bool                 inhibit;
+
+    char                 *map_path;
+    int                  map_fd;
+    uint32_t             map_start_index;
 } AFXDPState;
 
 #define AF_XDP_BATCH_SIZE 64
@@ -261,6 +264,7 @@ static void af_xdp_send(void *opaque)
 static void af_xdp_cleanup(NetClientState *nc)
 {
     AFXDPState *s = DO_UPCAST(AFXDPState, nc, nc);
+    int idx;
 
     qemu_purge_queued_packets(nc);
 
@@ -275,13 +279,17 @@ static void af_xdp_cleanup(NetClientState *nc)
     qemu_vfree(s->buffer);
     s->buffer = NULL;
 
-    /* Remove the program if it's the last open queue. */
-    if (!s->inhibit && nc->queue_index == s->n_queues - 1 && s->xdp_flags
-        && bpf_xdp_detach(s->ifindex, s->xdp_flags, NULL) != 0) {
-        fprintf(stderr,
-                "af-xdp: unable to remove XDP program from '%s', ifindex: %d\n",
-                s->ifname, s->ifindex);
+    if (s->map_fd >= 0) {
+        idx = nc->queue_index + s->map_start_index;
+        if (bpf_map_delete_elem(s->map_fd, &idx)) {
+            fprintf(stderr, "af-xdp: unable to remove AF_XDP socket from map"
+                    " %s\n", s->map_path);
+        }
+        close(s->map_fd);
+        s->map_fd = -1;
     }
+    g_free(s->map_path);
+    s->map_path = NULL;
 }
 
 static int af_xdp_umem_create(AFXDPState *s, int sock_fd, Error **errp)
@@ -345,7 +353,6 @@ static int af_xdp_socket_create(AFXDPState *s,
     };
     int queue_id, error = 0;
 
-    s->inhibit = opts->has_inhibit && opts->inhibit;
     if (s->inhibit) {
         cfg.libxdp_flags |= XSK_LIBXDP_FLAGS__INHIBIT_PROG_LOAD;
     }
@@ -396,6 +403,35 @@ static int af_xdp_socket_create(AFXDPState *s,
     return 0;
 }
 
+static int af_xdp_update_xsk_map(AFXDPState *s, Error **errp)
+{
+    int xsk_fd, idx, error = 0;
+
+    if (!s->map_path) {
+        return 0;
+    }
+
+    s->map_fd = bpf_obj_get(s->map_path);
+    if (s->map_fd < 0) {
+        error = errno;
+    } else {
+        xsk_fd = xsk_socket__fd(s->xsk);
+        idx = s->nc.queue_index + s->map_start_index;
+        if (bpf_map_update_elem(s->map_fd, &idx, &xsk_fd, 0)) {
+            error = errno;
+        }
+    }
+
+    if (error) {
+        error_setg_errno(errp, error,
+                         "failed to insert AF_XDP socket into map %s",
+                         s->map_path);
+        return -1;
+    }
+
+    return 0;
+}
+
 /* NetClientInfo methods. */
 static NetClientInfo net_af_xdp_info = {
     .type = NET_CLIENT_DRIVER_AF_XDP,
@@ -444,12 +480,14 @@ int net_init_af_xdp(const Netdev *netdev,
 {
     const NetdevAFXDPOptions *opts = &netdev->u.af_xdp;
     NetClientState *nc, *nc0 = NULL;
+    int32_t map_start_index;
     unsigned int ifindex;
     uint32_t prog_id = 0;
     g_autofree int *sock_fds = NULL;
     int64_t i, queues;
     Error *err = NULL;
     AFXDPState *s;
+    bool inhibit;
 
     ifindex = if_nametoindex(opts->ifname);
     if (!ifindex) {
@@ -465,8 +503,28 @@ int net_init_af_xdp(const Netdev *netdev,
         return -1;
     }
 
-    if ((opts->has_inhibit && opts->inhibit) != !!opts->sock_fds) {
-        error_setg(errp, "'inhibit=on' requires 'sock-fds' and vice versa");
+    inhibit = opts->has_inhibit && opts->inhibit;
+    if (inhibit && !opts->sock_fds && !opts->map_path) {
+        error_setg(errp, "'inhibit=on' requires 'sock-fds' or 'map-path'");
+        return -1;
+    }
+    if (!inhibit && (opts->sock_fds || opts->map_path)) {
+        error_setg(errp, "'sock-fds' and 'map-path' require 'inhibit=on'");
+        return -1;
+    }
+    if (opts->sock_fds && opts->map_path) {
+        error_setg(errp, "'sock-fds' and 'map-path' are mutually exclusive");
+        return -1;
+    }
+    if (!opts->map_path && opts->has_map_start_index) {
+        error_setg(errp, "'map-start-index' requires 'map-path'");
+        return -1;
+    }
+
+    map_start_index = opts->has_map_start_index ? opts->map_start_index : 0;
+    if (map_start_index < 0) {
+        error_setg(errp, "'map-start-index' cannot be negative (%d)",
+                   map_start_index);
         return -1;
     }
 
@@ -490,21 +548,23 @@ int net_init_af_xdp(const Netdev *netdev,
 
         pstrcpy(s->ifname, sizeof(s->ifname), opts->ifname);
         s->ifindex = ifindex;
-        s->n_queues = queues;
+        s->inhibit = inhibit;
+
+        s->map_path = g_strdup(opts->map_path);
+        s->map_start_index = map_start_index;
+        s->map_fd = -1;
 
-        if (af_xdp_umem_create(s, sock_fds ? sock_fds[i] : -1, errp)
-            || af_xdp_socket_create(s, opts, errp)) {
-            /* Make sure the XDP program will be removed. */
-            s->n_queues = i;
-            error_propagate(errp, err);
+        if (af_xdp_umem_create(s, sock_fds ? sock_fds[i] : -1, &err) ||
+            af_xdp_socket_create(s, opts, &err) ||
+            af_xdp_update_xsk_map(s, &err)) {
             goto err;
         }
     }
 
-    if (nc0) {
+    if (nc0 && !inhibit) {
         s = DO_UPCAST(AFXDPState, nc, nc0);
         if (bpf_xdp_query_id(s->ifindex, s->xdp_flags, &prog_id) || !prog_id) {
-            error_setg_errno(errp, errno,
+            error_setg_errno(&err, errno,
                              "no XDP program loaded on '%s', ifindex: %d",
                              s->ifname, s->ifindex);
             goto err;
@@ -518,6 +578,7 @@ int net_init_af_xdp(const Netdev *netdev,
 err:
     if (nc0) {
         qemu_del_net_client(nc0);
+        error_propagate(errp, err);
     }
 
     return -1;
diff --git a/qapi/net.json b/qapi/net.json
index 0f766041a3..1f40bf46bb 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -567,25 +567,34 @@
 #     (default: 0).
 #
 # @inhibit: Don't load a default XDP program, use one already loaded
-#     to the interface (default: false).  Requires @sock-fds.
+#     to the interface (default: false).  Requires @sock-fds or @map-path.
 #
 # @sock-fds: A colon (:) separated list of file descriptors for
 #     already open but not bound AF_XDP sockets in the queue order.
 #     One fd per queue.  These descriptors should already be added
-#     into XDP socket map for corresponding queues.  Requires
-#     @inhibit.
+#     into XDP socket map for corresponding queues.  @sock-fds and
+#     @map-path are mutually exclusive.  Requires @inhibit.
+#
+# @map-path: The path to a pinned xsk map to push file descriptors
+#     for bound AF_XDP sockets into.  @map-path and @sock-fds are
+#     mutually exclusive.  Requires @inhibit.  (Since 10.1)
+#
+# @map-start-index: Use @map-path to insert xsk sockets starting from
+#     this index number (default: 0).  Requires @map-path.  (Since 10.1)
 #
 # Since: 8.2
 ##
 { 'struct': 'NetdevAFXDPOptions',
   'data': {
-    'ifname':       'str',
-    '*mode':        'AFXDPMode',
-    '*force-copy':  'bool',
-    '*queues':      'int',
-    '*start-queue': 'int',
-    '*inhibit':     'bool',
-    '*sock-fds':    'str' },
+    'ifname':           'str',
+    '*mode':            'AFXDPMode',
+    '*force-copy':      'bool',
+    '*queues':          'int',
+    '*start-queue':     'int',
+    '*inhibit':         'bool',
+    '*sock-fds':        'str',
+    '*map-path':        'str',
+    '*map-start-index': 'int32' },
   'if': 'CONFIG_AF_XDP' }
 
 ##
diff --git a/qemu-options.hx b/qemu-options.hx
index cc5efdc956..fe9beb2c27 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2934,6 +2934,7 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
 #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"
+    "         [,map-path=/path/to/socket/map][,map-start-index=i]\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"
@@ -2941,6 +2942,8 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
     "                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 'map-path' to provide the socket map location to populate AF_XDP sockets with,\n"
+    "                  and use 'map-start-index' to specify the starting index for the map (default: 0) (Since 10.1)\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
@@ -3764,7 +3767,7 @@ 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]``
+``-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][,map-path=/path/to/socket/map][,map-start-index=i]``
     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,
@@ -3804,7 +3807,8 @@ SRST
             -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
+    should be set to 'on'.  Either 'sock-fds' or 'map-path' can be used with
+    'inhibit' enabled.  'sock-fds' can be 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.
 
@@ -3813,6 +3817,21 @@ SRST
         |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
 
+    For the 'inhibit' option set to 'on' used together with 'map-path' it is
+    expected that the XDP program with the socket map is already loaded on
+    the networking device and the map pinned into BPF file system.  The path
+    to the pinned map is then passed to QEMU which then creates the file
+    descriptors and inserts them into the existing socket map.
+
+    .. parsed-literal::
+
+        |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\
+            -netdev af-xdp,id=n1,ifname=eth0,queues=2,inhibit=on,map-path=/sys/fs/bpf/xsks_map
+
+    Additionally, 'map-start-index' can be used to specify the start offset
+    for insertion into the socket map.  The combination of 'map-path' and
+    'sock-fds' together is not supported.
+
 ``-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