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

# -----BEGIN PGP SIGNATURE-----
#
# iQEzBAABCAAdFiEEIV1G9IJGaJ7HfzVi7wSWWzmNYhEFAmh11cgACgkQ7wSWWzmN
# YhGZKAf+PZ3ZnOoHXd5z8hA5d9Xf+U/01YyPN+Q0NPLWVXhYZBeNhhYEnZwGeSwS
# n0YFTLiYIrcaSrt74QtBvUVCX7KoILRnzgoLquUnFBlI0BrR5pFKB70gHmLU3Dxw
# xOdxtIm/chfiicE39ziTfO28Cv0N1k9NCHsuMsydbhQL8kc/aRaMofizO8MjPLbr
# J8hf8N7jivh8fzH3F5vyglaNl2ijSkPm+XDQYAb04laGfdsIlYkmB7lB/17def2a
# S9gur484x5w+Yb2LNdyq/3IPzDqzlNbRGVcfTZS8FIc65R+5idIN+7lKHCffURrr
# W8zWFy1wA54hJoTxAq0nsf1TSvc9UA==
# =DiBC
# -----END PGP SIGNATURE-----
# gpg: Signature made Tue 15 Jul 2025 00:15:04 EDT
# gpg:                using RSA key 215D46F48246689EC77F3562EF04965B398D6211
# gpg: Good signature from "Jason Wang (Jason Wang on RedHat) <jasowang@redhat.com>" [full]
# Primary key fingerprint: 215D 46F4 8246 689E C77F  3562 EF04 965B 398D 6211

* 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>

1 files changed, 79 insertions, 18 deletions

diff --git a/net/af-xdp.c b/net/af-xdp.c
index d022534..14f302e 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;