Extend inhibit=on setting with the option to specify a pinned XSK map
path along with a starting index (default 0) to push the created XSK
sockets into. Example usage:
# ./build/qemu-system-x86_64 [...] \
-netdev
af-xdp,ifname=eth0,id=net0,mode=native,queues=2,inhibit=on,map-path=/sys/fs/bpf/foo,map-start-index=2
-device virtio-net-pci,netdev=net0 [...]
This is useful for the case where an existing XDP program with XSK map
is present on the AF_XDP supported phys device and the XSK map not yet
populated. Qemu will then push the XSK sockets into the specified map.
Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
Cc: Ilya Maximets <i.maxim...@ovn.org>
Cc: Jason Wang <jasow...@redhat.com>
Cc: Anton Protopopov <as...@isovalent.com>
---
net/af-xdp.c | 63 +++++++++++++++++++++++++++++++++++++++++++++------
qapi/net.json | 24 +++++++++++++-------
2 files changed, 72 insertions(+), 15 deletions(-)
diff --git a/net/af-xdp.c b/net/af-xdp.c
index 01c5fb914e..ddc52f1307 100644
--- a/net/af-xdp.c
+++ b/net/af-xdp.c
@@ -51,6 +51,8 @@ typedef struct AFXDPState {
uint32_t n_queues;
uint32_t xdp_flags;
+ char *map_path;
+ uint32_t map_start_index;
bool inhibit;
} AFXDPState;
@@ -261,6 +263,7 @@ static void af_xdp_send(void *opaque)
static void af_xdp_cleanup(NetClientState *nc)
{
AFXDPState *s = DO_UPCAST(AFXDPState, nc, nc);
+ int pin_fd, idx;
qemu_purge_queued_packets(nc);
@@ -282,6 +285,22 @@ static void af_xdp_cleanup(NetClientState *nc)
"af-xdp: unable to remove XDP program from '%s', ifindex:
%d\n",
s->ifname, s->ifindex);
}
+ if (s->map_path) {
+ pin_fd = bpf_obj_get(s->map_path);
+ if (pin_fd < 0) {
+ fprintf(stderr,
+ "af-xdp: unable to remove %s's XSK sockets from '%s', ifindex:
%d\n",
+ s->ifname, s->map_path, s->ifindex);
+ } else {
+ idx = nc->queue_index;
+ if (s->map_start_index > 0) {
+ idx += s->map_start_index;
+ }
+ bpf_map_delete_elem(pin_fd, &idx);
+ close(pin_fd);
+ }
+ }
+ g_free(s->map_path);
}
static int af_xdp_umem_create(AFXDPState *s, int sock_fd, Error **errp)
@@ -343,7 +362,7 @@ static int af_xdp_socket_create(AFXDPState *s,
.bind_flags = XDP_USE_NEED_WAKEUP,
.xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST,
};
- int queue_id, error = 0;
+ int queue_id, pin_fd, xsk_fd, idx, error = 0;
s->inhibit = opts->has_inhibit && opts->inhibit;
if (s->inhibit) {
@@ -384,6 +403,23 @@ static int af_xdp_socket_create(AFXDPState *s,
}
}
+ if (!error && s->map_path) {
+ pin_fd = bpf_obj_get(s->map_path);
+ if (pin_fd < 0) {
+ error = errno;
+ } else {
+ xsk_fd = xsk_socket__fd(s->xsk);
+ idx = s->nc.queue_index;
+ if (s->map_start_index) {
+ idx += s->map_start_index;
+ }
+ if (bpf_map_update_elem(pin_fd, &idx, &xsk_fd, 0)) {
+ error = errno;
+ }
+ close(pin_fd);
+ }
+ }
+
if (error) {
error_setg_errno(errp, error,
"failed to create AF_XDP socket for %s queue_id: %d",
@@ -465,8 +501,8 @@ 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");
+ if ((opts->has_inhibit && opts->inhibit) != !!(opts->sock_fds ||
opts->map_path)) {
+ error_setg(errp, "'inhibit=on' requires 'sock-fds' or 'map-path' and
vice versa");
return -1;
}
@@ -491,6 +527,12 @@ int net_init_af_xdp(const Netdev *netdev,
pstrcpy(s->ifname, sizeof(s->ifname), opts->ifname);
s->ifindex = ifindex;
s->n_queues = queues;
+ if (opts->map_path) {
+ s->map_path = g_strdup(opts->map_path);
+ if (opts->has_map_start_index && opts->map_start_index > 0) {
+ s->map_start_index = opts->map_start_index;
+ }
+ }
if (af_xdp_umem_create(s, sock_fds ? sock_fds[i] : -1, errp)
|| af_xdp_socket_create(s, opts, errp)) {
@@ -504,10 +546,17 @@ int net_init_af_xdp(const Netdev *netdev,
if (nc0) {
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,
- "no XDP program loaded on '%s', ifindex: %d",
- s->ifname, s->ifindex);
- goto err;
+ if (!s->map_path) {
+ error_setg_errno(errp, errno,
+ "no XDP program loaded on '%s', ifindex: %d",
+ s->ifname, s->ifindex);
+ goto err;
+ } else {
+ warn_report("no XDP program loaded on '%s', ifindex: %d, "
+ "only %"PRIi64" XSK socket%s loaded into map %s at
this point",
+ s->ifname, s->ifindex, queues, queues > 1 ? "s" :
"",
+ s->map_path);
+ }
}
}
diff --git a/qapi/net.json b/qapi/net.json
index 310cc4fd19..c750b805e8 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -454,7 +454,7 @@
# (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.
@@ -462,17 +462,25 @@
# into XDP socket map for corresponding queues. Requires
# @inhibit.
#
+# @map-path: The path to a pinned xsk map to push file descriptors
+# for bound AF_XDP sockets into. Requires @inhibit.
+#
+# @map-start-index: Use @map-path to insert xsk sockets starting from
+# this index number (default: 0). Requires @map-path.
+#
# 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': 'int' },
'if': 'CONFIG_AF_XDP' }
##
--
2.43.0
