Hi Shivaji,
(please see below)
On Wed, 23 Jul 2025, Shivaji Kant wrote:
Currently, the AF_XDP PMD attaches its XDP program using a fixed
set of flags,defaulting to `XDP_FLAGS_UPDATE_IF_NOEXIST`. This lacks
flexibility for users who might need to explicitly control the XDP
mode based on their specific hardware capabilities or performance
requirements.
This patch introduces a new vdev argument, `mode`, for the `net_af_xdp`
PMD. This argument allows users to explicitly specify the desired
XDP program attachment mode:
`drv` (XDP_FLAGS_DRV_MODE),
`skb` (XDP_FLAGS_SKB_MODE),
`hw` (XDP_FLAGS_HW_MODE).
(If needed more can be added)
This change provides greater control and flexibility for users to
fine-tune AF_XDP behavior, enabling them to leverage native driver
or hardware offload capabilities when available, or fall back to
generic SKB mode for broader compatibility.
Signed-off-by: Shivaji Kant <shivajik...@google.com>
---
drivers/net/af_xdp/rte_eth_af_xdp.c | 61 +++++++++++++++++++++++++----
1 file changed, 54 insertions(+), 7 deletions(-)
diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c
b/drivers/net/af_xdp/rte_eth_af_xdp.c
index 5f65850a27..e39f2b4935 100644
--- a/drivers/net/af_xdp/rte_eth_af_xdp.c
+++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
@@ -104,6 +104,8 @@ RTE_LOG_REGISTER_DEFAULT(af_xdp_logtype, NOTICE);
static int afxdp_dev_count;
+static __u32 mode_flag = XDP_FLAGS_UPDATE_IF_NOEXIST;
If one seeks to add a per-device argument, then why is this static/driver-wide?
This belongs in 'struct pmd_internals'.
Thank you.
+
/* Message header to synchronize fds via IPC */
struct ipc_hdr {
char port_name[RTE_DEV_NAME_MAX_LEN];
@@ -198,6 +200,26 @@ struct pmd_process_private {
#define ETH_AF_XDP_USE_CNI_ARG "use_cni"
#define ETH_AF_XDP_USE_PINNED_MAP_ARG "use_pinned_map"
#define ETH_AF_XDP_DP_PATH_ARG "dp_path"
+#define ETH_AF_XDP_MODE_ARG "mode"
+
+/* Define different modes for af_xdp prog to attach */
+#define ETH_AF_XDP_DRV_MODE_ARG "drv"
+#define ETH_AF_XDP_SKB_MODE_ARG "skb"
+#define ETH_AF_XDP_HW_MODE_ARG "hw"
+#define ETH_AF_XDP_NUM_MODE_ARG 3
+
+static const char * const mode_arguments[] = {
+ ETH_AF_XDP_DRV_MODE_ARG,
+ ETH_AF_XDP_SKB_MODE_ARG,
+ ETH_AF_XDP_HW_MODE_ARG,
+ NULL
+};
+
+static const unsigned int mode_flags[] = {
+ XDP_FLAGS_DRV_MODE,
+ XDP_FLAGS_SKB_MODE,
+ XDP_FLAGS_HW_MODE
+};
static const char * const valid_arguments[] = {
ETH_AF_XDP_IFACE_ARG,
@@ -210,6 +232,7 @@ static const char * const valid_arguments[] = {
ETH_AF_XDP_USE_CNI_ARG,
ETH_AF_XDP_USE_PINNED_MAP_ARG,
ETH_AF_XDP_DP_PATH_ARG,
+ ETH_AF_XDP_MODE_ARG,
NULL
};
@@ -950,14 +973,14 @@ remove_xdp_program(struct pmd_internals *internals)
uint32_t curr_prog_id = 0;
int ret;
- ret = bpf_xdp_query_id(internals->if_index, XDP_FLAGS_UPDATE_IF_NOEXIST,
+ ret = bpf_xdp_query_id(internals->if_index, mode_flag,
&curr_prog_id);
if (ret != 0) {
AF_XDP_LOG_LINE(ERR, "bpf_xdp_query_id failed");
return ret;
}
- ret = bpf_xdp_detach(internals->if_index, XDP_FLAGS_UPDATE_IF_NOEXIST,
+ ret = bpf_xdp_detach(internals->if_index, mode_flag,
NULL);
if (ret != 0)
AF_XDP_LOG_LINE(ERR, "bpf_xdp_detach failed");
@@ -978,14 +1001,14 @@ remove_xdp_program(struct pmd_internals *internals)
int ret;
ret = bpf_get_link_xdp_id(internals->if_index, &curr_prog_id,
- XDP_FLAGS_UPDATE_IF_NOEXIST);
+ mode_flag);
if (ret != 0) {
AF_XDP_LOG_LINE(ERR, "bpf_get_link_xdp_id failed");
return ret;
}
ret = bpf_set_link_xdp_fd(internals->if_index, -1,
- XDP_FLAGS_UPDATE_IF_NOEXIST);
+ mode_flag);
if (ret != 0)
AF_XDP_LOG_LINE(ERR, "bpf_set_link_xdp_fd failed");
return ret;
@@ -1328,7 +1351,7 @@ load_custom_xdp_prog(const char *prog_path, int if_index,
struct bpf_map **map)
/* Link the program with the given network device */
ret = link_xdp_prog_with_dev(if_index, prog_fd,
- XDP_FLAGS_UPDATE_IF_NOEXIST);
+ mode_flag);
if (ret) {
AF_XDP_LOG_LINE(ERR, "Failed to set prog fd %d on interface",
prog_fd);
@@ -1679,7 +1702,7 @@ xsk_configure(struct pmd_internals *internals, struct
pkt_rx_queue *rxq,
cfg.rx_size = ring_size;
cfg.tx_size = ring_size;
cfg.libbpf_flags = 0;
- cfg.xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
+ cfg.xdp_flags = mode_flag;
cfg.bind_flags = 0;
/* Force AF_XDP socket into copy mode when users want it */
@@ -2017,6 +2040,25 @@ parse_name_arg(const char *key __rte_unused,
return 0;
}
+/** parse name argument */
+static int
+parse_mode_arg(const char *key __rte_unused,
+ const char *value, void *extra_args)
+{
+ unsigned int *mode = extra_args;
+ unsigned int i;
+
+ for (i = 0; i < ETH_AF_XDP_NUM_MODE_ARG; i++) {
+ if (strcmp(value, mode_arguments[i]) == 0) {
+ *mode |= mode_flags[i];
+ return 0;
+ }
+ }
+
+ AF_XDP_LOG_LINE(ERR, "Invalid af_xdp mode, choose correct mode to attach
af_xdp program.");
+ return -EINVAL;
+}
+
/** parse xdp prog argument */
static int
parse_prog_arg(const char *key __rte_unused,
@@ -2147,6 +2189,10 @@ parse_parameters(struct rte_kvargs *kvlist, char
*if_name, int *start_queue,
ret = rte_kvargs_process(kvlist, ETH_AF_XDP_DP_PATH_ARG,
&parse_prog_arg, dp_path);
+
+ ret = rte_kvargs_process(kvlist, ETH_AF_XDP_MODE_ARG,
+ &parse_mode_arg, &mode_flag);
+
if (ret < 0)
goto free_kvlist;
@@ -2587,4 +2633,5 @@ RTE_PMD_REGISTER_PARAM_STRING(net_af_xdp,
"force_copy=<int> "
"use_cni=<int> "
"use_pinned_map=<int> "
- "dp_path=<string> ");
+ "dp_path=<string> "
+ "mode=<string> ");
--
2.50.0.727.gbf7dc18ff4-goog
