1 files changed, 271 insertions, 0 deletions
diff --git a/drivers/net/ethernet/intel/libeth/xsk.c b/drivers/net/ethernet/intel/libeth/xsk.c
new file mode 100644
index 000000000000..846e902e31b6
--- /dev/null
+++ b/drivers/net/ethernet/intel/libeth/xsk.c
@@ -0,0 +1,271 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2025 Intel Corporation */
+
+#define DEFAULT_SYMBOL_NAMESPACE	"LIBETH_XDP"
+
+#include <linux/export.h>
+
+#include <net/libeth/xsk.h>
+
+#include "priv.h"
+
+/* ``XDP_TX`` bulking */
+
+void __cold libeth_xsk_tx_return_bulk(const struct libeth_xdp_tx_frame *bq,
+				      u32 count)
+{
+	for (u32 i = 0; i < count; i++)
+		libeth_xsk_buff_free_slow(bq[i].xsk);
+}
+
+/* XSk TMO */
+
+const struct xsk_tx_metadata_ops libeth_xsktmo_slow = {
+	.tmo_request_checksum		= libeth_xsktmo_req_csum,
+};
+
+/* Rx polling path */
+
+/**
+ * libeth_xsk_buff_free_slow - free an XSk Rx buffer
+ * @xdp: buffer to free
+ *
+ * Slowpath version of xsk_buff_free() to be used on exceptions, cleanups etc.
+ * to avoid unwanted inlining.
+ */
+void libeth_xsk_buff_free_slow(struct libeth_xdp_buff *xdp)
+{
+	xsk_buff_free(&xdp->base);
+}
+EXPORT_SYMBOL_GPL(libeth_xsk_buff_free_slow);
+
+/**
+ * libeth_xsk_buff_add_frag - add frag to XSk Rx buffer
+ * @head: head buffer
+ * @xdp: frag buffer
+ *
+ * External helper used by libeth_xsk_process_buff(), do not call directly.
+ * Frees both main and frag buffers on error.
+ *
+ * Return: main buffer with attached frag on success, %NULL on error (no space
+ * for a new frag).
+ */
+struct libeth_xdp_buff *libeth_xsk_buff_add_frag(struct libeth_xdp_buff *head,
+						 struct libeth_xdp_buff *xdp)
+{
+	if (!xsk_buff_add_frag(&head->base, &xdp->base))
+		goto free;
+
+	return head;
+
+free:
+	libeth_xsk_buff_free_slow(xdp);
+	libeth_xsk_buff_free_slow(head);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(libeth_xsk_buff_add_frag);
+
+/**
+ * libeth_xsk_buff_stats_frags - update onstack RQ stats with XSk frags info
+ * @rs: onstack stats to update
+ * @xdp: buffer to account
+ *
+ * External helper used by __libeth_xsk_run_pass(), do not call directly.
+ * Adds buffer's frags count and total len to the onstack stats.
+ */
+void libeth_xsk_buff_stats_frags(struct libeth_rq_napi_stats *rs,
+				 const struct libeth_xdp_buff *xdp)
+{
+	libeth_xdp_buff_stats_frags(rs, xdp);
+}
+EXPORT_SYMBOL_GPL(libeth_xsk_buff_stats_frags);
+
+/**
+ * __libeth_xsk_run_prog_slow - process the non-``XDP_REDIRECT`` verdicts
+ * @xdp: buffer to process
+ * @bq: Tx bulk for queueing on ``XDP_TX``
+ * @act: verdict to process
+ * @ret: error code if ``XDP_REDIRECT`` failed
+ *
+ * External helper used by __libeth_xsk_run_prog(), do not call directly.
+ * ``XDP_REDIRECT`` is the most common and hottest verdict on XSk, thus
+ * it is processed inline. The rest goes here for out-of-line processing,
+ * together with redirect errors.
+ *
+ * Return: libeth_xdp XDP prog verdict.
+ */
+u32 __libeth_xsk_run_prog_slow(struct libeth_xdp_buff *xdp,
+			       const struct libeth_xdp_tx_bulk *bq,
+			       enum xdp_action act, int ret)
+{
+	switch (act) {
+	case XDP_DROP:
+		xsk_buff_free(&xdp->base);
+
+		return LIBETH_XDP_DROP;
+	case XDP_TX:
+		return LIBETH_XDP_TX;
+	case XDP_PASS:
+		return LIBETH_XDP_PASS;
+	default:
+		break;
+	}
+
+	return libeth_xdp_prog_exception(bq, xdp, act, ret);
+}
+EXPORT_SYMBOL_GPL(__libeth_xsk_run_prog_slow);
+
+/**
+ * libeth_xsk_prog_exception - handle XDP prog exceptions on XSk
+ * @xdp: buffer to process
+ * @act: verdict returned by the prog
+ * @ret: error code if ``XDP_REDIRECT`` failed
+ *
+ * Internal. Frees the buffer and, if the queue uses XSk wakeups, stop the
+ * current NAPI poll when there are no free buffers left.
+ *
+ * Return: libeth_xdp's XDP prog verdict.
+ */
+u32 __cold libeth_xsk_prog_exception(struct libeth_xdp_buff *xdp,
+				     enum xdp_action act, int ret)
+{
+	const struct xdp_buff_xsk *xsk;
+	u32 __ret = LIBETH_XDP_DROP;
+
+	if (act != XDP_REDIRECT)
+		goto drop;
+
+	xsk = container_of(&xdp->base, typeof(*xsk), xdp);
+	if (xsk_uses_need_wakeup(xsk->pool) && ret == -ENOBUFS)
+		__ret = LIBETH_XDP_ABORTED;
+
+drop:
+	libeth_xsk_buff_free_slow(xdp);
+
+	return __ret;
+}
+
+/* Refill */
+
+/**
+ * libeth_xskfq_create - create an XSkFQ
+ * @fq: fill queue to initialize
+ *
+ * Allocates the FQEs and initializes the fields used by libeth_xdp: number
+ * of buffers to refill, refill threshold and buffer len.
+ *
+ * Return: %0 on success, -errno otherwise.
+ */
+int libeth_xskfq_create(struct libeth_xskfq *fq)
+{
+	fq->fqes = kvcalloc_node(fq->count, sizeof(*fq->fqes), GFP_KERNEL,
+				 fq->nid);
+	if (!fq->fqes)
+		return -ENOMEM;
+
+	fq->pending = fq->count;
+	fq->thresh = libeth_xdp_queue_threshold(fq->count);
+	fq->buf_len = xsk_pool_get_rx_frame_size(fq->pool);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(libeth_xskfq_create);
+
+/**
+ * libeth_xskfq_destroy - destroy an XSkFQ
+ * @fq: fill queue to destroy
+ *
+ * Zeroes the used fields and frees the FQEs array.
+ */
+void libeth_xskfq_destroy(struct libeth_xskfq *fq)
+{
+	fq->buf_len = 0;
+	fq->thresh = 0;
+	fq->pending = 0;
+
+	kvfree(fq->fqes);
+}
+EXPORT_SYMBOL_GPL(libeth_xskfq_destroy);
+
+/* .ndo_xsk_wakeup */
+
+static void libeth_xsk_napi_sched(void *info)
+{
+	__napi_schedule_irqoff(info);
+}
+
+/**
+ * libeth_xsk_init_wakeup - initialize libeth XSk wakeup structure
+ * @csd: struct to initialize
+ * @napi: NAPI corresponding to this queue
+ *
+ * libeth_xdp uses inter-processor interrupts to perform XSk wakeups. In order
+ * to do that, the corresponding CSDs must be initialized when creating the
+ * queues.
+ */
+void libeth_xsk_init_wakeup(call_single_data_t *csd, struct napi_struct *napi)
+{
+	INIT_CSD(csd, libeth_xsk_napi_sched, napi);
+}
+EXPORT_SYMBOL_GPL(libeth_xsk_init_wakeup);
+
+/**
+ * libeth_xsk_wakeup - perform an XSk wakeup
+ * @csd: CSD corresponding to the queue
+ * @qid: the stack queue index
+ *
+ * Try to mark the NAPI as missed first, so that it could be rescheduled.
+ * If it's not, schedule it on the corresponding CPU using IPIs (or directly
+ * if already running on it).
+ */
+void libeth_xsk_wakeup(call_single_data_t *csd, u32 qid)
+{
+	struct napi_struct *napi = csd->info;
+
+	if (napi_if_scheduled_mark_missed(napi) ||
+	    unlikely(!napi_schedule_prep(napi)))
+		return;
+
+	if (unlikely(qid >= nr_cpu_ids))
+		qid %= nr_cpu_ids;
+
+	if (qid != raw_smp_processor_id() && cpu_online(qid))
+		smp_call_function_single_async(qid, csd);
+	else
+		__napi_schedule(napi);
+}
+EXPORT_SYMBOL_GPL(libeth_xsk_wakeup);
+
+/* Pool setup */
+
+#define LIBETH_XSK_DMA_ATTR					\
+	(DMA_ATTR_WEAK_ORDERING | DMA_ATTR_SKIP_CPU_SYNC)
+
+/**
+ * libeth_xsk_setup_pool - setup or destroy an XSk pool for a queue
+ * @dev: target &net_device
+ * @qid: stack queue index to configure
+ * @enable: whether to enable or disable the pool
+ *
+ * Check that @qid is valid and then map or unmap the pool.
+ *
+ * Return: %0 on success, -errno otherwise.
+ */
+int libeth_xsk_setup_pool(struct net_device *dev, u32 qid, bool enable)
+{
+	struct xsk_buff_pool *pool;
+
+	pool = xsk_get_pool_from_qid(dev, qid);
+	if (!pool)
+		return -EINVAL;
+
+	if (enable)
+		return xsk_pool_dma_map(pool, dev->dev.parent,
+					LIBETH_XSK_DMA_ATTR);
+	else
+		xsk_pool_dma_unmap(pool, LIBETH_XSK_DMA_ATTR);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(libeth_xsk_setup_pool);