[PATCH net-next v2 09/21] virtio_net: xsk: bind/unbind xsk

Xuan Zhuo
Tue, 07 Nov 2023 03:12:15 -0000

This patch implement the logic of bind/unbind xsk pool to sq and rq.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/net/virtio/Makefile     |   2 +-
 drivers/net/virtio/main.c       |  11 +-
 drivers/net/virtio/virtio_net.h |  16 +++
 drivers/net/virtio/xsk.c        | 187 ++++++++++++++++++++++++++++++++
 drivers/net/virtio/xsk.h        |   7 ++
 5 files changed, 216 insertions(+), 7 deletions(-)
 create mode 100644 drivers/net/virtio/xsk.c
 create mode 100644 drivers/net/virtio/xsk.h

diff --git a/drivers/net/virtio/Makefile b/drivers/net/virtio/Makefile
index 15ed7c97fd4f..8c2a884d2dba 100644
--- a/drivers/net/virtio/Makefile
+++ b/drivers/net/virtio/Makefile
@@ -5,4 +5,4 @@

 obj-$(CONFIG_VIRTIO_NET) += virtio_net.o

-virtio_net-y := main.o
+virtio_net-y := main.o xsk.o
diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
index f052db459156..c4601784b6d1 100644
--- a/drivers/net/virtio/main.c
+++ b/drivers/net/virtio/main.c
@@ -8,7 +8,6 @@
 #include <linux/etherdevice.h>
 #include <linux/module.h>
 #include <linux/virtio.h>
-#include <linux/virtio_net.h>
 #include <linux/bpf.h>
 #include <linux/bpf_trace.h>
 #include <linux/scatterlist.h>
@@ -23,6 +22,7 @@
 #include <net/netdev_rx_queue.h>

 #include "virtio_net.h"
+#include "xsk.h"

 static int napi_weight = NAPI_POLL_WEIGHT;
 module_param(napi_weight, int, 0444);
@@ -150,9 +150,6 @@ struct virtio_net_common_hdr {
 	};
 };

-static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf);
-static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf);
-
 static bool is_xdp_frame(void *ptr)
 {
 	return (unsigned long)ptr & VIRTIO_XDP_FLAG;
@@ -3797,6 +3794,8 @@ static int virtnet_xdp(struct net_device *dev, struct
netdev_bpf *xdp)
 	switch (xdp->command) {
 	case XDP_SETUP_PROG:
 		return virtnet_xdp_set(dev, xdp->prog, xdp->extack);
+	case XDP_SETUP_XSK_POOL:
+		return virtnet_xsk_pool_setup(dev, xdp);
 	default:
 		return -EINVAL;
 	}
@@ -3982,7 +3981,7 @@ static void free_receive_page_frags(struct virtnet_info
*vi)
 		}
 }

-static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
+void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
 {
 	struct virtnet_info *vi = vq->vdev->priv;
 	struct virtnet_sq *sq;
@@ -4003,7 +4002,7 @@ static void virtnet_sq_free_unused_buf(struct virtqueue
*vq, void *buf)
 	}
 }

-static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)
+void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)
 {
 	struct virtnet_info *vi = vq->vdev->priv;
 	struct virtnet_rq *rq;
diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
index ce806afb6d64..98ba23cfdb20 100644
--- a/drivers/net/virtio/virtio_net.h
+++ b/drivers/net/virtio/virtio_net.h
@@ -5,6 +5,8 @@

 #include <linux/ethtool.h>
 #include <linux/average.h>
+#include <linux/virtio_net.h>
+#include <net/xdp_sock_drv.h>

 /* RX packet size EWMA. The average packet size is used to determine the packet
  * buffer size when refilling RX rings. As the entire RX ring may be refilled
@@ -83,6 +85,11 @@ struct virtnet_sq {
 	bool do_dma;

 	struct virtnet_sq_dma_head dmainfo;
+	struct {
+		struct xsk_buff_pool *pool;
+
+		dma_addr_t hdr_dma_address;
+	} xsk;
 };

 /* Internal representation of a receive virtqueue */
@@ -123,6 +130,13 @@ struct virtnet_rq {

 	/* Do dma by self */
 	bool do_dma;
+
+	struct {
+		struct xsk_buff_pool *pool;
+
+		/* xdp rxq used by xsk */
+		struct xdp_rxq_info xdp_rxq;
+	} xsk;
 };

 struct virtnet_info {
@@ -211,4 +225,6 @@ void virtnet_rx_pause(struct virtnet_info *vi, struct
virtnet_rq *rq);
 void virtnet_rx_resume(struct virtnet_info *vi, struct virtnet_rq *rq);
 void virtnet_tx_pause(struct virtnet_info *vi, struct virtnet_sq *sq);
 void virtnet_tx_resume(struct virtnet_info *vi, struct virtnet_sq *sq);
+void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf);
+void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf);
 #endif
diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
new file mode 100644
index 000000000000..8b397787603f
--- /dev/null
+++ b/drivers/net/virtio/xsk.c
@@ -0,0 +1,187 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * virtio-net xsk
+ */
+
+#include "virtio_net.h"
+
+static struct virtio_net_hdr_mrg_rxbuf xsk_hdr;
+
+static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct virtnet_rq
*rq,
+				    struct xsk_buff_pool *pool)
+{
+	int err, qindex;
+
+	qindex = rq - vi->rq;
+
+	if (pool) {
+		err = xdp_rxq_info_reg(&rq->xsk.xdp_rxq, vi->dev, qindex,
rq->napi.napi_id);
+		if (err < 0)
+			return err;
+
+		err = xdp_rxq_info_reg_mem_model(&rq->xsk.xdp_rxq,
+						 MEM_TYPE_XSK_BUFF_POOL, NULL);
+		if (err < 0) {
+			xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
+			return err;
+		}
+
+		xsk_pool_set_rxq_info(pool, &rq->xsk.xdp_rxq);
+	}
+
+	virtnet_rx_pause(vi, rq);
+
+	err = virtqueue_reset(rq->vq, virtnet_rq_free_unused_buf);
+	if (err) {
+		netdev_err(vi->dev, "reset rx fail: rx queue index: %d err:
%d\n", qindex, err);
+
+		pool = NULL;
+	}
+
+	if (!pool)
+		xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
+
+	rq->xsk.pool = pool;
+
+	virtnet_rx_resume(vi, rq);
+
+	return err;
+}
+
+static int virtnet_sq_bind_xsk_pool(struct virtnet_info *vi,
+				    struct virtnet_sq *sq,
+				    struct xsk_buff_pool *pool)
+{
+	int err, qindex;
+
+	qindex = sq - vi->sq;
+
+	virtnet_tx_pause(vi, sq);
+
+	err = virtqueue_reset(sq->vq, virtnet_sq_free_unused_buf);
+	if (err) {
+		pool = NULL;
+		netdev_err(vi->dev, "reset tx fail: tx queue index: %d err:
%d\n", qindex, err);
+	}
+
+	sq->xsk.pool = pool;
+
+	virtnet_tx_resume(vi, sq);
+
+	return err;
+}
+
+static int virtnet_xsk_pool_enable(struct net_device *dev,
+				   struct xsk_buff_pool *pool,
+				   u16 qid)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	struct virtnet_rq *rq;
+	struct virtnet_sq *sq;
+	struct device *dma_dev;
+	dma_addr_t hdr_dma;
+	int err;
+
+	/* In big_packets mode, xdp cannot work, so there is no need to
+	 * initialize xsk of rq.
+	 */
+	if (vi->big_packets && !vi->mergeable_rx_bufs)
+		return -ENOENT;
+
+	if (qid >= vi->curr_queue_pairs)
+		return -EINVAL;
+
+	sq = &vi->sq[qid];
+	rq = &vi->rq[qid];
+
+	/* xsk tx zerocopy depend on the tx napi.
+	 *
+	 * All xsk packets are actually consumed and sent out from the xsk tx
+	 * queue under the tx napi mechanism.
+	 */
+	if (!sq->napi.weight)
+		return -EPERM;
+
+	if (!rq->do_dma || !sq->do_dma)
+		return -EPERM;
+
+	/* For the xsk, the tx and rx should have the same device. But
+	 * vq->dma_dev allows every vq has the respective dma dev. So I check
+	 * the dma dev of vq and sq is the same dev.
+	 */
+	if (virtqueue_dma_dev(rq->vq) != virtqueue_dma_dev(sq->vq))
+		return -EPERM;
+
+	dma_dev = virtqueue_dma_dev(rq->vq);
+	if (!dma_dev)
+		return -EPERM;
+
+	hdr_dma = dma_map_single(dma_dev, &xsk_hdr, vi->hdr_len,
DMA_TO_DEVICE);
+	if (dma_mapping_error(dma_dev, hdr_dma))
+		return -ENOMEM;
+
+	err = xsk_pool_dma_map(pool, dma_dev, 0);
+	if (err)
+		goto err_xsk_map;
+
+	err = virtnet_rq_bind_xsk_pool(vi, rq, pool);
+	if (err)
+		goto err_rq;
+
+	err = virtnet_sq_bind_xsk_pool(vi, sq, pool);
+	if (err)
+		goto err_sq;
+
+	/* Now, we do not support tx offset, so all the tx virtnet hdr is zero.
+	 * So all the tx packets can share a single hdr.
+	 */
+	sq->xsk.hdr_dma_address = hdr_dma;
+
+	return 0;
+
+err_sq:
+	virtnet_rq_bind_xsk_pool(vi, rq, NULL);
+err_rq:
+	xsk_pool_dma_unmap(pool, 0);
+err_xsk_map:
+	dma_unmap_single(dma_dev, hdr_dma, vi->hdr_len, DMA_TO_DEVICE);
+	return err;
+}
+
+static int virtnet_xsk_pool_disable(struct net_device *dev, u16 qid)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	struct xsk_buff_pool *pool;
+	struct device *dma_dev;
+	struct virtnet_rq *rq;
+	struct virtnet_sq *sq;
+	int err1, err2;
+
+	if (qid >= vi->curr_queue_pairs)
+		return -EINVAL;
+
+	sq = &vi->sq[qid];
+	rq = &vi->rq[qid];
+
+	pool = sq->xsk.pool;
+
+	err1 = virtnet_sq_bind_xsk_pool(vi, sq, NULL);
+	err2 = virtnet_rq_bind_xsk_pool(vi, rq, NULL);
+
+	xsk_pool_dma_unmap(pool, 0);
+
+	dma_dev = virtqueue_dma_dev(rq->vq);
+
+	dma_unmap_single(dma_dev, sq->xsk.hdr_dma_address, vi->hdr_len,
DMA_TO_DEVICE);
+
+	return err1 | err2;
+}
+
+int virtnet_xsk_pool_setup(struct net_device *dev, struct netdev_bpf *xdp)
+{
+	if (xdp->xsk.pool)
+		return virtnet_xsk_pool_enable(dev, xdp->xsk.pool,
+					       xdp->xsk.queue_id);
+	else
+		return virtnet_xsk_pool_disable(dev, xdp->xsk.queue_id);
+}
diff --git a/drivers/net/virtio/xsk.h b/drivers/net/virtio/xsk.h
new file mode 100644
index 000000000000..1918285c310c
--- /dev/null
+++ b/drivers/net/virtio/xsk.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef __XSK_H__
+#define __XSK_H__
+
+int virtnet_xsk_pool_setup(struct net_device *dev, struct netdev_bpf *xdp);
+#endif
--
2.32.0.3.g01195cf9f