On Tue, Feb 27, 2024 at 04:03:00PM +0800, Xuan Zhuo wrote:

As the spec https://github.com/oasis-tcs/virtio-spec/commit/42f389989823039724f95bbbd243291ab0064f82

make virtio-net support getting the stats from the device by ethtool -S
<eth0>.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>

...

+static int virtnet_get_hw_stats(struct virtnet_info *vi,
+				struct virtnet_stats_ctx *ctx)
+{
+	struct virtio_net_ctrl_queue_stats *req;
+	struct virtio_net_stats_reply_hdr *hdr;
+	struct scatterlist sgs_in, sgs_out;
+	u32 num_rx, num_tx, num_cq, offset;
+	int qnum, i, j,  qid, res_size;
+	struct virtnet_stats_map *m;
+	void *reply, *p;
+	u64 bitmap;
+	int ok;
+	u64 *v;
+
+	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_DEVICE_STATS))
+		return 0;
+
+	qnum = 0;
+	if (ctx->bitmap_cq)
+		qnum += 1;
+
+	if (ctx->bitmap_rx)
+		qnum += vi->curr_queue_pairs;
+
+	if (ctx->bitmap_tx)
+		qnum += vi->curr_queue_pairs;
+
+	req = kcalloc(qnum, sizeof(*req), GFP_KERNEL);
+	if (!req)
+		return -ENOMEM;
+
+	res_size = (ctx->size_rx + ctx->size_tx) * vi->curr_queue_pairs + ctx->size_cq;
+	reply = kmalloc(res_size, GFP_KERNEL);
+	if (!reply) {
+		kfree(req);
+		return -ENOMEM;
+	}
+
+	j = 0;
+	for (i = 0; i < vi->curr_queue_pairs; ++i) {
+		if (ctx->bitmap_rx) {
+			req->stats[j].vq_index = cpu_to_le16(i * 2);
+			req->stats[j].types_bitmap[0] = cpu_to_le64(ctx->bitmap_rx);
+			++j;
+		}
+
+		if (ctx->bitmap_tx) {
+			req->stats[j].vq_index = cpu_to_le16(i * 2 + 1);
+			req->stats[j].types_bitmap[0] = cpu_to_le64(ctx->bitmap_tx);
+			++j;
+		}
+	}
+
+	if (ctx->size_cq) {
+		req->stats[j].vq_index = cpu_to_le16(vi->max_queue_pairs * 2);
+		req->stats[j].types_bitmap[0] = cpu_to_le64(ctx->bitmap_cq);
+		++j;
+	}
+
+	sg_init_one(&sgs_out, req, sizeof(*req) * j);
+	sg_init_one(&sgs_in, reply, res_size);
+
+	ok = virtnet_send_command(vi, VIRTIO_NET_CTRL_STATS,
+				  VIRTIO_NET_CTRL_STATS_GET,
+				  &sgs_out, &sgs_in);
+	kfree(req);
+
+	if (!ok) {
+		kfree(reply);
+		return ok;
+	}
+
+	num_rx = VIRTNET_RQ_STATS_LEN + ctx->num_rx;
+	num_tx = VIRTNET_SQ_STATS_LEN + ctx->num_tx;
+	num_cq = ctx->num_tx;
+
+	for (p = reply; p - reply < res_size; p += le16_to_cpu(hdr->size)) {
+		hdr = p;
+
+		qid = le16_to_cpu(hdr->vq_index);
+
+		if (qid == vi->max_queue_pairs * 2) {
+			offset = 0;
+			bitmap = ctx->bitmap_cq;
+		} else if (qid % 2) {
+			offset = num_cq + num_rx * vi->curr_queue_pairs + num_tx * (qid / 2);
+			offset += VIRTNET_SQ_STATS_LEN;
+			bitmap = ctx->bitmap_tx;
+		} else {
+			offset = num_cq + num_rx * (qid / 2) + VIRTNET_RQ_STATS_LEN;
+			bitmap = ctx->bitmap_rx;
+		}
+
+		for (i = 0; i < ARRAY_SIZE(virtio_net_stats_map); ++i) {
+			m = &virtio_net_stats_map[i];
+
+			if (m->stat_type & bitmap)
+				offset += m->num;
+
+			if (hdr->type != m->reply_type)
+				continue;
+
+			for (j = 0; j < m->num; ++j) {
+				v = p + m->desc[j].offset;
+				ctx->data[offset + j] = le64_to_cpu(*v);

Hi Xuan Zhuo,

Sparse complains about the line above because the type of *v is u64,
but le64_to_cpu() expects __le64.

+			}
+
+			break;
+		}
+	}
+
+	kfree(reply);
+	return 0;
+}
+
 static void virtnet_get_strings(struct net_device *dev, u32 stringset, u8 *data)
 {
 	struct virtnet_info *vi = netdev_priv(dev);

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