Merge branch 'virtio_net-fixes-and-improvements'

Akihiko Odaki says:

====================
virtio_net: Fixes and improvements

Jason Wang recently proposed an improvement to struct
virtio_net_rss_config:
https://lore.kernel.org/CACGkMEud0Ki8p=z299Q7b4qEDONpYDzbVqhHxCNVk_vo-KdP9A@mail.gmail.com

This patch series implements it and also fixes a few minor bugs I found
when writing patches.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>

v1: https://lore.kernel.org/20250318-virtio-v1-0-344caf336ddd@daynix.com
====================

Link: https://patch.msgid.link/20250321-virtio-v2-0-33afb8f4640b@daynix.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/virtio_net.c

@@ -360,24 +360,7 @@ struct receive_queue {
 	struct xdp_buff **xsk_buffs;
 };
 
-/* This structure can contain rss message with maximum settings for indirection table and keysize
- * Note, that default structure that describes RSS configuration virtio_net_rss_config
- * contains same info but can't handle table values.
- * In any case, structure would be passed to virtio hw through sg_buf split by parts
- * because table sizes may be differ according to the device configuration.
- */
 #define VIRTIO_NET_RSS_MAX_KEY_SIZE     40
-struct virtio_net_ctrl_rss {
-	u32 hash_types;
-	u16 indirection_table_mask;
-	u16 unclassified_queue;
-	u16 hash_cfg_reserved; /* for HASH_CONFIG (see virtio_net_hash_config for details) */
-	u16 max_tx_vq;
-	u8 hash_key_length;
-	u8 key[VIRTIO_NET_RSS_MAX_KEY_SIZE];
-
-	u16 *indirection_table;
-};
 
 /* Control VQ buffers: protected by the rtnl lock */
 struct control_buf {
@@ -421,7 +404,9 @@ struct virtnet_info {
 	u16 rss_indir_table_size;
 	u32 rss_hash_types_supported;
 	u32 rss_hash_types_saved;
-	struct virtio_net_ctrl_rss rss;
+	struct virtio_net_rss_config_hdr *rss_hdr;
+	struct virtio_net_rss_config_trailer rss_trailer;
+	u8 rss_hash_key_data[VIRTIO_NET_RSS_MAX_KEY_SIZE];
 
 	/* Has control virtqueue */
 	bool has_cvq;
@@ -523,23 +508,16 @@ enum virtnet_xmit_type {
 	VIRTNET_XMIT_TYPE_XSK,
 };
 
-static int rss_indirection_table_alloc(struct virtio_net_ctrl_rss *rss, u16 indir_table_size)
+static size_t virtnet_rss_hdr_size(const struct virtnet_info *vi)
 {
-	if (!indir_table_size) {
-		rss->indirection_table = NULL;
-		return 0;
-	}
+	u16 indir_table_size = vi->has_rss ? vi->rss_indir_table_size : 1;
 
-	rss->indirection_table = kmalloc_array(indir_table_size, sizeof(u16), GFP_KERNEL);
-	if (!rss->indirection_table)
-		return -ENOMEM;
-
-	return 0;
+	return struct_size(vi->rss_hdr, indirection_table, indir_table_size);
 }
 
-static void rss_indirection_table_free(struct virtio_net_ctrl_rss *rss)
+static size_t virtnet_rss_trailer_size(const struct virtnet_info *vi)
 {
-	kfree(rss->indirection_table);
+	return struct_size(&vi->rss_trailer, hash_key_data, vi->rss_key_size);
 }
 
 /* We use the last two bits of the pointer to distinguish the xmit type. */
@@ -3638,15 +3616,16 @@ static void virtnet_rss_update_by_qpairs(struct virtnet_info *vi, u16 queue_pair
 
 	for (; i < vi->rss_indir_table_size; ++i) {
 		indir_val = ethtool_rxfh_indir_default(i, queue_pairs);
-		vi->rss.indirection_table[i] = indir_val;
+		vi->rss_hdr->indirection_table[i] = cpu_to_le16(indir_val);
 	}
-	vi->rss.max_tx_vq = queue_pairs;
+	vi->rss_trailer.max_tx_vq = cpu_to_le16(queue_pairs);
 }
 
 static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
 {
 	struct virtio_net_ctrl_mq *mq __free(kfree) = NULL;
-	struct virtio_net_ctrl_rss old_rss;
+	struct virtio_net_rss_config_hdr *old_rss_hdr;
+	struct virtio_net_rss_config_trailer old_rss_trailer;
 	struct net_device *dev = vi->dev;
 	struct scatterlist sg;
 
@@ -3661,24 +3640,28 @@ static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
 	 * update (VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET below) and return directly.
 	 */
 	if (vi->has_rss && !netif_is_rxfh_configured(dev)) {
-		memcpy(&old_rss, &vi->rss, sizeof(old_rss));
-		if (rss_indirection_table_alloc(&vi->rss, vi->rss_indir_table_size)) {
-			vi->rss.indirection_table = old_rss.indirection_table;
+		old_rss_hdr = vi->rss_hdr;
+		old_rss_trailer = vi->rss_trailer;
+		vi->rss_hdr = devm_kzalloc(&dev->dev, virtnet_rss_hdr_size(vi), GFP_KERNEL);
+		if (!vi->rss_hdr) {
+			vi->rss_hdr = old_rss_hdr;
 			return -ENOMEM;
 		}
 
+		*vi->rss_hdr = *old_rss_hdr;
 		virtnet_rss_update_by_qpairs(vi, queue_pairs);
 
 		if (!virtnet_commit_rss_command(vi)) {
 			/* restore ctrl_rss if commit_rss_command failed */
-			rss_indirection_table_free(&vi->rss);
-			memcpy(&vi->rss, &old_rss, sizeof(old_rss));
+			devm_kfree(&dev->dev, vi->rss_hdr);
+			vi->rss_hdr = old_rss_hdr;
+			vi->rss_trailer = old_rss_trailer;
 
 			dev_warn(&dev->dev, "Fail to set num of queue pairs to %d, because committing RSS failed\n",
 				 queue_pairs);
 			return -EINVAL;
 		}
-		rss_indirection_table_free(&old_rss);
+		devm_kfree(&dev->dev, old_rss_hdr);
 		goto succ;
 	}
 
@@ -4121,28 +4104,12 @@ static int virtnet_set_ringparam(struct net_device *dev,
 static bool virtnet_commit_rss_command(struct virtnet_info *vi)
 {
 	struct net_device *dev = vi->dev;
-	struct scatterlist sgs[4];
-	unsigned int sg_buf_size;
+	struct scatterlist sgs[2];
 
 	/* prepare sgs */
-	sg_init_table(sgs, 4);
-
-	sg_buf_size = offsetof(struct virtio_net_ctrl_rss, hash_cfg_reserved);
-	sg_set_buf(&sgs[0], &vi->rss, sg_buf_size);
-
-	if (vi->has_rss) {
-		sg_buf_size = sizeof(uint16_t) * vi->rss_indir_table_size;
-		sg_set_buf(&sgs[1], vi->rss.indirection_table, sg_buf_size);
-	} else {
-		sg_set_buf(&sgs[1], &vi->rss.hash_cfg_reserved, sizeof(uint16_t));
-	}
-
-	sg_buf_size = offsetof(struct virtio_net_ctrl_rss, key)
-			- offsetof(struct virtio_net_ctrl_rss, max_tx_vq);
-	sg_set_buf(&sgs[2], &vi->rss.max_tx_vq, sg_buf_size);
-
-	sg_buf_size = vi->rss_key_size;
-	sg_set_buf(&sgs[3], vi->rss.key, sg_buf_size);
+	sg_init_table(sgs, 2);
+	sg_set_buf(&sgs[0], vi->rss_hdr, virtnet_rss_hdr_size(vi));
+	sg_set_buf(&sgs[1], &vi->rss_trailer, virtnet_rss_trailer_size(vi));
 
 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
 				  vi->has_rss ? VIRTIO_NET_CTRL_MQ_RSS_CONFIG
@@ -4159,17 +4126,17 @@ static bool virtnet_commit_rss_command(struct virtnet_info *vi)
 
 static void virtnet_init_default_rss(struct virtnet_info *vi)
 {
-	vi->rss.hash_types = vi->rss_hash_types_supported;
+	vi->rss_hdr->hash_types = cpu_to_le32(vi->rss_hash_types_supported);
 	vi->rss_hash_types_saved = vi->rss_hash_types_supported;
-	vi->rss.indirection_table_mask = vi->rss_indir_table_size
-						? vi->rss_indir_table_size - 1 : 0;
-	vi->rss.unclassified_queue = 0;
+	vi->rss_hdr->indirection_table_mask = vi->rss_indir_table_size
+						? cpu_to_le16(vi->rss_indir_table_size - 1) : 0;
+	vi->rss_hdr->unclassified_queue = 0;
 
 	virtnet_rss_update_by_qpairs(vi, vi->curr_queue_pairs);
 
-	vi->rss.hash_key_length = vi->rss_key_size;
+	vi->rss_trailer.hash_key_length = vi->rss_key_size;
 
-	netdev_rss_key_fill(vi->rss.key, vi->rss_key_size);
+	netdev_rss_key_fill(vi->rss_hash_key_data, vi->rss_key_size);
 }
 
 static void virtnet_get_hashflow(const struct virtnet_info *vi, struct ethtool_rxnfc *info)
@@ -4280,7 +4247,7 @@ static bool virtnet_set_hashflow(struct virtnet_info *vi, struct ethtool_rxnfc *
 
 	if (new_hashtypes != vi->rss_hash_types_saved) {
 		vi->rss_hash_types_saved = new_hashtypes;
-		vi->rss.hash_types = vi->rss_hash_types_saved;
+		vi->rss_hdr->hash_types = cpu_to_le32(vi->rss_hash_types_saved);
 		if (vi->dev->features & NETIF_F_RXHASH)
 			return virtnet_commit_rss_command(vi);
 	}
@@ -5460,11 +5427,11 @@ static int virtnet_get_rxfh(struct net_device *dev,
 
 	if (rxfh->indir) {
 		for (i = 0; i < vi->rss_indir_table_size; ++i)
-			rxfh->indir[i] = vi->rss.indirection_table[i];
+			rxfh->indir[i] = le16_to_cpu(vi->rss_hdr->indirection_table[i]);
 	}
 
 	if (rxfh->key)
-		memcpy(rxfh->key, vi->rss.key, vi->rss_key_size);
+		memcpy(rxfh->key, vi->rss_hash_key_data, vi->rss_key_size);
 
 	rxfh->hfunc = ETH_RSS_HASH_TOP;
 
@@ -5488,7 +5455,7 @@ static int virtnet_set_rxfh(struct net_device *dev,
 			return -EOPNOTSUPP;
 
 		for (i = 0; i < vi->rss_indir_table_size; ++i)
-			vi->rss.indirection_table[i] = rxfh->indir[i];
+			vi->rss_hdr->indirection_table[i] = cpu_to_le16(rxfh->indir[i]);
 		update = true;
 	}
 
@@ -5500,7 +5467,7 @@ static int virtnet_set_rxfh(struct net_device *dev,
 		if (!vi->has_rss && !vi->has_rss_hash_report)
 			return -EOPNOTSUPP;
 
-		memcpy(vi->rss.key, rxfh->key, vi->rss_key_size);
+		memcpy(vi->rss_hash_key_data, rxfh->key, vi->rss_key_size);
 		update = true;
 	}
 
@@ -6109,9 +6076,9 @@ static int virtnet_set_features(struct net_device *dev,
 
 	if ((dev->features ^ features) & NETIF_F_RXHASH) {
 		if (features & NETIF_F_RXHASH)
-			vi->rss.hash_types = vi->rss_hash_types_saved;
+			vi->rss_hdr->hash_types = cpu_to_le32(vi->rss_hash_types_saved);
 		else
-			vi->rss.hash_types = VIRTIO_NET_HASH_REPORT_NONE;
+			vi->rss_hdr->hash_types = cpu_to_le32(VIRTIO_NET_HASH_REPORT_NONE);
 
 		if (!virtnet_commit_rss_command(vi))
 			return -EINVAL;
@@ -6801,9 +6768,11 @@ static int virtnet_probe(struct virtio_device *vdev)
 			virtio_cread16(vdev, offsetof(struct virtio_net_config,
 				rss_max_indirection_table_length));
 	}
-	err = rss_indirection_table_alloc(&vi->rss, vi->rss_indir_table_size);
-	if (err)
+	vi->rss_hdr = devm_kzalloc(&vdev->dev, virtnet_rss_hdr_size(vi), GFP_KERNEL);
+	if (!vi->rss_hdr) {
+		err = -ENOMEM;
 		goto free;
+	}
 
 	if (vi->has_rss || vi->has_rss_hash_report) {
 		vi->rss_key_size =
@@ -7082,8 +7051,6 @@ static void virtnet_remove(struct virtio_device *vdev)
 
 	remove_vq_common(vi);
 
-	rss_indirection_table_free(&vi->rss);
-
 	free_netdev(vi->dev);
 }
 

include/uapi/linux/virtio_net.h

@@ -327,6 +327,19 @@ struct virtio_net_rss_config {
 	__u8 hash_key_data[/* hash_key_length */];
 };
 
+struct virtio_net_rss_config_hdr {
+	__le32 hash_types;
+	__le16 indirection_table_mask;
+	__le16 unclassified_queue;
+	__le16 indirection_table[/* 1 + indirection_table_mask */];
+};
+
+struct virtio_net_rss_config_trailer {
+	__le16 max_tx_vq;
+	__u8 hash_key_length;
+	__u8 hash_key_data[/* hash_key_length */];
+};
+
  #define VIRTIO_NET_CTRL_MQ_RSS_CONFIG          1
 
 /*