virtio_net: Support dynamic rss indirection table size

When reading/writing virtio_net_ctrl_rss, we get the indirection table
size from vi->rss_indir_table_size, which is initialized in
virtnet_probe(). However, the actual size of indirection_table was set
as VIRTIO_NET_RSS_MAX_TABLE_LEN=128. This collision may cause issues if
the vi->rss_indir_table_size exceeds 128.

This patch instead uses dynamic indirection table, allocated with
vi->rss after vi->rss_indir_table_size initialized. And free it in
virtnet_remove().

In virtnet_commit_rss_command(), sgs for rss is initialized differently
with hash_report. So indirection_table is not used if !vi->has_rss, and
then we don't need to alloc indirection_table for hash_report only uses.

Fixes: c7114b1249fa ("drivers/net/virtio_net: Added basic RSS support.")
Signed-off-by: Philo Lu <lulie@linux.alibaba.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Joe Damato <jdamato@fastly.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 792e9eadbfc3dce4bc146b7b799d602dd32f7f82..4b507007d242b82ad79bc3dce7955350c8e79b6e 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -368,15 +368,16 @@ struct receive_queue {
  * because table sizes may be differ according to the device configuration.
  */
 #define VIRTIO_NET_RSS_MAX_KEY_SIZE     40
-#define VIRTIO_NET_RSS_MAX_TABLE_LEN    128
 struct virtio_net_ctrl_rss {
        u32 hash_types;
        u16 indirection_table_mask;
        u16 unclassified_queue;
-       u16 indirection_table[VIRTIO_NET_RSS_MAX_TABLE_LEN];
+       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 */
@@ -512,6 +513,25 @@ static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
                                               struct page *page, void *buf,
                                               int len, int truesize);
 
+static int rss_indirection_table_alloc(struct virtio_net_ctrl_rss *rss, u16 indir_table_size)
+{
+       if (!indir_table_size) {
+               rss->indirection_table = NULL;
+               return 0;
+       }
+
+       rss->indirection_table = kmalloc_array(indir_table_size, sizeof(u16), GFP_KERNEL);
+       if (!rss->indirection_table)
+               return -ENOMEM;
+
+       return 0;
+}
+
+static void rss_indirection_table_free(struct virtio_net_ctrl_rss *rss)
+{
+       kfree(rss->indirection_table);
+}
+
 static bool is_xdp_frame(void *ptr)
 {
        return (unsigned long)ptr & VIRTIO_XDP_FLAG;
@@ -3828,11 +3848,15 @@ static bool virtnet_commit_rss_command(struct virtnet_info *vi)
        /* prepare sgs */
        sg_init_table(sgs, 4);
 
-       sg_buf_size = offsetof(struct virtio_net_ctrl_rss, indirection_table);
+       sg_buf_size = offsetof(struct virtio_net_ctrl_rss, hash_cfg_reserved);
        sg_set_buf(&sgs[0], &vi->rss, sg_buf_size);
 
-       sg_buf_size = sizeof(uint16_t) * (vi->rss.indirection_table_mask + 1);
-       sg_set_buf(&sgs[1], vi->rss.indirection_table, 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);
@@ -6420,6 +6444,9 @@ 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)
+               goto free;
 
        if (vi->has_rss || vi->has_rss_hash_report) {
                vi->rss_key_size =
@@ -6674,6 +6701,8 @@ static void virtnet_remove(struct virtio_device *vdev)
 
        remove_vq_common(vi);
 
+       rss_indirection_table_free(&vi->rss);
+
        free_netdev(vi->dev);
 }