On Tue, Jan 13, 2026 at 11:37:52AM +0000, Shameer Kolothum wrote:
> The virtio_net_hdr_v1_hash layout changed in the Linux UAPI, replacing
> the 32-bit hash_value field with two 16-bit fields, hash_value_lo and
> hash_value_hi.
>
> Update hash handling to populate the new fields correctly and adjust
> offset and size calculations accordingly.
>
> Cc: Michael S. Tsirkin <[email protected]>
> Cc: Jason Wang <[email protected]>
> Signed-off-by: Shameer Kolothum <[email protected]>
Has to be squashed in patch 1 or bisect will be broken.
> ---
> hw/net/virtio-net.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 317f1ad23b..512a7c02c9 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -1879,7 +1879,8 @@ static int virtio_net_process_rss(NetClientState *nc,
> const uint8_t *buf,
> n->rss_data.runtime_hash_types);
> if (net_hash_type > NetPktRssIpV6UdpEx) {
> if (n->rss_data.populate_hash) {
> - hdr->hash_value = VIRTIO_NET_HASH_REPORT_NONE;
> + hdr->hash_value_lo = VIRTIO_NET_HASH_REPORT_NONE;
> + hdr->hash_value_hi = VIRTIO_NET_HASH_REPORT_NONE;
> hdr->hash_report = 0;
> }
> return n->rss_data.redirect ? n->rss_data.default_queue : -1;
> @@ -1888,7 +1889,8 @@ static int virtio_net_process_rss(NetClientState *nc,
> const uint8_t *buf,
> hash = net_rx_pkt_calc_rss_hash(pkt, net_hash_type, n->rss_data.key);
>
> if (n->rss_data.populate_hash) {
> - hdr->hash_value = hash;
> + hdr->hash_value_lo = cpu_to_le16(hash & 0xffff);
> + hdr->hash_value_hi = cpu_to_le16((hash >> 16) & 0xffff);
> hdr->hash_report = reports[net_hash_type];
> }
>
> @@ -1990,10 +1992,11 @@ static ssize_t virtio_net_receive_rcu(NetClientState
> *nc, const uint8_t *buf,
>
> receive_header(n, sg, elem->in_num, buf, size);
> if (n->rss_data.populate_hash) {
> - offset = offsetof(typeof(extra_hdr), hash_value);
> + offset = offsetof(typeof(extra_hdr), hash_value_lo);
> iov_from_buf(sg, elem->in_num, offset,
> (char *)&extra_hdr + offset,
> - sizeof(extra_hdr.hash_value) +
> + sizeof(extra_hdr.hash_value_lo) +
> + sizeof(extra_hdr.hash_value_hi) +
> sizeof(extra_hdr.hash_report));
> }
> offset = n->host_hdr_len;
> --
> 2.43.0
