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[PATCH v2 2/4] hw/net/virtio-net: Adapt hash handling to updated UAPI

Shameer Kolothum posted 4 patches 3 weeks, 5 days ago
There is a newer version of this series
[PATCH v2 2/4] hw/net/virtio-net: Adapt hash handling to updated UAPI
Posted by Shameer Kolothum 3 weeks, 5 days ago 
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 <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>
---
 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
Re: [PATCH v2 2/4] hw/net/virtio-net: Adapt hash handling to updated UAPI
Posted by Michael S. Tsirkin 5 days, 15 hours ago 
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 <mst@redhat.com>
> Cc: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>


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
Re: [PATCH v2 2/4] hw/net/virtio-net: Adapt hash handling to updated UAPI
Posted by Cédric Le Goater 3 weeks, 3 days ago 
On 1/13/26 12:37, 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 <mst@redhat.com>
> Cc: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>
> ---
>   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;

Reviewed-by: Cédric Le Goater <clg@redhat.com>

Thanks,

C.

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