Re: [PATCH net-next v9 6/6] vhost/net: Support VIRTIO_NET_F_HASH_REPORT

On Fri, Mar 7, 2025 at 7:02 PM Akihiko Odaki akihiko.odaki@daynix.com wrote:

VIRTIO_NET_F_HASH_REPORT allows to report hash values calculated on the host. When VHOST_NET_F_VIRTIO_NET_HDR is employed, it will report no hash values (i.e., the hash_report member is always set to VIRTIO_NET_HASH_REPORT_NONE). Otherwise, the values reported by the underlying socket will be reported.

VIRTIO_NET_F_HASH_REPORT requires VIRTIO_F_VERSION_1.

Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com Tested-by: Lei Yang leiyang@redhat.com

---

drivers/vhost/net.c | 49 +++++++++++++++++++++++++++++-------------------- 1 file changed, 29 insertions(+), 20 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index b9b9e9d40951856d881d77ac74331d914473cd56..16b241b44f89820a42c302f3586ea6bb5e0d4289 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -73,6 +73,7 @@ enum { VHOST_NET_FEATURES = VHOST_FEATURES | (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | (1ULL << VIRTIO_NET_F_MRG_RXBUF) |

•                    (1ULL << VIRTIO_NET_F_HASH_REPORT) |
                     (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
                     (1ULL << VIRTIO_F_RING_RESET)
  

}; @@ -1097,9 +1098,11 @@ static void handle_rx(struct vhost_net *net) .msg_controllen = 0, .msg_flags = MSG_DONTWAIT, };

•   struct virtio_net_hdr hdr = {
  

•           .flags = 0,
  

•           .gso_type = VIRTIO_NET_HDR_GSO_NONE
  

•   struct virtio_net_hdr_v1_hash hdr = {
  

•           .hdr = {
  

•                   .flags = 0,
  

•                   .gso_type = VIRTIO_NET_HDR_GSO_NONE
  

•           }
    };
    size_t total_len = 0;
    int err, mergeable;
  

@@ -1110,7 +1113,6 @@ static void handle_rx(struct vhost_net *net) bool set_num_buffers; struct socket *sock; struct iov_iter fixup;

•   __virtio16 num_buffers;
    int recv_pkts = 0;
  
    mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX);
  

@@ -1191,30 +1193,30 @@ static void handle_rx(struct vhost_net *net) vhost_discard_vq_desc(vq, headcount); continue; }

•           hdr.hdr.num_buffers = cpu_to_vhost16(vq, headcount);
            /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
            if (unlikely(vhost_hlen)) {
  

•                   if (copy_to_iter(&hdr, sizeof(hdr),
  

•                                    &fixup) != sizeof(hdr)) {
  

•                   if (copy_to_iter(&hdr, vhost_hlen,
  

•                                    &fixup) != vhost_hlen) {
                            vq_err(vq, "Unable to write vnet_hdr "
                                   "at addr %p\n", vq->iov->iov_base);
                            goto out;
  

Is this an "issue" specific to RSS/HASH? If it's not, we need a separate patch.

Honestly, I'm not sure if it's too late to fix this.

Others look fine.

Thanks