On Wed, Apr 3, 2024 at 2:12 PM Akihiko Odaki <akihiko.od...@daynix.com> wrote:
>
> The peer buffer is qualified with const and not meant to be modified.
IMHO, this buffer is not so 'const' (although the prototype states so),
it is allocated in net.c
btw, another procedure in this file also modifies the buffer
(work_around_broken_dhclient)
> It also prevents enabling VIRTIO_NET_F_HASH_REPORT for peers without
> virtio-net header support.
Does it mean _this commit_ prevents enabling VIRTIO_NET_F_HASH_REPORT
for peers without
virtio-net header support? Where?
> Signed-off-by: Akihiko Odaki <akihiko.od...@daynix.com>
> ---
> hw/net/virtio-net.c | 36 +++++++++++++++++-------------------
> 1 file changed, 17 insertions(+), 19 deletions(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 2de073ce18fd..ff1884564d0d 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -1823,16 +1823,9 @@ static uint8_t virtio_net_get_hash_type(bool hasip4,
> return 0xff;
> }
>
> -static void virtio_set_packet_hash(const uint8_t *buf, uint8_t report,
> - uint32_t hash)
> -{
> - struct virtio_net_hdr_v1_hash *hdr = (void *)buf;
> - hdr->hash_value = hash;
> - hdr->hash_report = report;
> -}
> -
> static int virtio_net_process_rss(NetClientState *nc, const uint8_t *buf,
> - size_t size)
> + size_t size,
> + struct virtio_net_hdr_v1_hash *hdr)
> {
> VirtIONet *n = qemu_get_nic_opaque(nc);
> unsigned int index = nc->queue_index, new_index = index;
> @@ -1863,7 +1856,8 @@ static int virtio_net_process_rss(NetClientState *nc,
> const uint8_t *buf,
> n->rss_data.hash_types);
> if (net_hash_type > NetPktRssIpV6UdpEx) {
> if (n->rss_data.populate_hash) {
> - virtio_set_packet_hash(buf, VIRTIO_NET_HASH_REPORT_NONE, 0);
> + hdr->hash_value = VIRTIO_NET_HASH_REPORT_NONE;
> + hdr->hash_report = 0;
> }
> return n->rss_data.redirect ? n->rss_data.default_queue : -1;
> }
> @@ -1871,7 +1865,8 @@ 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) {
> - virtio_set_packet_hash(buf, reports[net_hash_type], hash);
> + hdr->hash_value = hash;
> + hdr->hash_report = reports[net_hash_type];
> }
>
> if (n->rss_data.redirect) {
> @@ -1891,7 +1886,7 @@ static ssize_t virtio_net_receive_rcu(NetClientState
> *nc, const uint8_t *buf,
> VirtQueueElement *elems[VIRTQUEUE_MAX_SIZE];
> size_t lens[VIRTQUEUE_MAX_SIZE];
> struct iovec mhdr_sg[VIRTQUEUE_MAX_SIZE];
> - struct virtio_net_hdr_mrg_rxbuf mhdr;
> + struct virtio_net_hdr_v1_hash extra_hdr;
> unsigned mhdr_cnt = 0;
> size_t offset, i, guest_offset, j;
> ssize_t err;
> @@ -1901,7 +1896,7 @@ static ssize_t virtio_net_receive_rcu(NetClientState
> *nc, const uint8_t *buf,
> }
>
> if (!no_rss && n->rss_data.enabled && n->rss_data.enabled_software_rss) {
> - int index = virtio_net_process_rss(nc, buf, size);
> + int index = virtio_net_process_rss(nc, buf, size, &extra_hdr);
> if (index >= 0) {
> NetClientState *nc2 = qemu_get_subqueue(n->nic, index);
> return virtio_net_receive_rcu(nc2, buf, size, true);
> @@ -1961,15 +1956,17 @@ static ssize_t virtio_net_receive_rcu(NetClientState
> *nc, const uint8_t *buf,
> if (n->mergeable_rx_bufs) {
> mhdr_cnt = iov_copy(mhdr_sg, ARRAY_SIZE(mhdr_sg),
> sg, elem->in_num,
> - offsetof(typeof(mhdr), num_buffers),
> - sizeof(mhdr.num_buffers));
> + offsetof(typeof(extra_hdr),
> hdr.num_buffers),
> + sizeof(extra_hdr.hdr.num_buffers));
> }
>
> receive_header(n, sg, elem->in_num, buf, size);
> if (n->rss_data.populate_hash) {
> - offset = sizeof(mhdr);
> + offset = offsetof(typeof(extra_hdr), hash_value);
> iov_from_buf(sg, elem->in_num, offset,
> - buf + offset, n->host_hdr_len - sizeof(mhdr));
> + (char *)&extra_hdr + offset,
> + sizeof(extra_hdr.hash_value) +
> + sizeof(extra_hdr.hash_report));
> }
> offset = n->host_hdr_len;
> total += n->guest_hdr_len;
> @@ -2015,10 +2012,11 @@ static ssize_t virtio_net_receive_rcu(NetClientState
> *nc, const uint8_t *buf,
> }
>
> if (mhdr_cnt) {
> - virtio_stw_p(vdev, &mhdr.num_buffers, i);
> + virtio_stw_p(vdev, &extra_hdr.hdr.num_buffers, i);
> iov_from_buf(mhdr_sg, mhdr_cnt,
> 0,
> - &mhdr.num_buffers, sizeof mhdr.num_buffers);
> + &extra_hdr.hdr.num_buffers,
> + sizeof extra_hdr.hdr.num_buffers);
> }
>
> for (j = 0; j < i; j++) {
>
> --
> 2.44.0
>
