Hi Chenbo,
> -----Original Message-----
> From: Xia, Chenbo <chenbo....@intel.com>
> Sent: Thursday, July 15, 2021 4:37 PM
> To: Jiang, Cheng1 <cheng1.ji...@intel.com>; maxime.coque...@redhat.com
> Cc: dev@dpdk.org; Hu, Jiayu <jiayu...@intel.com>; Yang, YvonneX
> <yvonnex.y...@intel.com>; sta...@dpdk.org
> Subject: RE: [PATCH] vhost: fix index overflow issue in async vhost
>
> Hi Cheng,
>
> > -----Original Message-----
> > From: Jiang, Cheng1 <cheng1.ji...@intel.com>
> > Sent: Thursday, July 8, 2021 6:45 PM
> > To: maxime.coque...@redhat.com; Xia, Chenbo <chenbo....@intel.com>
> > Cc: dev@dpdk.org; Hu, Jiayu <jiayu...@intel.com>; Yang, YvonneX
> > <yvonnex.y...@intel.com>; Jiang, Cheng1 <cheng1.ji...@intel.com>;
> > sta...@dpdk.org
> > Subject: [PATCH] vhost: fix index overflow issue in async vhost
>
> Since this fix is packed ring only, maybe 'fix index overflow for packed ring
> in
> async vhost' is better.
>
Sure, that make sense.
I'll fix it in the next version.
> >
> > We introduced some new indexes in async vhost. If we don't pay
> > attention to the management of these indexes, they will eventually
> > overflow and lead to errors. This patch is to check and keep these
> > indexes within a reasonable range.
>
> Ditto. Should mention packed ring here.
Sure.
>
> >
> > Fixes: 873e8dad6f49 ("vhost: support packed ring in async datapath")
> > Cc: sta...@dpdk.org
> >
> > Signed-off-by: Cheng Jiang <cheng1.ji...@intel.com>
> > ---
> > lib/vhost/virtio_net.c | 22 +++++++++++++++-------
> > 1 file changed, 15 insertions(+), 7 deletions(-)
> >
> > diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c index
> > f4a2c88d8b..61cb5a126c 100644
> > --- a/lib/vhost/virtio_net.c
> > +++ b/lib/vhost/virtio_net.c
> > @@ -1614,6 +1614,7 @@ store_dma_desc_info_packed(struct
> > vring_used_elem_packed *s_ring,
> >
> > if (d_idx + count <= ring_size) {
> > rte_memcpy(d_ring + d_idx, s_ring + s_idx, count *
> elem_size);
> > +
>
Maybe it's a typo. I'll fix it.
Thanks,
Cheng
> Do we need a blank line here?
>
> Thanks,
> Chenbo
>
> > } else {
> > uint16_t size = ring_size - d_idx;
> >
> > @@ -2036,7 +2037,7 @@ virtio_dev_rx_async_submit_packed(struct
> > virtio_net *dev,
> >
> > slot_idx = (vq->async_pkts_idx + num_async_pkts) % vq-
> >size;
> > if (it_pool[it_idx].count) {
> > - uint16_t from, to;
> > + uint16_t from;
> >
> > async_descs_idx += num_descs;
> > async_fill_desc(&tdes[pkt_burst_idx++],
> > @@ -2055,11 +2056,13 @@ virtio_dev_rx_async_submit_packed(struct
> > virtio_net *dev,
> > * descriptors.
> > */
> > from = vq->shadow_used_idx - num_buffers;
> > - to = vq->async_buffer_idx_packed % vq->size;
> > store_dma_desc_info_packed(vq-
> >shadow_used_packed,
> > - vq->async_buffers_packed, vq->size,
> from, to,
> > num_buffers);
> > + vq->async_buffers_packed, vq->size,
> from,
> > + vq->async_buffer_idx_packed,
> num_buffers);
> >
> > vq->async_buffer_idx_packed += num_buffers;
> > + if (vq->async_buffer_idx_packed >= vq->size)
> > + vq->async_buffer_idx_packed -= vq->size;
> > vq->shadow_used_idx -= num_buffers;
> > } else {
> > comp_pkts[num_done_pkts++] = pkts[pkt_idx]; @@
> -2112,6 +2115,8 @@
> > virtio_dev_rx_async_submit_packed(struct virtio_net *dev,
> > dma_error_handler_packed(vq, async_descs,
> async_descs_idx,
> > slot_idx, pkt_err,
> > &pkt_idx, &num_async_pkts,
> &num_done_pkts);
> > vq->async_pkts_idx += num_async_pkts;
> > + if (vq->async_pkts_idx >= vq->size)
> > + vq->async_pkts_idx -= vq->size;
> > *comp_count = num_done_pkts;
> >
> > if (likely(vq->shadow_used_idx)) {
> > @@ -2160,7 +2165,7 @@ write_back_completed_descs_packed(struct
> > vhost_virtqueue *vq,
> > uint16_t from, to;
> >
> > do {
> > - from = vq->last_async_buffer_idx_packed % vq->size;
> > + from = vq->last_async_buffer_idx_packed;
> > to = (from + nr_left) % vq->size;
> > if (to > from) {
> > vhost_update_used_packed(vq, vq-
> >async_buffers_packed + from, to -
> > from); @@ -2169,7 +2174,7 @@
> write_back_completed_descs_packed(struct
> > vhost_virtqueue *vq,
> > } else {
> > vhost_update_used_packed(vq, vq-
> >async_buffers_packed + from,
> > vq->size - from);
> > - vq->last_async_buffer_idx_packed += vq->size -
> from;
> > + vq->last_async_buffer_idx_packed = 0;
> > nr_left -= vq->size - from;
> > }
> > } while (nr_left > 0);
> > @@ -2252,10 +2257,13 @@ uint16_t
> rte_vhost_poll_enqueue_completed(int
> > vid, uint16_t queue_id,
> > vhost_vring_call_split(dev, vq);
> > }
> > } else {
> > - if (vq_is_packed(dev))
> > + if (vq_is_packed(dev)) {
> > vq->last_async_buffer_idx_packed += n_buffers;
> > - else
> > + if (vq->last_async_buffer_idx_packed >= vq->size)
> > + vq->last_async_buffer_idx_packed -= vq-
> >size;
> > + } else {
> > vq->last_async_desc_idx_split += n_descs;
> > + }
> > }
> >
> > done:
> > --
> > 2.29.2
