diff mbox series

[v3,3/4] vhost: fix async vector buffer overrun

Message ID 20200929092955.2848419-4-patrick.fu@intel.com (mailing list archive)
State Superseded, archived
Delegated to: Maxime Coquelin
Headers
Series optimize async data path |

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Patrick Fu Sept. 29, 2020, 9:29 a.m. UTC 
  Add check on the async vector buffer usage to prevent the buf overrun.
If the unused vector buffer is not sufficient to prepare for next
packet's iov creation, an async transfer will be triggered immediately
to free the vector buffer.

Fixes: 78639d54563a ("vhost: introduce async enqueue registration API")

Signed-off-by: Patrick Fu <patrick.fu@intel.com>
---
 lib/librte_vhost/vhost.h      |  2 +-
 lib/librte_vhost/virtio_net.c | 13 ++++++++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

Comments

Maxime Coquelin Oct. 5, 2020, 2:19 p.m. UTC | #1 
On 9/29/20 11:29 AM, Patrick Fu wrote:
> Add check on the async vector buffer usage to prevent the buf overrun.
> If the unused vector buffer is not sufficient to prepare for next
> packet's iov creation, an async transfer will be triggered immediately
> to free the vector buffer.
> 
> Fixes: 78639d54563a ("vhost: introduce async enqueue registration API")
> 
> Signed-off-by: Patrick Fu <patrick.fu@intel.com>
> ---
>  lib/librte_vhost/vhost.h      |  2 +-
>  lib/librte_vhost/virtio_net.c | 13 ++++++++++++-
>  2 files changed, 13 insertions(+), 2 deletions(-)

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime
diff mbox series

Patch

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index f0ee00c73..34197ce99 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -47,7 +47,7 @@ 
 #define MAX_PKT_BURST 32
 
 #define VHOST_MAX_ASYNC_IT (MAX_PKT_BURST * 2)
-#define VHOST_MAX_ASYNC_VEC (BUF_VECTOR_MAX * 2)
+#define VHOST_MAX_ASYNC_VEC (BUF_VECTOR_MAX * 4)
 
 #define PACKED_DESC_ENQUEUE_USED_FLAG(w)	\
 	((w) ? (VRING_DESC_F_AVAIL | VRING_DESC_F_USED | VRING_DESC_F_WRITE) : \
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 68ead9a71..60cd5e2b1 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -1492,6 +1492,7 @@  virtio_dev_rx_async_submit_split(struct virtio_net *dev,
 	struct rte_vhost_iov_iter *dst_it = it_pool + 1;
 	uint16_t n_free_slot, slot_idx;
 	uint16_t pkt_err = 0;
+	uint16_t segs_await = 0;
 	struct async_inflight_info *pkts_info = vq->async_pkts_info;
 	int n_pkts = 0;
 
@@ -1540,6 +1541,7 @@  virtio_dev_rx_async_submit_split(struct virtio_net *dev,
 			dst_iovec += dst_it->nr_segs;
 			src_it += 2;
 			dst_it += 2;
+			segs_await += src_it->nr_segs;
 		} else {
 			pkts_info[slot_idx].info = num_buffers;
 			vq->async_pkts_inflight_n++;
@@ -1547,14 +1549,23 @@  virtio_dev_rx_async_submit_split(struct virtio_net *dev,
 
 		vq->last_avail_idx += num_buffers;
 
+		/*
+		 * conditions to trigger async device transfer:
+		 * - buffered packet number reaches transfer threshold
+		 * - this is the last packet in the burst enqueue
+		 * - unused async iov number is less than max vhost vector
+		 */
 		if (pkt_burst_idx >= VHOST_ASYNC_BATCH_THRESHOLD ||
-				(pkt_idx == count - 1 && pkt_burst_idx)) {
+			(pkt_idx == count - 1 && pkt_burst_idx) ||
+			(VHOST_MAX_ASYNC_VEC / 2 - segs_await <
+			BUF_VECTOR_MAX)) {
 			n_pkts = vq->async_ops.transfer_data(dev->vid,
 					queue_id, tdes, 0, pkt_burst_idx);
 			src_iovec = vec_pool;
 			dst_iovec = vec_pool + (VHOST_MAX_ASYNC_VEC >> 1);
 			src_it = it_pool;
 			dst_it = it_pool + 1;
+			segs_await = 0;
 			vq->async_pkts_inflight_n += n_pkts;
 
 			if (unlikely(n_pkts < (int)pkt_burst_idx)) {