[v2,3/4] vhost: fix async vector buffer overrun
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Commit Message
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(-)
@@ -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) : \
@@ -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:
+ * - bufferred 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)) {