On Fri, Feb 09, 2018 at 03:26:53PM +0100, Maxime Coquelin wrote:
> This patch fixes traffic resuming issue seen when using
> Rx vector path.
>
> Fixes: efc83a1e7fc3 ("net/virtio: fix queue setup consistency")
>
> Signed-off-by: Tiwei Bie <tiwei....@intel.com>
> Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
Proposed change for a more detailed commit log (thanks Tiwei for
the explanation):
Since commit efc83a1e7fc3 ("net/virtio: fix queue setup consistency"),
when resuming a virtio port, the rx rings are refilled with new mbufs
until they are full (vq->vq_free_cnt == 0). This is done without
ensuring that the descriptor index remains a multiple of
RTE_VIRTIO_VPMD_RX_REARM_THRESH, which is a prerequisite when using the
vector mode. This can cause an out of bound access in the rx ring.
This commit changes the vector refill method from
virtqueue_enqueue_recv_refill_simple() to virtio_rxq_rearm_vec(), which
properly checks that the refill is done by batch of
RTE_VIRTIO_VPMD_RX_REARM_THRESH.
> ---
> drivers/net/virtio/virtio_rxtx.c | 34
> ++++++++++++++++++---------------
> drivers/net/virtio/virtio_rxtx_simple.c | 2 +-
> drivers/net/virtio/virtio_rxtx_simple.h | 2 +-
> 3 files changed, 21 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/net/virtio/virtio_rxtx.c
> b/drivers/net/virtio/virtio_rxtx.c
> index 854af399e..505283edd 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -30,6 +30,7 @@
> #include "virtio_pci.h"
> #include "virtqueue.h"
> #include "virtio_rxtx.h"
> +#include "virtio_rxtx_simple.h"
>
> #ifdef RTE_LIBRTE_VIRTIO_DEBUG_DUMP
> #define VIRTIO_DUMP_PACKET(m, len) rte_pktmbuf_dump(stdout, m, len)
> @@ -446,25 +447,28 @@ virtio_dev_rx_queue_setup_finish(struct rte_eth_dev
> *dev, uint16_t queue_idx)
> &rxvq->fake_mbuf;
> }
>
> - while (!virtqueue_full(vq)) {
> - m = rte_mbuf_raw_alloc(rxvq->mpool);
> - if (m == NULL)
> - break;
> + if (hw->use_simple_rx) {
> + while (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
> + virtio_rxq_rearm_vec(rxvq);
> + nbufs += RTE_VIRTIO_VPMD_RX_REARM_THRESH;
> + }
> + } else {
> + while (!virtqueue_full(vq)) {
> + m = rte_mbuf_raw_alloc(rxvq->mpool);
> + if (m == NULL)
> + break;
>
> - /* Enqueue allocated buffers */
> - if (hw->use_simple_rx)
> - error = virtqueue_enqueue_recv_refill_simple(vq, m);
> - else
It looks that virtqueue_enqueue_recv_refill_simple() is not used anymore.
We may want to remove it.
It means this patch also fixes the issue related to the patch I've just
submitted [1]. To ease backport process, I think the patch [1] is still
relevant because it fixes an older commit.
[1] http://dpdk.org/dev/patchwork/patch/35130/
> + /* Enqueue allocated buffers */
> error = virtqueue_enqueue_recv_refill(vq, m);
> -
> - if (error) {
> - rte_pktmbuf_free(m);
> - break;
> + if (error) {
> + rte_pktmbuf_free(m);
> + break;
> + }
> + nbufs++;
> }
> - nbufs++;
> - }
>
> - vq_update_avail_idx(vq);
> + vq_update_avail_idx(vq);
> + }
>
> PMD_INIT_LOG(DEBUG, "Allocated %d bufs", nbufs);
>
> virtio_rxq_vec_setup(rxvq);
Another thing seen by Tiwei: virtio_rxq_vec_setup() should be called
before virtio_rxq_rearm_vec() because it initializes the mbuf
initializer.
Thanks,
Olivier
