Jason Wang
2020-Dec-10 09:11 UTC
[PATCH v1] vdpa/mlx5: Use write memory barrier after updating CQ index
On 2020/12/9 ??10:00, Eli Cohen wrote:> Make sure to put dma write memory barrier after updating CQ consumer > index so the hardware knows that there are available CQE slots in the > queue. > > Failure to do this can cause the update of the RX doorbell record to get > updated before the CQ consumer index resulting in CQ overrun. > > Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices") > Signed-off-by: Eli Cohen <elic at nvidia.com> > --- > V0 -> V1 > Use dma_wmb() instead of wmb()Acked-by: Jason Wang <jasowang at redhat.com>> > drivers/vdpa/mlx5/net/mlx5_vnet.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c > index db87abc3cb60..43b0069ff8b1 100644 > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c > @@ -479,6 +479,11 @@ static int mlx5_vdpa_poll_one(struct mlx5_vdpa_cq *vcq) > static void mlx5_vdpa_handle_completions(struct mlx5_vdpa_virtqueue *mvq, int num) > { > mlx5_cq_set_ci(&mvq->cq.mcq); > + > + /* make sure CQ cosumer update is visible to the hardware before updating > + * RX doorbell record. > + */ > + dma_wmb(); > rx_post(&mvq->vqqp, num); > if (mvq->event_cb.callback) > mvq->event_cb.callback(mvq->event_cb.private);