lkml.org 
[lkml]   [2020]   [Dec]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.10 488/717] vdpa/mlx5: Use write memory barrier after updating CQ index
    Date
    From: Eli Cohen <elic@nvidia.com>

    [ Upstream commit 83ef73b27eb2363f44faf9c3ee28a3fe752cfd15 ]

    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@nvidia.com>
    Link: https://lore.kernel.org/r/20201209140004.15892-1-elic@nvidia.com
    Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    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 1fa6fcac82992..81b932f72e103 100644
    --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
    +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
    @@ -464,6 +464,11 @@ 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);
    --
    2.27.0


    \
     
     \ /
      Last update: 2020-12-28 15:48    [W:4.196 / U:0.996 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site