From: Jason Wang <jasowang@redhat.com>
To: Eli Cohen <elic@nvidia.com>,
mst@redhat.com, virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Cc: lulu@redhat.com
Subject: Re: [PATCH] vdpa/mlx5: Use write memory barrier after updating CQ index
Date: Mon, 7 Dec 2020 10:51:44 +0800 [thread overview]
Message-ID: <dd7cde10-2e75-1bd3-68ad-f4988274b37d@redhat.com> (raw)
In-Reply-To: <20201206105719.123753-1-elic@nvidia.com>
On 2020/12/6 下午6:57, Eli Cohen wrote:
> Make sure to put 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.
>
> Change-Id: Ib0ae4c118cce524c9f492b32569179f3c1f04cc1
> Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
> Signed-off-by: Eli Cohen <elic@nvidia.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 1f4089c6f9d7..295f46eea2a5 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -478,6 +478,11 @@ 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.
> + */
> + wmb();
> rx_post(&mvq->vqqp, num);
> if (mvq->event_cb.callback)
> mvq->event_cb.callback(mvq->event_cb.private);
Acked-by: Jason Wang <jasowang@redhat.com>
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next parent reply other threads:[~2020-12-07 2:51 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20201206105719.123753-1-elic@nvidia.com>
2020-12-07 2:51 ` Jason Wang [this message]
[not found] ` <20201208091500.GA17763@mtl-vdi-166.wap.labs.mlnx>
2020-12-08 13:53 ` [PATCH] vdpa/mlx5: Use write memory barrier after updating CQ index Michael S. Tsirkin
2020-12-08 21:45 ` Michael S. Tsirkin
[not found] ` <20201209060230.GA57362@mtl-vdi-166.wap.labs.mlnx>
2020-12-09 6:46 ` Michael S. Tsirkin
[not found] ` <20201209065846.GA59515@mtl-vdi-166.wap.labs.mlnx>
2020-12-09 8:05 ` Michael S. Tsirkin
[not found] ` <20201209093836.GA62204@mtl-vdi-166.wap.labs.mlnx>
2020-12-09 12:47 ` Michael S. Tsirkin
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