From ca4cc612d7b0faf1b93db57e303d8ca351c97f90 Mon Sep 17 00:00:00 2001 From: Matan Azrad Date: Mon, 27 Jul 2020 14:00:44 +0000 Subject: [PATCH] vdpa/mlx5: fix notification timing The issue is relevant only for the timer event modes: 0 and 1. When the HW finishes to consume a burst of the guest Rx descriptors, it creates a CQE in the CQ. When traffic stops, the mlx5 driver arms the CQ to get a notification when a specific CQE index is created - the index to be armed is the next CQE index which should be polled by the driver. The mlx5 driver configured the kernel driver to send notification to the guest callfd in the same time of the armed CQE event. It means that the guest was notified only for each first CQE in a poll cycle, so if the driver polled CQEs of all the virtio queue available descriptors, the guest was not notified again for the rest because there was no any new CQE to trigger the guest notification. Hence, the Rx queues might be stuck when the guest didn't work with poll mode. Remove prior kernel notification, and do manual notification after CQ polling. Fixes: a9dd7275a149 ("vdpa/mlx5: optimize notification events") Signed-off-by: Matan Azrad Acked-by: Xueming Li Reviewed-by: Maxime Coquelin --- drivers/vdpa/mlx5/mlx5_vdpa_event.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) diff --git a/drivers/vdpa/mlx5/mlx5_vdpa_event.c b/drivers/vdpa/mlx5/mlx5_vdpa_event.c index e14b380f19..0414c9129a 100644 --- a/drivers/vdpa/mlx5/mlx5_vdpa_event.c +++ b/drivers/vdpa/mlx5/mlx5_vdpa_event.c @@ -172,17 +172,6 @@ mlx5_vdpa_cq_create(struct mlx5_vdpa_priv *priv, uint16_t log_desc_n, rte_errno = errno; goto error; } - if (callfd != -1 && - priv->event_mode != MLX5_VDPA_EVENT_MODE_ONLY_INTERRUPT) { - ret = mlx5_glue->devx_subscribe_devx_event_fd(priv->eventc, - callfd, - cq->cq->obj, 0); - if (ret) { - DRV_LOG(ERR, "Failed to subscribe CQE event fd."); - rte_errno = errno; - goto error; - } - } cq->callfd = callfd; /* Init CQ to ones to be in HW owner in the start. */ cq->cqes[0].op_own = MLX5_CQE_OWNER_MASK; @@ -352,11 +341,11 @@ mlx5_vdpa_interrupt_handler(void *cb_arg) struct mlx5_vdpa_virtq, eqp); mlx5_vdpa_cq_poll(cq); + /* Notify guest for descs consuming. */ + if (cq->callfd != -1) + eventfd_write(cq->callfd, (eventfd_t)1); if (priv->event_mode == MLX5_VDPA_EVENT_MODE_ONLY_INTERRUPT) { mlx5_vdpa_cq_arm(priv, cq); - /* Notify guest for descs consuming. */ - if (cq->callfd != -1) - eventfd_write(cq->callfd, (eventfd_t)1); return; } /* Don't arm again - timer will take control. */ -- 2.20.1