> -----Original Message-----
> From: dapengx...@intel.com <dapengx...@intel.com>
> Sent: Friday, January 8, 2021 6:21 PM
> To: Zhang, Qi Z <qi.z.zh...@intel.com>; Wu, Jingjing <jingjing...@intel.com>;
> Xing, Beilei <beilei.x...@intel.com>; Xu, Ting <ting...@intel.com>
> Cc: dev@dpdk.org; Yu, DapengX <dapengx...@intel.com>; sta...@dpdk.org
> Subject: [PATCH] net/iavf: fix vector id assignment
>
> From: YU DAPENG <dapengx...@intel.com>
>
> The number of MSI-X interrupts on Rx shall be the minimal value of the
> number of available MSI-X interrupts per VF - 1 (the 1 is for miscellaneous
> interrupt) and the number of configured Rx queues.
> The current code break the rule because the number of available MSI-X
> interrupts is used as the first value, but code does not subtract 1 from it.
>
> In normal situation, the first value is larger than the second value. So each
> queue can be assigned a unique vector_id.
>
> For example: 17 available MSI-X interrupts, and 16 available Rx queues per VF;
> but only 4 Rx queues are configured when device is started.
> vector_id:0 is for misc interrupt, vector_id:1 for Rx queue0,
> vector_id:2 for Rx queue1, vector_id:3 for Rx queue2, vector_id:4 for Rx
> queue3.
>
> Current code breaks the rule in this normal situation, because when assign
> vector_ids to interrupt handle, for example, it does not assign
> vector_id:4 to the queue3, but assign vector_id:1 to it, because the condition
> used causes vector_id wrap around too early.
>
Hi, Dapeng,
Could you please further explain in which condition will this error happen?
Seems it requires vf->nb_msix = 3 to make it happen, but I do not notice such
situation.
I know it may be an example, is there any more specific case?
Thanks.
> In iavf_config_irq_map(), the current code does not write data into the last
> element of vecmap[], because of the previous code break. Which cause wrong
> data is sent to PF with opcode VIRTCHNL_OP_CONFIG_IRQ_MAP and cause
> error: VIRTCHNL_STATUS_ERR_PARAM(-5).
>
> If kernel driver supports large VFs (up to 256 queues), different queues can
> be
> assigned same vector_id.
>
> In order to adapt to large VFs and avoid wrapping early, the condition is
> replaced from vec >= vf->nb_msix to vec >= vf->vf_res->max_vectors.
>
> Fixes: d6bde6b5eae9 ("net/avf: enable Rx interrupt")
> Cc: sta...@dpdk.org
>
> Signed-off-by: YU DAPENG <dapengx...@intel.com>
> ---
> drivers/net/iavf/iavf_ethdev.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/iavf/iavf_ethdev.c b/drivers/net/iavf/iavf_ethdev.c
> index 7e3c26a94..d730bb156 100644
> --- a/drivers/net/iavf/iavf_ethdev.c
> +++ b/drivers/net/iavf/iavf_ethdev.c
> @@ -483,6 +483,7 @@ static int iavf_config_rx_queues_irqs(struct
> rte_eth_dev *dev,
> struct iavf_qv_map *qv_map;
> uint16_t interval, i;
> int vec;
> + uint16_t max_vectors;
>
> if (rte_intr_cap_multiple(intr_handle) &&
> dev->data->dev_conf.intr_conf.rxq) { @@ -570,15 +571,16 @@
> static int iavf_config_rx_queues_irqs(struct rte_eth_dev *dev,
> /* If Rx interrupt is reuquired, and we can use
> * multi interrupts, then the vec is from 1
> */
> - vf->nb_msix = RTE_MIN(vf->vf_res->max_vectors,
> - intr_handle->nb_efd);
> + max_vectors =
> + vf->vf_res->max_vectors -
> IAVF_RX_VEC_START;
> + vf->nb_msix = RTE_MIN(max_vectors, intr_handle-
> >nb_efd);
> vf->msix_base = IAVF_RX_VEC_START;
> vec = IAVF_RX_VEC_START;
> for (i = 0; i < dev->data->nb_rx_queues; i++) {
> qv_map[i].queue_id = i;
> qv_map[i].vector_id = vec;
> intr_handle->intr_vec[i] = vec++;
> - if (vec >= vf->nb_msix)
> + if (vec >= vf->vf_res->max_vectors)
> vec = IAVF_RX_VEC_START;
> }
> vf->qv_map = qv_map;
> --
> 2.27.0
