RE: [PATCH v2] net/iavf: add lock for vf commands

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: Mike Pattrick <mkp@redhat.com>
> Sent: Tuesday, December 20, 2022 11:54 PM
> To: dev@dpdk.org
> Cc: Zhang, Qi Z <qi.z.zhang@intel.com>; thomas@monjalon.net;
> david.marchand@redhat.com; Zhou, YidingX <yidingx.zhou@intel.com>;
> ktraynor@redhat.com; Mike Pattrick <mkp@redhat.com>; stable@dpdk.org
> Subject: [PATCH v2] net/iavf: add lock for vf commands
> 
> iavf admin queue commands aren't thread-safe. Bugs surrounding this issue
> can manifest in a variety of ways but frequently pend_cmd is over written.
> Simultaneously executing commands can result in a misconfigured device or
> DPDK sleeping in a thread for 2 second.
> 
> Despite this limitation, vf commands may be executed from both
> iavf_dev_alarm_handler() in a control thread and the applications main
> thread. This is trivial to simulate in the testpmd application by creating a
> bond of vf's in active backup mode, and then turning the bond off and then
> on again repeatedly.
> 
> Previously [1] was proposed as a potential solution, but this commit did not
> resolve all potential issues concerning the admin queue and has been
> reverted from the stable branch. I propose adding locks until a more
> complete solution is available.
> 
> [1] commit cb5c1b91f76f ("net/iavf: add thread for event callbacks")
> 
> Fixes: 48de41ca11f0 ("net/avf: enable link status update")
> Fixes: 84108425054a ("net/iavf: support asynchronous virtual channel
> message")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Mike Pattrick <mkp@redhat.com>
> 
> ---
> 
> v2:
>  - Added locks around some iavf_execute_vf_cmd calls which were missed  in
> v1
>  - Changed description to indicate that [1] was only reverted out of the  stable
> branch.
> ---
>  drivers/net/iavf/iavf.h       |  1 +
>  drivers/net/iavf/iavf_vchnl.c | 90 +++++++++++++++++++++++++++++++++++
>  2 files changed, 91 insertions(+)
> 
> diff --git a/drivers/net/iavf/iavf.h b/drivers/net/iavf/iavf.h index
> 1edebab8dc..aa18650ffa 100644
> --- a/drivers/net/iavf/iavf.h
> +++ b/drivers/net/iavf/iavf.h
> @@ -262,6 +262,7 @@ struct iavf_info {
>  	struct iavf_qv_map *qv_map; /* queue vector mapping */
>  	struct iavf_flow_list flow_list;
>  	rte_spinlock_t flow_ops_lock;
> +	rte_spinlock_t aq_lock;
>  	struct iavf_parser_list rss_parser_list;
>  	struct iavf_parser_list dist_parser_list;
>  	struct iavf_parser_list ipsec_crypto_parser_list; diff --git
> a/drivers/net/iavf/iavf_vchnl.c b/drivers/net/iavf/iavf_vchnl.c index
> f92daf97f2..edb74edcac 100644
> --- a/drivers/net/iavf/iavf_vchnl.c
> +++ b/drivers/net/iavf/iavf_vchnl.c
> @@ -554,7 +554,9 @@ iavf_enable_vlan_strip(struct iavf_adapter *adapter)
>  	args.in_args_size = 0;
>  	args.out_buffer = vf->aq_resp;
>  	args.out_size = IAVF_AQ_BUF_SZ;
> +	rte_spinlock_lock(&vf->aq_lock);
>  	ret = iavf_execute_vf_cmd(adapter, &args, 0);
> +	rte_spinlock_unlock(&vf->aq_lock);
>  	if (ret)
>  		PMD_DRV_LOG(ERR, "Failed to execute command of"
>  			    " OP_ENABLE_VLAN_STRIPPING");
> @@ -575,7 +577,9 @@ iavf_disable_vlan_strip(struct iavf_adapter *adapter)
>  	args.in_args_size = 0;
>  	args.out_buffer = vf->aq_resp;
>  	args.out_size = IAVF_AQ_BUF_SZ;
> +	rte_spinlock_lock(&vf->aq_lock);
>  	ret = iavf_execute_vf_cmd(adapter, &args, 0);
> +	rte_spinlock_unlock(&vf->aq_lock);
>  	if (ret)
>  		PMD_DRV_LOG(ERR, "Failed to execute command of"
>  			    " OP_DISABLE_VLAN_STRIPPING");
> @@ -604,7 +608,9 @@ iavf_check_api_version(struct iavf_adapter *adapter)
>  	args.out_buffer = vf->aq_resp;
>  	args.out_size = IAVF_AQ_BUF_SZ;
> 
> +	rte_spinlock_lock(&vf->aq_lock);
>  	err = iavf_execute_vf_cmd(adapter, &args, 0);
> +	rte_spinlock_unlock(&vf->aq_lock);

Instead of wrapping lock and unlock every place, can we add a new wrap function e.g.: iavf_execute_vf_cmd_safe?