[dpdk-dev] [PATCH v2 12/18] eal: add generic device declaration parameter

[Gaëtan Rivet]

On Wed, Dec 13, 2017 at 07:56:42PM +0530, Shreyansh Jain wrote:
> On Thursday 12 October 2017 01:51 PM, Gaetan Rivet wrote:
> > Add a new generic device declaration parameter:
> > 
> >     --dev=<device_declaration>
> > 
> 
> [...]
> 
> > 
> > diff --git a/lib/librte_eal/common/eal_common_options.c b/lib/librte_eal/common/eal_common_options.c
> > index 603df27..b7591fd 100644
> > --- a/lib/librte_eal/common/eal_common_options.c
> > +++ b/lib/librte_eal/common/eal_common_options.c
> > @@ -95,6 +95,7 @@ eal_long_options[] = {
> >   	{OPT_PROC_TYPE,         1, NULL, OPT_PROC_TYPE_NUM        },
> >   	{OPT_SOCKET_MEM,        1, NULL, OPT_SOCKET_MEM_NUM       },
> >   	{OPT_SYSLOG,            1, NULL, OPT_SYSLOG_NUM           },
> > +	{OPT_DEV,               1, NULL, OPT_DEV_NUM              },
> >   	{OPT_VDEV,              1, NULL, OPT_VDEV_NUM             },
> >   	{OPT_VFIO_INTR,         1, NULL, OPT_VFIO_INTR_NUM        },
> >   	{OPT_VMWARE_TSC_MAP,    0, NULL, OPT_VMWARE_TSC_MAP_NUM   },
> > @@ -1120,6 +1121,21 @@ eal_parse_common_option(int opt, const char *optarg,
> >   		}
> >   		break;
> > +	case OPT_DEV_NUM: {
> > +		struct rte_devargs da;
> > +		int ret;
> > +
> > +		if (rte_eal_devargs_parse(&da, optarg) < 0)
> > +			return -1;
> > +		ret = rte_bus_probe_mode_set(da.bus->name,
> > +					RTE_BUS_PROBE_WHITELIST);
> > +		if (ret < 0 && ret != -ENOTSUP)
> > +			return -1;
> > +		if (eal_option_device_add(NULL, optarg) < 0)
> > +			return -1;
> > +	}
> 
> Might be a naive question: Any specific reason why we don't add the devices
> directly into devargs_list here (eal_parse_args -> eal_parse_common_option
> -> OPT_DEV ->) rather than wait for eal to call eal_option_device_parse
> again?
> 
> Is it to allow eal_plugins_init() to finish?
> 

Yes. And actually this makes me aware of an issue with this
implementation.

Calling rte_eal_devargs_parse here is premature, and
rte_bus_probe_mode_set as well.

eal_plugins_init() must be executed before calling rte_devargs to allow
for buses introduced as plugins to be able to recognize their devices.

I will reorder a few things in eal_options, thanks for catching this.

> > +		break;
> > +
> >   	case OPT_VDEV_NUM:
> >   		if (eal_option_device_add("vdev", optarg) < 0)
> >   			return -1;
> 
> [...]
> 

-- 
Gaëtan Rivet
6WIND