[dpdk-dev] standardize device identification

[Shreyansh Jain]

On Thursday 21 December 2017 03:32 AM, Thomas Monjalon wrote:
> Changing the title and adding more comments inline:
> 
> 19/12/2017 00:05, Thomas Monjalon:
>> Let's summarize and resume this thread.
>>
>> We need a generic syntax to describe a device.
>> This syntax can be used
>> 	- before initializing the device (i.e. whitelist/blacklist)
>> 	- or after the initialization (e.g. user config)
>>
>> We need to answer 4 questions:
>> 1/ what are the separators (comma, colon, etc)?
>> 2/ how to distinguish a device identification from a configuration?
>> 3/ what are the mandatory parts?
>> 4/ what can be the optional properties?
>>
>> 30/11/2017 08:35, Yuanhan Liu:
>>> What this patch proposes is to use "name[,mac]" syntax. "name" is the
>>> PCI id for pci device. For vdev, it's the vdev name given by user. The
>>> reason "mac" is needed is for some devices (say ConnectX-3), 2 ports
>>> (in a single NIC) have the same PCI id.
>>
>> Based on the feedbacks we had, I suggest a syntax where everything is
>> optional key/value pairs, and split in 3 categories:
>> 	- bus (pci, vdev, vmbus, fslmc, etc)
>> 	- class (eth, crypto)
>> 	- driver (i40e, mlx5, virtio, etc)
> 
> The key/value pair describing the category scope is mandatory
> and must be the first pair in the category properties.
> Example: bus=pci, must be placed before id=0000:01:00.0
> 
>> Between categories, the separator is a slash.

Why is a '/' required as a separator? Are you expecting the key in 
key,value pair to duplicate across categories?

>> Inside a category, the separator is a comma.
>> Inside a key/value pair, the separator is an equal sign.

sounds reasonable to me.

>>
>> It may look like this:
>> bus=BUS_NAME,id=BUS_ID/class=CLASS_NAME,dev_port=PORT_NUM,mac=MAC_ADDRESS/driver=DRIVER_NAME,driverspecificproperty=VALUE

If I take cue from fslmc and dpaa bus:

for fslmc: bus=fslmc,id=dpni.1
            bus=fslmc,id=dpsec.1
for dpaa: bus=dpaa,id=fm1-mac1
           bus=dpaa,id=dpaa-sec1

So, at least from fslmc/dpaa perspective, above fits.

Just want to highlight: in some cases the device names can contain ',' - 
but then, that can be handled at bus scan level.
For dpaa bus, the device identified from platform identifiers contains a 
longer ',' separated string - which is then stripped to form a name like 
'fm1-mac1' before being added to device->name.

>>
>> A device is identified when every properties are matched.

So, a ovs-dpdk user would have to know a dpdk bus to identify a device 
to plug into a OVS bridge?

>> Before device is probed, only the bus category is relevant.
>> For the simple PCI whitelist, it means moving from
>> 	-w 0000:01:00.0
>> to
>> 	-w bus=pci,id=0000:01:00.0

OK

>>
>> It is possible to mix some settings in these devargs syntax if the keys
>> are differents. Example: mac= is for identification by MAC, whereas
>> newmac= would be for specifying a MAC address to set.
>>
>> Agreement?

in principle, yes.
just need clarity on '/' as a separator.

> 
> Yuanhan is proposing to use this syntax in OVS option dpdk-devargs:
> https://mail.openvswitch.org/pipermail/ovs-dev/2017-December/342273.html
> 
> Please, any feedback or approval that this syntax is good?
>