Re: Hotplug

[Tetsuya Mukawa <mukawa@igel.co.jp>]

On 2015/10/07 22:16, Srikanth Akula wrote:
> Thank you for the inputs .
>
> I was able to solve the problem of device notification from my control
> plane.
>
> I would like to know if we have any way to know if the PCI device is
> already attached before we try to attach it ( if the device is already
> attached pci probe will result an error ) .
> But i want to know before hand to verify if the device is already attached
> or not .

Hi  Srikanth,

I guess below API may help you.
(Unfortunately, I am out of office now, so I haven't checked it, but I
guess it works.)

 - struct rte_eth_dev *rte_eth_dev_allocated(const char *name)

If none NULL value is returned, a device has been already attached.
If you want to check a physical NIC, above 'name' parameter will be like
below.

    snprintf(name, size, "%d:%d.%d",
                        pci_dev->addr.bus, pci_dev->addr.devid,
                        pci_dev->addr.function);

Thanks,
Tetsuya

>
> I came with small API which can be used to check if the pci device is
> already bound to any driver .
>
> +int
> +rte_eal_pci_is_attached(const char *devargs)
> +{
> +        struct rte_pci_device *dev = NULL;
> +        struct rte_pci_addr addr;
> +        memset(&addr,0,sizeof(struct rte_pci_addr));
> +
> +        if (eal_parse_pci_DomBDF(devargs, &addr) == 0)
> +          {
> +            TAILQ_FOREACH(dev, &pci_device_list, next) {
> +            if (!rte_eal_compare_pci_addr(&dev->addr, &addr))
> +              {
> +                if (dev->driver)
> +                  {
> +                    /*pci_dump_one_device(stdout,dev);*/
> +                    RTE_LOG(WARNING, EAL, "Requested device " PCI_PRI_FMT
> +                      " cannot be used\n", dev->addr.domain, dev->addr.bus,
> +                    dev->addr.devid, dev->addr.function);
> +                   return -1;
> +                 }
> +              }
> +           }
> +         }
> +   return 0;
> +}
> +
>
> Could you please let me know if it is good to have such APIs
>
> Regards,
> _Srikanth_
>
>
> On Mon, Sep 28, 2015 at 9:44 PM, Stephen Hemminger <
> stephen@networkplumber.org> wrote:
>
>> On Mon, 28 Sep 2015 21:12:50 -0700
>> Srikanth Akula <srikanth044@gmail.com> wrote:
>>
>>> Hello ,
>>>
>>> I am trying to write an application based on DPDK port hotplug feature .
>> My
>>> requirement is to get an event when a new PCI devices gets added to the
>>> system on the go.
>>>
>>> Do we have any in-built mechanism in DPDK (UIO/e1000/vfio drivers ) that
>> i
>>> can use to get notifications when a new device gets added . I know the
>>> alternatives such as inotify etc .
>>>
>>> But i am more interested to get equivalent support in dpdk drivers .
>>>
>>> Please let me know .
>>>
>>> Srikanth
>> Implementing hotplug requires integration with the OS more than any
>> additional
>> DPDK support. What the Brocade vRouter does is leverage the existing Linux
>> udev infrastructure to send a message to the router application which then
>> initializes and sets up the new hardware. Most of the DPDK changes are
>> upstream
>> already and involve being able to dynamically add ports on the fly.
>>
>>