# Re: New commands to configure IOV features

- From: Yinghai Lu \<yinghai@kernel.org\>
- Date: 2012-09-20 00:19:47 
- List: netdev
- Page: https://ratatoskr.run/netdev/2012/09/10904428
- Thread: https://ratatoskr.run/netdev/2012/05/10894658/t.md

```text
On Wed, Sep 19, 2012 at 3:46 PM, Ben Hutchings
[ref] wrote:
> On Wed, 2012-09-19 at 15:17 -0700, Yinghai Lu wrote:
>> +max_vfs_store(struct device *dev, struct device_attribute *attr,
>> +                const char *buf, size_t count)
>> +{
>> +       unsigned long val;
>> +       struct pci_dev *pdev = to_pci_dev(dev);
>> +
>> +       if (strict_strtoul(buf, 0, &val) < 0)
>> +               return -EINVAL;
>> +
>> +       pdev->max_vfs = val;
>> +
>> +       return count;
>> +}
> [...]
>
> Then what would actually trigger creation of the VFs?  There's no way we
> can assume that some sysfs attribute will be written before the PF
> driver is loaded (what if it's built-in?).  I thought the idea was to
> add a driver callback that would be called when the sysfs attribute was
> written.

could just stop the device and add it back again?

just like updated patch.

Thanks

Yinghai
```

## Attachments

- [sriov\_xxx.patch](https://ratatoskr.run/netdev/2012/09/10904428/attachment/0) (application/octet-stream, 3664 bytes)