Re: [dpdk-dev] [PATCH v5 3/3] PCI: don't use vfio ioctl call to access PIO resource

["谢华伟(此时此刻）" <huawei.xhw@alibaba-inc.com>]

On 2021/1/27 18:32, Ferruh Yigit wrote:
> I was waiting for clarification if this can be solved in virtio, which 
> seems clarified and decided to go with this patch, I am OK to proceed 
> with patch 1 & 2.
>
> But first patch changes how PIO address get, it changes the Linux 
> interface used to get the PIO.
> And as far as I can see second patch requires this new interface to be 
> able to access the MEM resources.
>
> I have a concern that this interface change may cause issues with 
> various distros, kernel versions etc.. And prefer it goes through a 
> full -rc1 validation cycle.
>
> Huawei, I am aware the patch is around for a while but to play safe, I 
> suggest considering it for early next release, so it can be tested 
> enough, instead of getting if for -rc2/3 in this release.
>
> Thanks,
> ferruh
>
Hi Ferruh and Maxime:

igb_uio kernel driver gets resource through pci_resource_start, i.e, 
(dev)->resource[(bar)].start

uio_pci_generic and the generic way in my patch 1 gets resource through 
the same interface:

         pci dev driver exports to userspace the bar resource attributes 
through pci_dev->resource (check resource_show in kernel's 
drivers/pci/pci-sysfs.c)

Other arch than x86 uses the same interface in their pci_uio_ioport_map.

So patch 1 is the most generic way and shouldn't break things. 
/proc/ioports should be fully dropped.

Using /proc/ioport is partly my fault at the very beginning. It causes 
so much mess.

Could you please confirm this?

Thanks huawei

>> Could you please post v6?
>>
>> Thanks,
>> Maxime
>>
>>>>
>>>> It is not too late for this release, as the change will not be that
>>>> intrusive. But if you prepare such patch, please base it on top of my
>>>> virtio rework series; To make it easier to you, I added it to the 
>>>> dpdk-
>>>> next-virtio tree:
>>>> https://git.dpdk.org/next/dpdk-next-virtio/log/?h=virtio_pmd_rework_v2
>>>>
>>>> Thanks,
>>>> Maxime
>>>>
>>>