Re: [PATCH 8/9] vfio/pci: export nvlink2 support into vendor vfio_pci drivers

Alexey Kardashevskiy
2021-03-11T01:44:17Z

On 11/03/2021 12:34, Jason Gunthorpe wrote:
> On Thu, Mar 11, 2021 at 12:20:33PM +1100, Alexey Kardashevskiy wrote:
>
>>> It is supposed to match exactly the same match table as the pci_driver
>>> above. We *don't* want different behavior from what the standrd PCI
>>> driver matcher will do.
>>
>> This is not a standard PCI driver though
>
> It is now, that is what this patch makes it into. This is why it now
> has a struct pci_driver.
>
>> and the main vfio-pci won't have a
>> list to match ever.
>
> ?? vfio-pci uses driver_override or new_id to manage its match list

Exactly, no list to update.

>> IBM NPU PCI id is unlikely to change ever but NVIDIA keeps making
>> new devices which work in those P9 boxes, are you going to keep
>> adding those ids to nvlink2gpu_vfio_pci_table?
>
> Certainly, as needed. PCI list updates is normal for the kernel.
>
>> btw can the id list have only vendor ids and not have device ids?
>
> The PCI matcher is quite flexable, see the other patch from Max for
> the igd

ah cool, do this for NVIDIA GPUs then please, I just discovered another
P9 system sold with NVIDIA T4s which is not in your list.

> But best practice is to be as narrow as possible as I hope this will
> eventually impact module autoloading and other details.

The amount of device specific knowledge is too little to tie it up to
device ids, it is a generic PCI driver with quirks. We do not have a
separate drivers for the hardware which requires quirks.

And how do you hope this should impact autoloading?

--
Alexey