[dpdk-dev] [PATCH v3] drivers: advertise kmod dependencies in pmdinfo

[Ferruh Yigit]

On 12/19/2016 12:42 PM, Neil Horman wrote:
> On Fri, Dec 16, 2016 at 02:19:59PM +0000, Ferruh Yigit wrote:
>> On 12/16/2016 12:37 PM, Neil Horman wrote:
>>> On Fri, Dec 16, 2016 at 10:22:08AM +0100, Olivier Matz wrote:
>>>> Hi,
>>>>
>>>> On Thu, 15 Dec 2016 09:22:07 -0800, Stephen Hemminger
>>>> <stephen at networkplumber.org> wrote:
>>>>> On Thu, 15 Dec 2016 11:09:12 -0500
>>>>> Neil Horman <nhorman at tuxdriver.com> wrote:
>>>>>
>>>>>> On Thu, Dec 15, 2016 at 02:46:39PM +0100, Olivier Matz wrote:  
>>>>>>> Add a new macro RTE_PMD_REGISTER_KMOD_DEP() that allows a driver
>>>>>>> to declare the list of kernel modules required to run properly.
>>>>>>>
>>>>>>> Today, most PCI drivers require uio/vfio.
>>>>>>>
>>>>>>> Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
>>>>>>> Acked-by: Fiona Trahe <fiona.trahe at intel.com>
>>>>>>> ---
>>>>>>>
>>>>>>> v2 -> v3:
>>>>>>> - fix kmods deps advertised by mellanox drivers as pointed out
>>>>>>>   by Adrien
>>>>>>>
>>>>>>> v1 ->
>>>>>>> v2:                                                                                                
>>>>>>> - do not advertise uio_pci_generic for vf drivers
>>>>>>> - rebase on top of head: use new driver names and prefix
>>>>>>>   macro with
>>>>>>> RTE_                                                                                       
>>>>>>>
>>>>>>> rfc -> v1:
>>>>>>> - the kmod information can be per-device using a modalias-like
>>>>>>>   pattern
>>>>>>> - change syntax to use '&' and '|' instead of ',' and ':'
>>>>>>> - remove useless prerequisites in kmod lis: no need to
>>>>>>>   specify both uio and uio_pci_generic, only the latter is
>>>>>>>   required
>>>>>>> - update kmod list in szedata2 driver
>>>>>>> - remove kmod list in qat driver: it requires more than just
>>>>>>> loading a kmod, which is described in documentation
>>>>>>>
>>>>>>>  buildtools/pmdinfogen/pmdinfogen.c      |  1 +
>>>>>>>  buildtools/pmdinfogen/pmdinfogen.h      |  1 +
>>>>>>>  drivers/net/bnx2x/bnx2x_ethdev.c        |  2 ++
>>>>>>>  drivers/net/bnxt/bnxt_ethdev.c          |  1 +
>>>>>>>  drivers/net/cxgbe/cxgbe_ethdev.c        |  1 +
>>>>>>>  drivers/net/e1000/em_ethdev.c           |  1 +
>>>>>>>  drivers/net/e1000/igb_ethdev.c          |  2 ++
>>>>>>>  drivers/net/ena/ena_ethdev.c            |  1 +
>>>>>>>  drivers/net/enic/enic_ethdev.c          |  1 +
>>>>>>>  drivers/net/fm10k/fm10k_ethdev.c        |  1 +
>>>>>>>  drivers/net/i40e/i40e_ethdev.c          |  1 +
>>>>>>>  drivers/net/i40e/i40e_ethdev_vf.c       |  1 +
>>>>>>>  drivers/net/ixgbe/ixgbe_ethdev.c        |  2 ++
>>>>>>>  drivers/net/mlx4/mlx4.c                 |  2 ++
>>>>>>>  drivers/net/mlx5/mlx5.c                 |  1 +
>>>>>>>  drivers/net/nfp/nfp_net.c               |  1 +
>>>>>>>  drivers/net/qede/qede_ethdev.c          |  2 ++
>>>>>>>  drivers/net/szedata2/rte_eth_szedata2.c |  2 ++
>>>>>>>  drivers/net/thunderx/nicvf_ethdev.c     |  1 +
>>>>>>>  drivers/net/virtio/virtio_ethdev.c      |  1 +
>>>>>>>  drivers/net/vmxnet3/vmxnet3_ethdev.c    |  1 +
>>>>>>>  lib/librte_eal/common/include/rte_dev.h | 25
>>>>>>> +++++++++++++++++++++++++ tools/dpdk-pmdinfo.py
>>>>>>> |  5 ++++- 23 files changed, 56 insertions(+), 1 deletion(-)
>>>>>>>     
>>>>>> Its odd that all devices, regardless of vendor should depend on the
>>>>>> igb_uio module.  It seems to me that depending on uio_pci_generic
>>>>>> or vfio is sufficient.
>>>>
>>>> igb_uio is the historical uio module of dpdk. Although it is called
>>>> igb_uio, it is not specific to Intel drivers.
>>>>
>>>> Most drivers declare "igb_uio | uio_pci_generic | vfio", which means
>>>> that any of the 3 kernel modules can be used.
>>>>
>>>> I think there are some cases where people will prefer using igb_uio,
>>>> for instance to use a vf pmd in a vm where there is no iommu,
>>>> and where the kernel vfio module does not support the no-iommu mode.
>>>>
>>>>
>>>>>
>>>>> Yes it seems just a special case extension for Mellanox drivers.
>>>>
>>>> Kmod deps are different whether it's a vf driver or not.
>>>> Mellanox drivers are not the only drivers that do not require uio,
>>>> there is also szedata2.
>>>>
>>>> Is it an argument for not including this patch?
>>>>
>>> Speaking only for myself, I'm not suggesting the patch not be included, only
>>> questioning the need to list igb_uio as an optional dependency.  From what I
>>> understand uio_pci_generic is equaly capable of being used in a vf as igb_uio,
>>> and so it seems like its sufficient to list in the deps alone, or am I missing
>>> something?
>>>
>>> Additionally, in regards to the comment about rebasing on net-next here, I don't
>>> think thats needed.  This patch is built such that you will be able to apply
>>> this tag to additional drivers later, as they get merged into thomas's tree, you
>>> don't need to get them all in one shot.
>>
>> Right, more drivers can be added later. But also I don't see any problem
>> if this patch rebased on next-net and be a more complete patch. That is
>> why it was a question to the author.
>>
> Right, it certainly doesn't hurt anything to do so, but given that:
> 
> 1) We're on v3 of this patch
> 2) Not including information in all drivers isn't catastrophic
> 3) Rebasing on net-next still leaves the crypto drivers unaccounted for

If this patch will be extended with a new version to include crypto
drivers, yes I agree it fits better into main tree.

> 
> It seems to me that including the patch now, so that the infrastructure is in
> place for driver maintainers to add the macro on their own in their respective
> trees seems like the more expiedient course of action.
> 
> Best
> Neil
>