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

Ferruh Yigit ferruh.yigit at intel.com
Fri Dec 16 15:19:59 CET 2016


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.

> More to the point, there are crypto
> drivers that may make use of this module dependency tag, and those are also
> missing.  I would suggest taking the patch based on it current state (once the
> above igb_uio issue is settled), and then adding the tag to new drivers in
> subsequent releases as they get merged.
> 
> Neil
> 
>>
>> Regards,
>> Olivier
>>



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