Re: [dpdk-dev] [PATCH v5 1/3] net/thunderx: enable build only on 64-bit Linux

[Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>]

>On 10/4/2021 12:34 PM, Pavan Nikhilesh Bhagavatula wrote:
>>> On 10/4/2021 11:02 AM, Pavan Nikhilesh Bhagavatula wrote:
>>>>> On 10/4/2021 6:56 AM, pbhagavatula@marvell.com wrote:
>>>>>> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>>>>>>
>>>>>> Due to Linux kernel AF(Admin function) driver dependency, only
>>>>> enable
>>>>>> build for 64-bit Linux.
>>>>>>
>>>>>
>>>>> Hi Pavan,
>>>>>
>>>>> Isn't it possible to provide a commit log in the kernel side etc, that
>let
>>>>> others to verify why only 64 bit is required, or if someone want to
>>>>> support
>>>>> 32bit that may help them to investigate the source of the
>restriction.
>>>>
>>>> Arch 32 support is not implemented on ThunderX, so 32bit will not
>>> run.
>>>>
>>>
>>> I see, is following correct:
>>> All thunderx, octeonx & octeontx2 only supports VF in the DPDK,
>and PF
>>> is
>>> supported by Linux kernel driver. And Linux kernel driver doesn't
>>> support arch32.
>>
>> AF != PF, AF is something that manages all the shared resources
>between PF/VF.
>>
>
>I see, I though AF is part of PF functionality. Are there two different
>kernel
>modules for PF and AF?
>
>So can DPDK driver drive PF? In a way, PF by DPDK, VF by DPDK, AF by
>Linux
>kernel driver.

Yup that’s correct.

>
>>>
>>> Is something changed in kernel driver side to drop the 32bit support?
>>> If it was not supported at all, what is the motivation to disable the
>DPDK
>>> drivers now?
>>>
>>
>> It was never supported to begin with, motivation is that build will fail if
>we try to
>> compile with 32b.
>>
>
>If there is no plan to support 32bit in the kernel side, that is reasonable
>to
>disable 32bit build, please provide above details in the commit log.
>
>And after above said, how much maintenance cost to support 32bit, if
>the build
>error is on the logging format "%lx" etc .. (as we mostly have 32bit build
>errors), it is better to fix them using 'PRIx64' which is more proper way
>anyway. If there is more logical issue with 32bit pointers, I agree with
>you to
>disable it.
>Can you please provided the build error in the commit log as record?
>

Apologies, I meant that all the functions that don’t fall under 64b are stubbed out
so the driver wouldn’t work.

>>>>>
>>>>>> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
>>>>>> Acked-by: Jerin Jacob <jerinj@marvell.com>
>>>>>> ---
>>>>>>  v5 Changes
>>>>>>  - s/fuction/function.
>>>>>>
>>>>>>  v4 Changes:
>>>>>>  - Update commit message regarding dependency on AF driver.
>>>>>>
>>>>>>  drivers/net/thunderx/meson.build | 4 ++--
>>>>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/net/thunderx/meson.build
>>>>> b/drivers/net/thunderx/meson.build
>>>>>> index 4bbcea7f93..da665bd76f 100644
>>>>>> --- a/drivers/net/thunderx/meson.build
>>>>>> +++ b/drivers/net/thunderx/meson.build
>>>>>> @@ -1,9 +1,9 @@
>>>>>>  # SPDX-License-Identifier: BSD-3-Clause
>>>>>>  # Copyright(c) 2017 Cavium, Inc
>>>>>>
>>>>>> -if is_windows
>>>>>> +if not is_linux or not dpdk_conf.get('RTE_ARCH_64')
>>>>>>      build = false
>>>>>> -    reason = 'not supported on Windows'
>>>>>> +    reason = 'only supported on 64-bit Linux'
>>>>>>      subdir_done()
>>>>>>  endif
>>>>>>
>>>>>> --
>>>>>> 2.17.1
>>>>>>
>>>>
>>