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

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 10/4/2021 1:01 PM, Pavan Nikhilesh Bhagavatula wrote:
>> 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.
> 

so is there build error or not?

>>>>>>
>>>>>>> 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
>>>>>>>
>>>>>
>>>
>