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 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.

>>
>> 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?

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