Hi, Anatoly
We map BAR's with arbitrary addresses, so i don't think we can do much here -
if mmap() returns page-unaligned addresses on platforms with 64K sizes, it's
not our fault.
Maybe we have some misunderstanding here. mmap() returns page-aligned
on my system, but the man page of mmap() ,we found this " offset must be a
multiple of the page size as returned by sysconf(_SC_PAGE_SIZE) ".
So the mmap() must apply of one or more page size, in 64K system, it's
bigger than 16K. When calculate second NIC address(first NIC address + 16K),
the problem arise. I prefer to say that it is a matching problem between
software and system.
We are using Centos 7.6.1810 (AltArch) on arm server, the
default page size is 64K, so we can't do much here.
Best Regards,
Xiaofeng Deng
Turing Business Unit, HiSilicon, HUAWEI
Mobile: (+86)18219206880
Email: [email protected]
-----邮件原件-----
发件人: Burakov, Anatoly [mailto:[email protected]]
发送时间: 2019年11月6日 18:35
收件人: David Marchand <[email protected]>; Wangyu (Eric)
<[email protected]>
抄送: dengxiaofeng <[email protected]>; [email protected];
[email protected]; Linuxarm <[email protected]>; humin (Q)
<[email protected]>; Liyuan (Larry) <[email protected]>
主题: Re: [dpdk-dev] [PATCH v2] bus/pci: resolve multiple NICs address conflicts
On 06-Nov-19 7:37 AM, David Marchand wrote:
> On Wed, Nov 6, 2019 at 7:16 AM Wangyu (Eric) <[email protected]> wrote:
>>
>>
>> In 64K pagesize system, DPDK will read the size NIC need in
>> uio/uio1/maps/map1/size, when the size small than pagesize(e.g.,82599 is
>> 16K), dev->mem_resource[i].len will be 16K, but the mmap function applies
>> for at least 1 page size, which is 64K.
>> Then second NIC mmap, start address is first NIC address + 16K, which
>> already used by first NIC.
>
> Do you see this issue with vfio?
>
>
>> So if change the size to first NIC address + 64K, problem solved.
>
> You are hacking a description of the device resources to workaround a problem.
> This patch is a no go for me.
>
> Maybe there is something to do with the hint passed to mmap in uio case.
> Adding Anatoly to the loop.
>
