Re: [PATCH] eal: map io resources for non x86 architectures

[Santosh Shukla <sshukla@mvista.com>]

On Fri, Dec 18, 2015 at 6:25 PM, Santosh Shukla <sshukla@mvista.com> wrote:
> On Fri, Dec 18, 2015 at 1:51 PM, Yuanhan Liu
> <yuanhan.liu@linux.intel.com> wrote:
>> On Fri, Dec 18, 2015 at 01:24:41PM +0530, Santosh Shukla wrote:
>>> >> I guess we have done enough evaluation / investigation that suggest -
>>> >> so to map iopci region to userspace in arch agnostic-way -
>>> >>
>>> >> # either we need to modify kernel
>>> >>                - Make sure all the non-x86 arch to support mapping for
>>> >> iopci region (i.e. pci_mmap_page_range). I don;t think its a correct
>>> >> approach though.
>>> >>             or
>>> >>                - include /dev/ioport char-mem device file who could do
>>> >> more than byte operation, Note that this implementation does not exist
>>> >> in kernel.  I could send an RFC to lkml.
>>> >
>>> > Maybe you could propose the two to lkml, to get some feedbacks from
>>> > those kernel/ARM gurus? Please cc me if you do so.
>>> >
>>>
>>> The latter one I already shared old lkml thread, Pl. revisit my v1 0/6
>>> patch [1] and in that refer [2].
>>
>> Oops, sorry, a bit busy, that I didn't look at it carefully. My bad,
>> anyway.
>>
>>> Josh has already proposed to lkml but for some reason thread didn't
>>> went far. I can restart that discussion giving dpdk use-case as an
>>> example/ requirement.
>>
>> I had a quick go through of the discussion. Both hpa and Arnd seem
>> to be fine with the ioctl interface on /dev/port. Have you tried
>> that?  And if you want to restart it, ioctl might be a better option
>> than /dev/ioport, judging from the discussion.
>>
>
> I tried legacy patch and re-writing with ioctl-way; doing changes in
> dpdk port as well in kernel, had to test on quite other hw not only
> arm64 though! so it will take time for me, I am travelling tomorrow so
> bit delayed, We'll post patch to lkml and share dpdk-virtio feedback
> perhaps by Monday.
>

I posted a query about /dev/ioports approach in lkml thread [1], and
Arnd suggested to use vfio framework but it looks like vfio too does
not map ioresource_io region. Same communicated to Arnd and waiting
for his reply.

In mean time I like to ask general question;
- Has anyone tried vfio/non-iommu approach for virtio pmd driver? If
not then Is there any plan? Someone planning to take up.
[1] https://lkml.org/lkml/2015/12/23/145