Re: [PATCH v6 6/8] virtio: add vfio api to rd/wr ioport space

[Santosh Shukla <sshukla@mvista.com>]

On Tue, Feb 2, 2016 at 10:49 AM, Yuanhan Liu
<yuanhan.liu@linux.intel.com> wrote:
> On Tue, Feb 02, 2016 at 10:00:36AM +0530, Santosh Shukla wrote:
>> >
>> > BTW, I didn't follow the noIOMMU discussion; how did it end? Do we still
>> > need that? Is this patch a full story to enable virtio on ARM?
>> >
>> Ok, We agreed that explicit __noiommu suffix not required, atleast for
>> rte_xx_drv struct{}, as because sooner than later we'll have virtio
>> working for both flavours ie... iommu/noiommu. My only worry was
>> parsing for _noiommu and default vfio case, as because noiomu needed
>> user to preset "enable_noiommu_" param for vfio driver to do mode
>> switch. But we wont need that parsing as because if param is not set
>> then binding won't happen, which Thomas rightly pointed out, therefore
>> I choose to drop resource parsing for virtio-for-vfio case, now virtio
>> driver to check only drv->kdrv == RTE_KDRV_VFIO so to make sure
>> interface attached to vfio or not.
>>
>> But perhaps when we have both flavours working for virtio, then we
>> should at least prompt a  INFO message on console that virtio pmd
>> driver attached to default vfio or noIOMMU.
>>
>> So we don't need explicit _noIOMMU.
>
> Thanks for the explanation.
>>
>> Yes this patch is to enable non-x86 arch to use virtio pmd driver
>> (virtio 0.95 spec). After this patch merges-in, I am planning to
>> - replace sys/io.h entirely
>
> Hmm, be more specific? Replace it with what?
>

Just to remove ifdef clutter in general from dpdk source and mo

>> - Add raw_read/raw_writel() api for arm/arm64 {Already proposed
>> similar implementation in v2} so that they could use virtio 1.0spec
>> mapped memory, for both UIO/VFIO mode.
>
> PCI memory bar mapping works both with UIO/VFIO on ARM, without
> any extra efforts, right? If so, it should just work with my
> patch set and yours.
>

Mostl likely, That I have not tried. (todo),
>         --yliu