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

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

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?

> - 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.

	--yliu