[dpdk-dev] [PATCH v7 7/9] linuxapp/eal_vfio: honor iova mode before mapping

[Jonas Pfefferle1]

Thomas Monjalon <thomas at monjalon.net> wrote on 11/02/2017 11:17:10 AM:

> From: Thomas Monjalon <thomas at monjalon.net>
> To: Jonas Pfefferle1 <JPF at zurich.ibm.com>
> Cc: dev at dpdk.org, Santosh Shukla
> <santosh.shukla at caviumnetworks.com>, jerin.jacob at caviumnetworks.com,
> hemant.agrawal at nxp.com, olivier.matz at 6wind.com,
> maxime.coquelin at redhat.com, sergio.gonzalez.monroy at intel.com,
> bruce.richardson at intel.com, shreyansh.jain at nxp.com,
> gaetan.rivet at 6wind.com, anatoly.burakov at intel.com,
> stephen at networkplumber.org, aconole at redhat.com
> Date: 11/02/2017 11:17 AM
> Subject: Re: [dpdk-dev] [PATCH v7 7/9] linuxapp/eal_vfio: honor iova
> mode before mapping
>
> Hi
>
> 26/10/2017 14:57, Jonas Pfefferle1:
> >
> > Hi @all
> >
> > I just stumbled upon this patch while testing on POWER. RTE_IOVA_VA
will
> > not work for the sPAPR code since the dma window size is currently
> > determined by the physical address only.
>
> Is it    affecting POWER8?

It is.

>
> > I'm preparing a patch to address this.
>
> Any news?
> Can you use virtual addresses?

After a long discussion with Alexey (CC) we came to the conclusion that
with the current sPAPR iommu driver we cannot use virtual addresses since
the iova is restricted to lay in the DMA window which itself is restricted
to physical RAM addresses resp. with the current code 0 to hotplug memory
max. However, Alexey is working on a patch to lift this restriction on the
DMA window size which should allow us to do VA:VA mappings in the future.
For now we should fall back to PA in the dynamic iova mode check. I will
send an according patch later today.

>
>