[dpdk-dev] [PATCH] igb_uio: map dummy dma forcing iommu domain attachment

[Ferruh Yigit]

On 1/18/2017 12:27 PM, Alejandro Lucero wrote:
> For using a DPDK app when iommu is enabled, it requires to
> add iommu=pt to the kernel command line. But using igb_uio driver
> makes DMAR errors because the device has not an IOMMU domain.
> 
> Since kernel 3.15, iommu=pt requires to use the internal kernel
> DMA API for attaching the device to the IOMMU 1:1 mapping, aka
> si_domain. Previous versions did attach the device to that
> domain when intel iommu notifier was called.
> 
> This is not a problem if the driver does later some call to the
> DMA API because the mapping can be done then. But DPDK apps do
> not use that DMA API at all.
> 
> Doing this dma map and unmap is harmless even when iommu is not
> enabled at all.
> 
> Signed-off-by: Alejandro Lucero <alejandro.lucero at netronome.com>

Acked-by: Ferruh Yigit <ferruh.yigit at intel.com>

(I suggest getting this early in 17.05 release, so it can be tested more)