[dpdk-dev] [PATCH v6 01/12] eal/pci: introduce PCI driver iova as va flag

Aaron Conole aconole at redhat.com
Thu Aug 17 14:35:06 CEST 2017


Santosh Shukla <santosh.shukla at caviumnetworks.com> writes:

> Introducing RTE_PCI_DRV_IOVA_AS_VA flag. Flag used when driver needs
> to operate in iova=va mode.
>
> Why driver need iova=va mapping?
>
> On NPU style co-processors like Octeontx, the buffer recycling has been
> done in HW, unlike SW model. Here is the data flow:
> 1) On control path, Fill the HW mempool with buffers(iova as pa address)
> 2) on rx_burst, HW gives you IOVA address(iova as pa address)
> 3) As application expects VA to operate on it, rx_burst() needs to
> convert to _va from _pa. Which is very expensive.
> Instead of that if iova as va mapping, we can avoid the cost of
> converting with help of IOMMU/SMMU.
>
> Signed-off-by: Santosh Shukla <santosh.shukla at caviumnetworks.com>
> Signed-off-by: Jerin Jacob <jerin.jacob at caviumnetworks.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> ---

This should be folded into patch 5;  there's no clear need for it until
then.


More information about the dev mailing list