[dpdk-dev] [PATCH v3 01/11] eal/pci: introduce PCI driver iova as va flag

Santosh Shukla santosh.shukla at caviumnetworks.com
Tue Jul 11 08:16:21 CEST 2017


Introducing RTE_PCI_DRV_NEED_IOVA_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>
---
 lib/librte_eal/common/include/rte_pci.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/librte_eal/common/include/rte_pci.h b/lib/librte_eal/common/include/rte_pci.h
index 8b123391c..ac79040dd 100644
--- a/lib/librte_eal/common/include/rte_pci.h
+++ b/lib/librte_eal/common/include/rte_pci.h
@@ -202,6 +202,8 @@ struct rte_pci_bus {
 #define RTE_PCI_DRV_INTR_RMV 0x0010
 /** Device driver needs to keep mapped resources if unsupported dev detected */
 #define RTE_PCI_DRV_KEEP_MAPPED_RES 0x0020
+/** Device driver needs iova as va */
+#define RTE_PCI_DRV_NEED_IOVA_VA 0X0040
 
 /**
  * A structure describing a PCI mapping.
-- 
2.13.0



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