-- if the preferred mode is RTE_IOVA_PA but there is no access to Physical
- Addresses, then EAL init fails early, since later probing of the devices
- would fail anyway,
-- if the preferred mode is RTE_IOVA_DC then based on the Physical Addresses
- availability, the preferred mode is adjusted to RTE_IOVA_PA or RTE_IOVA_VA.
- In the case when the buses had disagreed on the IOVA Mode at the first step,
- part of the buses won't work because of this decision.
+ - All drivers are expected to work in RTE_IOVA_VA mode, irrespective of
+ physical address availability.
+ - By default, the mempool, first asks for IOVA-contiguous memory using
+ ``RTE_MEMZONE_IOVA_CONTIG``. This is slow in RTE_IOVA_PA mode and it may
+ affect the application boot time.
+ - It is easy to enable large amount of IOVA-contiguous memory use-cases
+ with IOVA in VA mode.
+
+ It is expected that all PCI drivers work in both RTE_IOVA_PA and
+ RTE_IOVA_VA modes.
+
+ If a PCI driver does not support RTE_IOVA_PA mode, the
+ ``RTE_PCI_DRV_NEED_IOVA_AS_VA`` flag is used to dictate that this PCI
+ driver can only work in RTE_IOVA_VA mode.
+
+ When the KNI kernel module is detected, RTE_IOVA_PA mode is preferred as a
+ performance penalty is expected in RTE_IOVA_VA mode.