On Wednesday 11 October 2017 11:01 AM, Tan, Jianfeng wrote: > > > On 10/11/2017 12:43 PM, santosh wrote: >> On Wednesday 11 October 2017 07:17 AM, Tan, Jianfeng wrote: >>> Hi, >>> >>> Nice patch series. But I still have a small question about below flag. >>> >>> >>> On 10/6/2017 7:03 PM, Santosh Shukla wrote: >>>> Get iommu class of PCI device on the bus and returns preferred iova >>>> mapping mode for that bus. >>>> >>>> Patch also introduces RTE_PCI_DRV_IOVA_AS_VA drv flag. >>>> Flag used when driver needs to operate in iova=va mode. >>>> >>> Does this flag indicate a must to use VA as IOVA, or a nice-to-have one? In >>> detail, above commit log says, "needs to operate in iova=va mode", but the >>> comment in the patch indicates this flag means "driver supports IOVA as VA". >>> >>> If it's the latter case, I would suppose all drivers support to use VA as >>> IOVA, if the NICs are binded to vfio-pci (iommu mode). Please correct me if >>> I'm wrong. >>> >> - Any iommu backed pmd could choose to use this flag. > > But if this is characterized by assumption for all PMDs, why do we trouble to > introduce this flag. > to hint bus layer about iova=va mapping choice for _this_ driver and default is iova=pa.
Thanks.
