[dpdk-dev] Why do we need iommu=pt?

[Xie, Huawei]

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Shivapriya Hiremath
> Sent: Monday, October 20, 2014 2:59 PM
> To: dev at dpdk.org
> Subject: [dpdk-dev] Why do we need iommu=pt?
> 
> Hi,
> 
> My question is that if the Poll mode  driver used the DMA kernel interface
> to set up its mappings appropriately, would it still require that iommu=pt
> be set?
> What is the purpose of setting iommu=pt ?
PMD allocates memory though hugetlb file system, and fills the physical address
into the descriptor.
pt is used to pass through iotlb translation. Refer to the below link.
http://lkml.iu.edu/hypermail/linux/kernel/0906.2/02129.html
> 
> Thank you.