[dpdk-dev] [PATCH] eal: add option to force IOVA as PA mode

Chas Williams 3chas3 at gmail.com
Sun Dec 3 01:25:06 CET 2017

On Fri, Dec 1, 2017 at 12:48 AM, Hemant Agrawal <hemant.agrawal at nxp.com>

> On 11/30/2017 8:27 AM, Chas Williams wrote:
>> From: Chas Williams <chas3 at att.com>
>> The IOMMU in some machines report that they can only support
>> limited widths.  IOVA virtual addresses may exceed this width
>> making the use of IOVA virtual addresses difficult.  The option
>> CONFIG_RTE_LIBRTE_USE_PHYS_IOVA can used to force IOVA physical
>> address usage.
> Is it possible to dynamically detect the machine limitation in bus iova
> code instead of compile time option?
Yes, I think you can examine the "cap" of the IOMMU group in /sys and
determine the bit width.  I will have to check on that.

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