lkml.org 
[lkml]   [2016]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] iommu/dma-iommu: properly respect configured address space size
On Tue, Nov 08, 2016 at 11:37:23AM +0000, Robin Murphy wrote:
> TBH I've been pondering ripping the size stuff out of dma-iommu, as it
> all stems from me originally failing to understand what dma_32bit_pfn is
> actually for.

The point of dma_32bit_pfn is to allocate dma-address below 4G by
default. This is a performance optimization so that even devices capable
of 64bit DMA are using SAC by default instead of DAC.

Since it is the goal to share a dma-iommu implemenation between
architectures, I would rather prefer not to rip this stuff out.


Joerg

\
 
 \ /
  Last update: 2016-11-10 17:00    [W:0.078 / U:1.128 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site