lkml.org 
[lkml]   [2015]   [Nov]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v3 0/3] virtio DMA API core stuff
From
Date
On 11/22/2015 05:54 PM, David Woodhouse wrote:
> On Sun, 2015-11-22 at 15:06 +0200, Marcel Apfelbaum wrote:
>>
>>
>> I tried to generate a DMAR table that excludes some devices from
>> IOMMU translation, however it does not help.
>>
>> The reason is, as far as I understand, that Linux kernel does
>> not allow any device being outside an IOMMU scope if the
>> iommu kernel option is activated.
>>
>> Does anybody know if it is "by design" or is simply an uncommon
>> configuration?
>> (some devices in an IOMMU scope, while others outside *any* IOMMU
>> scope)
>
> That's a kernel bug in the way it handles per-device DMA operations. Or
> more to the point, in the way it doesn't — the non-translated devices
> end up being pointed to the intel_dma_ops despite the fact they
> shouldn't be. I'm working on that...
>

Hi David,
Thank you for the fast response.

Sadly I am not familiar with the DMA/IOMMU code to contribute
with a sane idea, but I'll gladly test it.
If you lack the time and have an idea to share, I can give it a try though.

Thanks,
Marcel




\
 
 \ /
  Last update: 2015-11-22 18:21    [W:0.188 / U:0.184 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site