lkml.org 
[lkml]   [2012]   [Jan]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: OMAP and MSM IOMMU driver misbehavior
On 1/23/2012 6:03 AM, Joerg Roedel wrote:
> Hi,
>
> while reviewing another IOMMU driver again I came across a problem in
> the IOMMU drivers for OMAP and MSM platforms. In both drivers the
> 'domain_destroy with devices attached' case isn't handled correctly.
>
> OMAP driver seems not to track the devices attached to a domain at all.
> So when a domain is destroyed it can happen that the hardware still
> references old (and already freed) page-table pointers.
>
> MSM tracks devices in a domain, but does not automatically remove the
> devices from a domain that is about to be destroyed.
>
> Please tell me when I mis-read the code, otherwise please fix this in
> your drivers so that we can get consistent behavior for IOMMU-API
> users :-)
>
> Thanks,
>
> Joerg

Hello

I believe your analysis is correct, and it is a legitimate problem. The
driver does keep a list of devices attached to a domain, so it should
not be too hard to detach them. However, I have been quite occupied with
other things lately, but I can try to get to it when I have some free
time. Calling detach_dev on each element is what needs to happen in
theory, but I feel like the main detach_dev code will need to be broken
out to handle the locking properly. Still, it does not sound
particularly difficult.

Steve



\
 
 \ /
  Last update: 2012-01-24 20:17    [from the cache]
©2003-2011 Jasper Spaans