Re: OMAP and MSM IOMMU driver misbehavior
From: Stepan Moskovchenko
Date: Tue Jan 24 2012 - 14:14:25 EST
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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/