Messages in this thread | | | From | Roland Dreier <> | Date | Fri, 11 Nov 2011 17:30:01 -0800 | Subject | Re: [PATCH] intel-iommu: Default to non-coherent for domains unattached to iommus |
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On Fri, Nov 11, 2011 at 5:08 PM, Chris Wright <chrisw@sous-sol.org> wrote: >> I would be more inclined to suspect that there's some >> chipset buffering that we aren't correctly flushing (which might in >> itself be a hardware issue, since the way to flush the cache is supposed >> to be well-defined). > > Roland, have you tried switching BIOS to Coherency On and can do you > ever see stale PTEs?
Yeah, the problems go away if I turn on coherency.
More details here: https://lkml.org/lkml/2011/10/11/412
(and after that email, I let the box run long enough that I'm pretty sure turning VT-d coherency on does fix things)
I'd love to fix this but not sure how much I can contribute beyond tests (I don't see anything wrong in the VT-d cache flushing code in the kernel, and I did look for a while).
- R.
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