Messages in this thread | | | From | Roland Dreier <> | Date | Fri, 11 Nov 2011 16:46:45 -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 4:37 PM, David Woodhouse <dwmw2@infradead.org> wrote: > This brain-damage only affects the first chipsets > from before we worked out that cache incoherency was a *really* f*cking > stupid idea, doesn't it?
As we talked about at KS, I have some Westmere EP (ie latest and greatest server platform) systems where the BIOS exposes an option that allows choosing VT-d coherency on or off, and defaults it to "off".
What is the "official" Intel line on coherency with Westmere and Tylersburg -- because as I also mentioned, I was seeing some problems with VT-d and the default "coherency off" setting that looked like the IOMMU HW is getting stale PTEs (ie a missing or not working cache flush).
- R.
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