On Mon, Aug 18, 2014 at 11:27:01PM +0000, Li, Zhen-Hua wrote: > : [fault reason 01] Present bit in root entry is clear > It appears when iommu initializing in the kdump kernel.
Hmm, do you have an explanation how this can happen? From how I read the code, the kdump kernel disables translation on the IOMMU, then sets a new root entry, and then re-enabled translation. To me it looks like there is no point in time where translation is enabled and the root-entry is clear (present-bit==0). But obviously I am missing something if you see the message above. Btw, have you looked into this patch-set posted earlier this year: https://lkml.org/lkml/2014/4/24/836 It approaches the same problem-space, but also cares about in-flight DMA. Joerg -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/