On 03/11/2013 12:22 PM, Vivek Goyal wrote: > > So always reserving memory at highest address will break all the cases > which work without iommu and rely on swiotlb. I think first we need > to make sure that kdump works reliably with iommu on, and then try > to move to always reserving memory at higest possible address. >
We should clearly always reserve an swiotlb window, *or*, probably much better, teach the kdump kernel to *make* an swiotlb window (by having a memory buffer in its reserved memory area into which it copies a chunk of low memory, just as we do for the bottom megabyte. If we are already in low memory that buffer becomes the swiotlb window, no copy necessary.) -hpa -- 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/