On 9/13/2012 9:27 AM, Hada, Craig M wrote:
This patch sets the coherent DMA mask to 64-bit after the be2net driver has
been acknowledged that the system is 64-bit DMA capable. The coherent DMA mask
is examined by the Intel IOMMU driver to determine whether to allow pass
through context mapping for all devices. With this patch, the be2net driver
combined with be2net compatible hardware provides comparable performance to the
case where vt-d is disabled. The main use case for this change is to decrease
the time necessary to copy virtual machine memory during KVM live migration
instantiations.
This patch was tested on a system that enables the IOMMU in non-coherent mode.
Two DMA remapper issues were encountered and both are in the Intel IOMMU driver
with the following patches submitted upstream but not yet commited.
Patch 1 - DMAR:[fault reason 02] Present bit in context entry is clear
https://lkml.org/lkml/2012/6/15/20
My apologies for posting a truncated link for the above. The correct link is
https://lkml.org/lkml/2012/6/15/204
-Craig
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