On Thu, Nov 10, 2011 at 10:35:34PM +0800, cody wrote: > Yes I totally agree page-size is not required for unmap operations > and should not be added as parameter to map/unmap operations. I am > not saying the unmap operation, but the IOTLB flush operation. My > point is we also may also need to add similar logic in IOTLB flush > code (such as in Intel IOMMU dirver) to grantee that when issuing > IOTLB flush command for large page, we will still meet the hardware > limitation of flushing large page. Seems for Intel IOMMU the only > limitation is the mask value (indicating number of 4k-pages) cannot > be smaller than the value to cover large page, and seems current > Intel IOMMU driver code has covered this case well. I am not > familiar with how AMD IOMMU issues IOTLB flush command, it should be > able to handle this large page case too. So at this moment, this > patch should not have any issues :) The map-operation actually takes a size, as it should. The idea is to change this function to a map_page interface which takes a page-size parameter, but thats another story. The IOTLB flushing is not exposed by the IOMMU-API anyway. To whatever is necessary to do that, it is the business of the IOMMU driver. So in the unmap-path the driver finds out the page-size to unmap and can immediatly flush the IOTLB for that page. Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
