Comment 64 for bug 1541902

Reviewing the diff, the changes are all well-isolated to hw/ppc + target-ppc, with the following exceptions:
 - trace-events
 - a few additions to generic headers
 - 98295803b5a7929232fd92ecf17137c991273678, fc8865d5c3e733c7b03070017778b31de22c329f, 94582d197efb7030f5d0dccab6165c28fb62d5b5 and 561e77f740999600449223c912126a575c7ec3ce, which make changes to hw/vfio/common.c and memory.c which appear to be reasonably self-contained changes
 - b6dc0429cb690572984e34aa6bfe557beed82282, which makes intel iommu handling more strict; this doesn't appear to be an actual prerequisite for the rest of the ppc64el patches, but it also appears to be harmless in the sense that it will cause earlier failure in the case of driver errors
 - changes to hw/vfio/common.c in 330619403e536e0e31671ae5bcd9f9921e73d9c9 which are spapr-specific (and therefore ppc-specific in practice)

This looks like a reasonably safe change, given the testing that's been done in the ppa.

As part of this FFe, these patches should be re-tested on top of 2.6.1 (LP: #1617055).