Pull IOMMU SVM fixes from David Woodhouse:
 "Minor register size and interrupt acknowledgement fixes which only
  showed up in testing on newer hardware, but mostly a fix to the MM
  refcount handling to prevent a recursive refcount issue when mmap() is
  used on the file descriptor associated with a bound PASID"

* tag 'for-linus-20160216' of git://git.infradead.org/intel-iommu:
  iommu/vt-d: Clear PPR bit to ensure we get more page request interrupts
  iommu/vt-d: Fix 64-bit accesses to 32-bit DMAR_GSTS_REG
  iommu/vt-d: Fix mm refcounting to hold mm_count not mm_users