[RFC/PATCH v3 00/16] KVM/s390: Hugetlbfs enablement

[Janosch Frank <frankja@linux.vnet.ibm.com>]

Since the z10 s390 does support 1M pages, but whereas hugetlbfs
support was added quite fast, KVM always used standard 4k pages for
guest backings.

This patchset adds full support for 1M huge page backings for s390
KVM guests. I.e. we also support VSIE (nested vms) for these guests
and are therefore able to run all combinations of backings for all
layers of guests.

When running a VSIE guest in a huge page backed guest, we need to
split some huge pages to be able to set granular protection. This way
we avoid a prot/unprot cycle if prefixes and VSIE pages containing
level 3 gmap DAT tables share the same segment, as the prefix has to
be accessible at all times and the VSIE page has to be write
protected.

Branch:
git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux.git hlp_vsie
https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux.git/log/?h=hlp_vsie


TODO:
* Cleanups & Documentation
* Regression testing
* Testing large setups
* Testing multi level VSIE
* Split notification does not need to go over all gmaps.
* Fixup commit messages and remove some more reviewed-bys

V3:
	* Moved splitting to the front.
	* Cleanups

V2:
	* Incorporated changes from David's cleanup
	* Now flushing with IDTE_NODAT for protection transfers.
	* Added RRBE huge page handling for g2 -> g3 skey emulation
	* Added documentation for capability
	* Renamed GMAP_ENTRY_* constants
	* Added SEGMENT hardware bits constants
	* Improved some patch descriptions
	* General small improvements
	* Introduced pte_from_pmd function

Accomplished testing:
l2: KVM guest
l3: nested KVM guest

* 1m l2 guests
* VSIE (l3) 4k and 1m guests on 1m l2
* 1m l2 -> l2 migration with 4k/1m l3 guests
* l3 -> l2 migration
* postcopy works every second try, seems to be QEMU or my setup


The initial prototype was started by Dominik Dingel. I had the
pleasure of adding the VSIE part, the protection transfers and the
optimizations. A huge thanks to Christian and Martin who review(ed)
and helped debugging/designing.


Dominik Dingel (2):
  s390/mm: clear huge page storage keys on enable_skey
  s390/mm: hugetlb pages within a gmap can not be freed

Janosch Frank (14):
  s390/mm: make gmap_protect_range more modular
  s390/mm: Abstract gmap notify bit setting
  s390/mm: Introduce gmap_pmdp_xchg
  s390/mm: add gmap PMD invalidation notification
  s390/mm: Add gmap pmd invalidation and clearing
  s390/mm: Add huge page dirty sync support
  s390/mm: Make gmap_read_table EDAT1 compatible
  s390/mm: Make protect_rmap EDAT1 compatible
  s390/mm: Add shadow segment code
  s390/mm: Add VSIE reverse fake case
  s390/mm: Enable gmap huge pmd support
  s390/mm: Add huge pmd storage key handling
  KVM: s390: Add KVM HPAGE capability
  s390/mm: Add gmap lock classes

 Documentation/virtual/kvm/api.txt |   10 +
 arch/s390/include/asm/gmap.h      |   38 +-
 arch/s390/include/asm/pgtable.h   |   19 +-
 arch/s390/kvm/gaccess.c           |   64 +-
 arch/s390/kvm/kvm-s390.c          |   19 +-
 arch/s390/mm/gmap.c               | 1156 +++++++++++++++++++++++++++++++++----
 arch/s390/mm/pageattr.c           |    6 +-
 arch/s390/mm/pgtable.c            |  182 +++++-
 include/uapi/linux/kvm.h          |    1 +
 9 files changed, 1324 insertions(+), 171 deletions(-)

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2.7.4