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. TODO: * Cleanups & Documentation * Refactoring to get rid of a lot of indents * Storage key support for split pages * Regression testing * Testing large setups * Testing multi level VSIE 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: hugetlb pages within a gmap can not be freed s390/mm: clear huge page storage keys on enable_skey Janosch Frank (20): s390/mm: make gmap_protect_range more modular s390/mm: Abstract gmap notify bit setting s390/mm: add gmap PMD invalidation notification s390/mm: Add gmap pmd invalidation and clearing s390/mm: Introduce gmap_pmdp_xchg RFC: s390/mm: Transfer guest pmd protection to host s390/mm: Add huge page dirty sync support s390/mm: Add huge pmd storage key handling s390/mm: Remove superfluous parameter s390/mm: Add gmap_protect_large read protection support s390/mm: Make gmap_read_table EDAT1 compatible s390/mm: Make protect_rmap EDAT1 compatible s390/mm: GMAP read table extensions s390/mm: Add shadow segment code s390/mm: Add VSIE reverse fake case s390/mm: Remove gmap_pte_op_walk s390/mm: Split huge pages if granular protection is needed s390/mm: Enable gmap huge pmd support KVM: s390: Add KVM HPAGE capability RFC: s390/mm: Add gmap lock classes arch/s390/include/asm/gmap.h | 39 +- arch/s390/include/asm/pgtable.h | 12 +- arch/s390/kvm/gaccess.c | 64 +- arch/s390/kvm/kvm-s390.c | 18 +- arch/s390/mm/fault.c | 10 +- arch/s390/mm/gmap.c | 1296 +++++++++++++++++++++++++++++++++++---- arch/s390/mm/pageattr.c | 6 +- arch/s390/mm/pgtable.c | 143 ++++- include/uapi/linux/kvm.h | 1 + 9 files changed, 1421 insertions(+), 168 deletions(-) -- 2.7.4
