When a memslot is removed, all ptes that mapped the slot are cleared or even deallocated. If this happens while the system is in migration mode, and if cmma-dirty pages are removed, the cmma-dirty counter will not reflect reality. Fix by appropriately decrementing the cmma-dirty counter when removing a memslot. Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Signed-off-by: Claudio Imbrenda --- arch/s390/kvm/kvm-s390.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 512c81eee068..2ac3a9ac4698 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -5792,11 +5792,19 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, return 0; } +static long cmma_d_count_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_walk *walk) +{ + if (pgste_of(ptep)->cmma_d) + atomic64_dec(walk->priv); + return 0; +} + void kvm_arch_commit_memory_region(struct kvm *kvm, struct kvm_memory_slot *old, const struct kvm_memory_slot *new, enum kvm_mr_change change) { + const struct dat_walk_ops ops = { .pte_entry = cmma_d_count_pte, }; struct kvm_s390_mmu_cache *mc = NULL; int rc = 0; @@ -5810,6 +5818,12 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, } scoped_guard(write_lock, &kvm->mmu_lock) { + if (kvm->arch.migration_mode && kvm->arch.use_cmma) { + _dat_walk_gfn_range(old->base_gfn, old->base_gfn + old->npages, + kvm->arch.gmap->asce, &ops, DAT_WALK_IGN_HOLES, + &kvm->arch.cmma_dirty_pages); + } + switch (change) { case KVM_MR_DELETE: rc = dat_delete_slot(mc, kvm->arch.gmap->asce, old->base_gfn, old->npages); -- 2.55.0