FEAT_HDBSS speeds up guest memory dirty tracking by avoiding a page fault and saving the entry in a tracking structure. That may be a problem when we have guest memory backed by hugepages or transparent huge pages, as it's not possible to do on-demand hugepage splitting, relying only on eager hugepage splitting. So, at stage2 initialization, enable eager hugepage splitting with chunk = PAGE_SIZE if the system supports HDBSS. Signed-off-by: Leonardo Bras --- arch/arm64/kvm/mmu.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index d089c107d9b7..42c734423253 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -993,22 +993,26 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t mmu->last_vcpu_ran = alloc_percpu(typeof(*mmu->last_vcpu_ran)); if (!mmu->last_vcpu_ran) { err = -ENOMEM; goto out_destroy_pgtable; } for_each_possible_cpu(cpu) *per_cpu_ptr(mmu->last_vcpu_ran, cpu) = -1; - /* The eager page splitting is disabled by default */ - mmu->split_page_chunk_size = KVM_ARM_EAGER_SPLIT_CHUNK_SIZE_DEFAULT; + /* The eager page splitting is disabled by default if system has no HDBSS */ + if (system_supports_hacdbs()) + mmu->split_page_chunk_size = PAGE_SIZE; + else + mmu->split_page_chunk_size = KVM_ARM_EAGER_SPLIT_CHUNK_SIZE_DEFAULT; + mmu->split_page_cache.gfp_zero = __GFP_ZERO; mmu->pgd_phys = __pa(pgt->pgd); if (kvm_is_nested_s2_mmu(kvm, mmu)) kvm_init_nested_s2_mmu(mmu); return 0; out_destroy_pgtable: -- 2.54.0