diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index f54408355d1dc7..cd819725193bbd 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -666,14 +666,33 @@ static int get_user_mapping_size(struct kvm *kvm, u64 addr) CONFIG_PGTABLE_LEVELS), .mm_ops = &kvm_user_mm_ops, }; + unsigned long flags; kvm_pte_t pte = 0; /* Keep GCC quiet... */ u32 level = ~0; int ret; + /* + * Disable IRQs so that we hazard against a concurrent + * teardown of the userspace page tables (which relies on + * IPI-ing threads). + */ + local_irq_save(flags); ret = kvm_pgtable_get_leaf(&pgt, addr, &pte, &level); - VM_BUG_ON(ret); - VM_BUG_ON(level >= KVM_PGTABLE_MAX_LEVELS); - VM_BUG_ON(!(pte & PTE_VALID)); + local_irq_restore(flags); + + if (ret) + return ret; + + /* + * Not seeing an error, but not updating level? Something went + * deeply wrong... + */ + if (WARN_ON(level >= KVM_PGTABLE_MAX_LEVELS)) + return -EFAULT; + + /* Oops, the userspace PTs are gone... Replay the fault */ + if (!kvm_pte_valid(pte)) + return -EAGAIN; return BIT(ARM64_HW_PGTABLE_LEVEL_SHIFT(level)); } @@ -1079,7 +1098,7 @@ static bool fault_supports_stage2_huge_mapping(struct kvm_memory_slot *memslot, * * Returns the size of the mapping. */ -static unsigned long +static long transparent_hugepage_adjust(struct kvm *kvm, struct kvm_memory_slot *memslot, unsigned long hva, kvm_pfn_t *pfnp, phys_addr_t *ipap) @@ -1091,8 +1110,15 @@ transparent_hugepage_adjust(struct kvm *kvm, struct kvm_memory_slot *memslot, * sure that the HVA and IPA are sufficiently aligned and that the * block map is contained within the memslot. */ - if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE) && - get_user_mapping_size(kvm, hva) >= PMD_SIZE) { + if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE)) { + int sz = get_user_mapping_size(kvm, hva); + + if (sz < 0) + return sz; + + if (sz < PMD_SIZE) + return PAGE_SIZE; + /* * The address we faulted on is backed by a transparent huge * page. However, because we map the compound huge page and @@ -1203,7 +1229,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, kvm_pfn_t pfn; bool logging_active = memslot_is_logging(memslot); unsigned long fault_level = kvm_vcpu_trap_get_fault_level(vcpu); - unsigned long vma_pagesize, fault_granule; + long vma_pagesize, fault_granule; enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R; struct kvm_pgtable *pgt; @@ -1344,6 +1370,11 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, vma_pagesize = transparent_hugepage_adjust(kvm, memslot, hva, &pfn, &fault_ipa); + + if (vma_pagesize < 0) { + ret = vma_pagesize; + goto out_unlock; + } } if (fault_status != ESR_ELx_FSC_PERM && !device && kvm_has_mte(kvm)) {