1 files changed, 15 insertions, 5 deletions

diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index cb924c6d56a6..f2a9874ff5cb 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -919,7 +919,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
         if (!hugetlb && !force_pte)
                 hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa);
 
-        fault_ipa_uncached = false;
+        fault_ipa_uncached = memslot->flags & KVM_MEMSLOT_INCOHERENT;
 
         if (hugetlb) {
                 pmd_t new_pmd = pfn_pmd(pfn, mem_type);
@@ -1298,11 +1298,12 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
                 hva = vm_end;
         } while (hva < reg_end);
 
-        if (ret) {
-                spin_lock(&kvm->mmu_lock);
+        spin_lock(&kvm->mmu_lock);
+        if (ret)
                 unmap_stage2_range(kvm, mem->guest_phys_addr, mem->memory_size);
-                spin_unlock(&kvm->mmu_lock);
-        }
+        else
+                stage2_flush_memslot(kvm, memslot);
+        spin_unlock(&kvm->mmu_lock);
         return ret;
 }
 
@@ -1314,6 +1315,15 @@ void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
 int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
                             unsigned long npages)
 {
+        /*
+         * Readonly memslots are not incoherent with the caches by definition,
+         * but in practice, they are used mostly to emulate ROMs or NOR flashes
+         * that the guest may consider devices and hence map as uncached.
+         * To prevent incoherency issues in these cases, tag all readonly
+         * regions as incoherent.
+         */
+        if (slot->flags & KVM_MEM_READONLY)
+                slot->flags |= KVM_MEMSLOT_INCOHERENT;
         return 0;
 }