4 files changed, 74 insertions, 0 deletions

diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index f867060035ec..63e0ecc04901 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -52,6 +52,7 @@ int create_hyp_io_mappings(void *from, void *to, phys_addr_t);
 void free_boot_hyp_pgd(void);
 void free_hyp_pgds(void);
 
+void stage2_unmap_vm(struct kvm *kvm);
 int kvm_alloc_stage2_pgd(struct kvm *kvm);
 void kvm_free_stage2_pgd(struct kvm *kvm);
 int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 4043769583e7..da87c07d8577 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -701,6 +701,13 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu,
         if (ret)
                 return ret;
 
+        /*
+         * Ensure a rebooted VM will fault in RAM pages and detect if the
+         * guest MMU is turned off and flush the caches as needed.
+         */
+        if (vcpu->arch.has_run_once)
+                stage2_unmap_vm(vcpu->kvm);
+
         vcpu_reset_hcr(vcpu);
 
         /*
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index f2a9874ff5cb..3756dd3e85c2 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -611,6 +611,71 @@ static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size)
         unmap_range(kvm, kvm->arch.pgd, start, size);
 }
 
+static void stage2_unmap_memslot(struct kvm *kvm,
+                                 struct kvm_memory_slot *memslot)
+{
+        hva_t hva = memslot->userspace_addr;
+        phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
+        phys_addr_t size = PAGE_SIZE * memslot->npages;
+        hva_t reg_end = hva + size;
+
+        /*
+         * A memory region could potentially cover multiple VMAs, and any holes
+         * between them, so iterate over all of them to find out if we should
+         * unmap any of them.
+         *
+         *     +--------------------------------------------+
+         * +---------------+----------------+   +----------------+
+         * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
+         * +---------------+----------------+   +----------------+
+         *     |               memory region                |
+         *     +--------------------------------------------+
+         */
+        do {
+                struct vm_area_struct *vma = find_vma(current->mm, hva);
+                hva_t vm_start, vm_end;
+
+                if (!vma || vma->vm_start >= reg_end)
+                        break;
+
+                /*
+                 * Take the intersection of this VMA with the memory region
+                 */
+                vm_start = max(hva, vma->vm_start);
+                vm_end = min(reg_end, vma->vm_end);
+
+                if (!(vma->vm_flags & VM_PFNMAP)) {
+                        gpa_t gpa = addr + (vm_start - memslot->userspace_addr);
+                        unmap_stage2_range(kvm, gpa, vm_end - vm_start);
+                }
+                hva = vm_end;
+        } while (hva < reg_end);
+}
+
+/**
+ * stage2_unmap_vm - Unmap Stage-2 RAM mappings
+ * @kvm: The struct kvm pointer
+ *
+ * Go through the memregions and unmap any reguler RAM
+ * backing memory already mapped to the VM.
+ */
+void stage2_unmap_vm(struct kvm *kvm)
+{
+        struct kvm_memslots *slots;
+        struct kvm_memory_slot *memslot;
+        int idx;
+
+        idx = srcu_read_lock(&kvm->srcu);
+        spin_lock(&kvm->mmu_lock);
+
+        slots = kvm_memslots(kvm);
+        kvm_for_each_memslot(memslot, slots)
+                stage2_unmap_memslot(kvm, memslot);
+
+        spin_unlock(&kvm->mmu_lock);
+        srcu_read_unlock(&kvm->srcu, idx);
+}
+
 /**
  * kvm_free_stage2_pgd - free all stage-2 tables
  * @kvm:        The KVM struct pointer for the VM.
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 123b521a9908..14a74f136272 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -83,6 +83,7 @@ int create_hyp_io_mappings(void *from, void *to, phys_addr_t);
 void free_boot_hyp_pgd(void);
 void free_hyp_pgds(void);
 
+void stage2_unmap_vm(struct kvm *kvm);
 int kvm_alloc_stage2_pgd(struct kvm *kvm);
 void kvm_free_stage2_pgd(struct kvm *kvm);
 int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,