1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c
index 7237cb25f77d..2be59364a49d 100644
--- a/drivers/kvm/x86.c
+++ b/drivers/kvm/x86.c
@@ -1119,6 +1119,20 @@ static int kvm_vm_ioctl_get_nr_mmu_pages(struct kvm *kvm)
         return kvm->n_alloc_mmu_pages;
 }
 
+gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
+{
+        int i;
+        struct kvm_mem_alias *alias;
+
+        for (i = 0; i < kvm->naliases; ++i) {
+                alias = &kvm->aliases[i];
+                if (gfn >= alias->base_gfn
+                    && gfn < alias->base_gfn + alias->npages)
+                        return alias->target_gfn + gfn - alias->base_gfn;
+        }
+        return gfn;
+}
+
 /*
  * Set a new alias region.  Aliases map a portion of physical memory into
  * another portion.  This is useful for memory windows, for example the PC