1 files changed, 7 insertions, 1 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3caf8162eb6b..e4d358195e54 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -784,13 +784,19 @@ int __kvm_set_memory_region(struct kvm *kvm,
 
         r = -ENOMEM;
 
-        /* Allocate if a slot is being created */
+        /*
+         * Allocate if a slot is being created.  If modifying a slot,
+         * the userspace_addr cannot change.
+         */
         if (!old.npages) {
                 new.user_alloc = user_alloc;
                 new.userspace_addr = mem->userspace_addr;
 
                 if (kvm_arch_create_memslot(&new, npages))
                         goto out_free;
+        } else if (npages && mem->userspace_addr != old.userspace_addr) {
+                r = -EINVAL;
+                goto out_free;
         }
 
         /* Allocate page dirty bitmap if needed */