diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
index 4944f0faf9..d431834030 100644
--- a/hw/mem/pc-dimm.c
+++ b/hw/mem/pc-dimm.c
@@ -146,6 +146,9 @@ uint64_t pc_dimm_get_free_addr(uint64_t address_space_start,
     uint64_t new_addr, ret = 0;
     uint64_t address_space_end = address_space_start + address_space_size;
 
+    g_assert(QEMU_ALIGN_UP(address_space_start, align) == address_space_start);
+    g_assert(QEMU_ALIGN_UP(address_space_size, align) == address_space_size);
+
     if (!address_space_size) {
         error_setg(errp, "memory hotplug is not enabled, "
                          "please add maxmem option");
@@ -189,7 +192,7 @@ uint64_t pc_dimm_get_free_addr(uint64_t address_space_start,
                 error_setg(errp, "address range conflicts with '%s'", d->id);
                 goto out;
             }
-            new_addr = dimm->addr + dimm_size;
+            new_addr = QEMU_ALIGN_UP(dimm->addr + dimm_size, align);
         }
     }
     ret = new_addr;