diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
index 5f63099724..8bb0d2dd29 100644
--- a/hw/cxl/cxl-mailbox-utils.c
+++ b/hw/cxl/cxl-mailbox-utils.c
@@ -649,9 +649,9 @@ static CXLRetCode cmd_firmware_update_get_info(const struct cxl_cmd *cmd,
     } QEMU_PACKED *fw_info;
     QEMU_BUILD_BUG_ON(sizeof(*fw_info) != 0x50);
 
-    if ((cxl_dstate->vmem_size < CXL_CAPACITY_MULTIPLIER) ||
-        (cxl_dstate->pmem_size < CXL_CAPACITY_MULTIPLIER) ||
-        (ct3d->dc.total_capacity < CXL_CAPACITY_MULTIPLIER)) {
+    if (!QEMU_IS_ALIGNED(cxl_dstate->vmem_size, CXL_CAPACITY_MULTIPLIER) ||
+        !QEMU_IS_ALIGNED(cxl_dstate->pmem_size, CXL_CAPACITY_MULTIPLIER) ||
+        !QEMU_IS_ALIGNED(ct3d->dc.total_capacity, CXL_CAPACITY_MULTIPLIER)) {
         return CXL_MBOX_INTERNAL_ERROR;
     }