diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 36900d65386f..a4805d17317d 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -1294,7 +1294,7 @@ restart:
 	 */
 	writel(qi->free_head << shift, iommu->reg + DMAR_IQT_REG);
 
-	while (qi->desc_status[wait_index] != QI_DONE) {
+	while (READ_ONCE(qi->desc_status[wait_index]) != QI_DONE) {
 		/*
 		 * We will leave the interrupts disabled, to prevent interrupt
 		 * context to queue another cmd while a cmd is already submitted