diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 435e84269a28..4037b82c6db0 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -976,7 +976,8 @@ static int verify_bitmap_size(unsigned long npages, unsigned long bitmap_size)
 }
 
 static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
-			     struct vfio_iommu_type1_dma_unmap *unmap)
+			     struct vfio_iommu_type1_dma_unmap *unmap,
+			     unsigned long *bitmap)
 {
 	uint64_t mask;
 	struct vfio_dma *dma, *dma_last = NULL;
@@ -1027,6 +1028,10 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 	 * will be returned if these conditions are not met.  The v2 interface
 	 * will only return success and a size of zero if there were no
 	 * mappings within the range.
+	 *
+	 * When VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP flag is set, unmap request
+	 * must be for single mapping. Multiple mappings with this flag set is
+	 * not supported.
 	 */
 	if (iommu->v2) {
 		dma = vfio_find_dma(iommu, unmap->iova, 1);
@@ -1034,6 +1039,13 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 			ret = -EINVAL;
 			goto unlock;
 		}
+
+		if ((unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) &&
+		    (dma->iova != unmap->iova || dma->size != unmap->size)) {
+			ret = -EINVAL;
+			goto unlock;
+		}
+
 		dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0);
 		if (dma && dma->iova + dma->size != unmap->iova + unmap->size) {
 			ret = -EINVAL;
@@ -1051,6 +1063,11 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 		if (dma->task->mm != current->mm)
 			break;
 
+		if (unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP)
+			vfio_iova_dirty_bitmap(iommu, dma->iova, dma->size,
+					       unmap->bitmap_pgsize,
+					      (unsigned char __user *) bitmap);
+
 		if (!RB_EMPTY_ROOT(&dma->pfn_list)) {
 			struct vfio_iommu_type1_dma_unmap nb_unmap;
 
@@ -1076,6 +1093,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 						    &nb_unmap);
 			goto again;
 		}
+
 		unmapped += dma->size;
 		vfio_remove_dma(iommu, dma);
 	}
@@ -2406,22 +2424,57 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
 
 	} else if (cmd == VFIO_IOMMU_UNMAP_DMA) {
 		struct vfio_iommu_type1_dma_unmap unmap;
-		long ret;
+		unsigned long *bitmap = NULL;
+		long ret, bsize;
 
 		minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size);
 
 		if (copy_from_user(&unmap, (void __user *)arg, minsz))
 			return -EFAULT;
 
-		if (unmap.argsz < minsz || unmap.flags)
+		if (unmap.argsz < minsz ||
+		    unmap.flags & ~VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP)
 			return -EINVAL;
 
-		ret = vfio_dma_do_unmap(iommu, &unmap);
+		if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) {
+			unsigned long pgshift;
+			uint64_t iommu_pgsizes = vfio_pgsize_bitmap(iommu);
+			uint64_t iommu_pgmask =
+				 ((uint64_t)1 << __ffs(iommu_pgsizes)) - 1;
+
+			if (copy_from_user(&unmap, (void __user *)arg,
+					   sizeof(unmap)))
+				return -EFAULT;
+
+			pgshift = __ffs(unmap.bitmap_pgsize);
+
+			if (((unmap.bitmap_pgsize - 1) & iommu_pgmask) !=
+			     (unmap.bitmap_pgsize - 1))
+				return -EINVAL;
+
+			if ((unmap.bitmap_pgsize & iommu_pgsizes) !=
+			     unmap.bitmap_pgsize)
+				return -EINVAL;
+			if (unmap.iova + unmap.size < unmap.iova)
+				return -EINVAL;
+			if (!access_ok((void __user *)unmap.bitmap,
+				       unmap.bitmap_size))
+				return -EINVAL;
+
+			bsize = verify_bitmap_size(unmap.size >> pgshift,
+						   unmap.bitmap_size);
+			if (bsize < 0)
+				return bsize;
+			bitmap = unmap.bitmap;
+		}
+
+		ret = vfio_dma_do_unmap(iommu, &unmap, bitmap);
 		if (ret)
 			return ret;
 
-		return copy_to_user((void __user *)arg, &unmap, minsz) ?
+		ret = copy_to_user((void __user *)arg, &unmap, minsz) ?
 			-EFAULT : 0;
+		return ret;
 	} else if (cmd == VFIO_IOMMU_DIRTY_PAGES) {
 		struct vfio_iommu_type1_dirty_bitmap dirty;
 		uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START |
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 02d555cc7036..12b2094f887e 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -1004,12 +1004,24 @@ struct vfio_iommu_type1_dma_map {
  * field.  No guarantee is made to the user that arbitrary unmaps of iova
  * or size different from those used in the original mapping call will
  * succeed.
+ * VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP should be set to get dirty bitmap
+ * before unmapping IO virtual addresses. When this flag is set, user should
+ * allocate memory to get bitmap, clear the bitmap memory by setting zero and
+ * should set size of allocated memory in bitmap_size field. One bit in bitmap
+ * represents per page , page of user provided page size in 'bitmap_pgsize',
+ * consecutively starting from iova offset. Bit set indicates page at that
+ * offset from iova is dirty. Bitmap of pages in the range of unmapped size is
+ * returned in bitmap.
  */
 struct vfio_iommu_type1_dma_unmap {
 	__u32	argsz;
 	__u32	flags;
+#define VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP (1 << 0)
 	__u64	iova;				/* IO virtual address */
 	__u64	size;				/* Size of mapping (bytes) */
+	__u64        bitmap_pgsize;		/* page size for bitmap */
+	__u64        bitmap_size;               /* in bytes */
+	void __user *bitmap;                    /* one bit per page */
 };
 
 #define VFIO_IOMMU_UNMAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 14)
