vfio/type1: implement unmap all

Implement VFIO_DMA_UNMAP_FLAG_ALL.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/vfio_iommu_type1.c

@@ -1078,6 +1078,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 	unsigned long pgshift;
 	dma_addr_t iova = unmap->iova;
 	unsigned long size = unmap->size;
+	bool unmap_all = unmap->flags & VFIO_DMA_UNMAP_FLAG_ALL;
 
 	mutex_lock(&iommu->lock);
 
@@ -1087,8 +1088,13 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 	if (iova & (pgsize - 1))
 		goto unlock;
 
-	if (!size || size & (pgsize - 1))
+	if (unmap_all) {
+		if (iova || size)
+			goto unlock;
+		size = SIZE_MAX;
+	} else if (!size || size & (pgsize - 1)) {
 		goto unlock;
+	}
 
 	if (iova + size - 1 < iova || size > SIZE_MAX)
 		goto unlock;
@@ -1132,7 +1138,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 	 * will only return success and a size of zero if there were no
 	 * mappings within the range.
 	 */
-	if (iommu->v2) {
+	if (iommu->v2 && !unmap_all) {
 		dma = vfio_find_dma(iommu, iova, 1);
 		if (dma && dma->iova != iova)
 			goto unlock;
@@ -2509,6 +2515,7 @@ static int vfio_iommu_type1_check_extension(struct vfio_iommu *iommu,
 	case VFIO_TYPE1_IOMMU:
 	case VFIO_TYPE1v2_IOMMU:
 	case VFIO_TYPE1_NESTING_IOMMU:
+	case VFIO_UNMAP_ALL:
 		return 1;
 	case VFIO_DMA_CC_IOMMU:
 		if (!iommu)
@@ -2698,6 +2705,8 @@ static int vfio_iommu_type1_unmap_dma(struct vfio_iommu *iommu,
 {
 	struct vfio_iommu_type1_dma_unmap unmap;
 	struct vfio_bitmap bitmap = { 0 };
+	uint32_t mask = VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP |
+			VFIO_DMA_UNMAP_FLAG_ALL;
 	unsigned long minsz;
 	int ret;
 
@@ -2706,8 +2715,11 @@ static int vfio_iommu_type1_unmap_dma(struct vfio_iommu *iommu,
 	if (copy_from_user(&unmap, (void __user *)arg, minsz))
 		return -EFAULT;
 
-	if (unmap.argsz < minsz ||
-	    unmap.flags & ~VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP)
+	if (unmap.argsz < minsz || unmap.flags & ~mask)
+		return -EINVAL;
+
+	if ((unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) &&
+	    (unmap.flags & VFIO_DMA_UNMAP_FLAG_ALL))
 		return -EINVAL;
 
 	if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) {