[PATCH v8 2/6] vfio/type1: Check reserved region conflict and update iova list

[Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>]

This retrieves the reserved regions associated with dev group and
checks for conflicts with any existing dma mappings. Also update
the iova list excluding the reserved regions.

Reserved regions with type IOMMU_RESV_DIRECT_RELAXABLE are
excluded from above checks as they are considered as directly
mapped regions which are known to be relaxable.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
---
v7-->v8
 -Added check for iommu_get_group_resv_regions() error ret.

---
 drivers/vfio/vfio_iommu_type1.c | 98 +++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 6a69652b406b..a3c9794ccf83 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1496,6 +1496,88 @@ static int vfio_iommu_aper_resize(struct list_head *iova,
 	return 0;
 }
 
+/*
+ * Check reserved region conflicts with existing dma mappings
+ */
+static bool vfio_iommu_resv_conflict(struct vfio_iommu *iommu,
+				     struct list_head *resv_regions)
+{
+	struct iommu_resv_region *region;
+
+	/* Check for conflict with existing dma mappings */
+	list_for_each_entry(region, resv_regions, list) {
+		if (region->type == IOMMU_RESV_DIRECT_RELAXABLE)
+			continue;
+
+		if (vfio_find_dma(iommu, region->start, region->length))
+			return true;
+	}
+
+	return false;
+}
+
+/*
+ * Check iova region overlap with  reserved regions and
+ * exclude them from the iommu iova range
+ */
+static int vfio_iommu_resv_exclude(struct list_head *iova,
+				   struct list_head *resv_regions)
+{
+	struct iommu_resv_region *resv;
+	struct vfio_iova *n, *next;
+
+	list_for_each_entry(resv, resv_regions, list) {
+		phys_addr_t start, end;
+
+		if (resv->type == IOMMU_RESV_DIRECT_RELAXABLE)
+			continue;
+
+		start = resv->start;
+		end = resv->start + resv->length - 1;
+
+		list_for_each_entry_safe(n, next, iova, list) {
+			int ret = 0;
+
+			/* No overlap */
+			if (start > n->end || end < n->start)
+				continue;
+			/*
+			 * Insert a new node if current node overlaps with the
+			 * reserve region to exlude that from valid iova range.
+			 * Note that, new node is inserted before the current
+			 * node and finally the current node is deleted keeping
+			 * the list updated and sorted.
+			 */
+			if (start > n->start)
+				ret = vfio_iommu_iova_insert(&n->list, n->start,
+							     start - 1);
+			if (!ret && end < n->end)
+				ret = vfio_iommu_iova_insert(&n->list, end + 1,
+							     n->end);
+			if (ret)
+				return ret;
+
+			list_del(&n->list);
+			kfree(n);
+		}
+	}
+
+	if (list_empty(iova))
+		return -EINVAL;
+
+	return 0;
+}
+
+static void vfio_iommu_resv_free(struct list_head *resv_regions)
+{
+	struct iommu_resv_region *n, *next;
+
+	list_for_each_entry_safe(n, next, resv_regions, list) {
+		list_del(&n->list);
+		kfree(n);
+	}
+}
+
 static void vfio_iommu_iova_free(struct list_head *iova)
 {
 	struct vfio_iova *n, *next;
@@ -1547,6 +1629,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 	phys_addr_t resv_msi_base;
 	struct iommu_domain_geometry geo;
 	LIST_HEAD(iova_copy);
+	LIST_HEAD(group_resv_regions);
 
 	mutex_lock(&iommu->lock);
 
@@ -1632,6 +1715,15 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 		goto out_detach;
 	}
 
+	ret = iommu_get_group_resv_regions(iommu_group, &group_resv_regions);
+	if (ret)
+		goto out_detach;
+
+	if (vfio_iommu_resv_conflict(iommu, &group_resv_regions)) {
+		ret = -EINVAL;
+		goto out_detach;
+	}
+
 	/*
 	 * We don't want to work on the original iova list as the list
 	 * gets modified and in case of failure we have to retain the
@@ -1646,6 +1738,10 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 	if (ret)
 		goto out_detach;
 
+	ret = vfio_iommu_resv_exclude(&iova_copy, &group_resv_regions);
+	if (ret)
+		goto out_detach;
+
 	resv_msi = vfio_iommu_has_sw_msi(iommu_group, &resv_msi_base);
 
 	INIT_LIST_HEAD(&domain->group_list);
@@ -1706,6 +1802,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 	/* Delete the old one and insert new iova list */
 	vfio_iommu_iova_insert_copy(iommu, &iova_copy);
 	mutex_unlock(&iommu->lock);
+	vfio_iommu_resv_free(&group_resv_regions);
 
 	return 0;
 
@@ -1714,6 +1811,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 out_domain:
 	iommu_domain_free(domain->domain);
 	vfio_iommu_iova_free(&iova_copy);
+	vfio_iommu_resv_free(&group_resv_regions);
 out_free:
 	kfree(domain);
 	kfree(group);
-- 
2.17.1