[PATCH v6 2/7] vfio/type1: Check reserve region conflict and update iova list

[Shameer Kolothum]

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.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.th...@huawei.com>
---
 drivers/vfio/vfio_iommu_type1.c | 90 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 775946d..a0a79e1 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1422,6 +1422,82 @@ 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 (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;
+
+               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;
@@ -1475,6 +1551,7 @@ 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);
 
@@ -1553,6 +1630,13 @@ static int vfio_iommu_type1_attach_group(void 
*iommu_data,
                goto out_detach;
        }
 
+       iommu_get_group_resv_regions(iommu_group, &group_resv_regions);
+
+       if (vfio_iommu_resv_conflict(iommu, &group_resv_regions)) {
+               ret = -EINVAL;
+               goto out_detach;
+       }
+
        /* Get a copy of the current iova list and work on it */
        ret = vfio_iommu_iova_get_copy(iommu, &iova_copy);
        if (ret)
@@ -1563,6 +1647,10 @@ 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);
@@ -1623,6 +1711,7 @@ 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;
 
@@ -1631,6 +1720,7 @@ 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);
-- 
2.7.4