util: Make some iova_tree parameters const

As qemu guidelines:
Unless a pointer is used to modify the pointed-to storage, give it the
"const" attribute.

In the particular case of iova_tree_find it allows to enforce what is
requested by its comment, since the compiler would shout in case of
modifying or freeing the const-qualified returned pointer.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20211013182713.888753-2-eperezma@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 11 insertions, 11 deletions

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 75f0755..33a8af9 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -1105,7 +1105,7 @@ static int vtd_page_walk_one(IOMMUTLBEvent *event, vtd_page_walk_info *info)
         .translated_addr = entry->translated_addr,
         .perm = entry->perm,
     };
-    DMAMap *mapped = iova_tree_find(as->iova_tree, &target);
+    const DMAMap *mapped = iova_tree_find(as->iova_tree, &target);
 
     if (event->type == IOMMU_NOTIFIER_UNMAP && !info->notify_unmap) {
         trace_vtd_page_walk_one_skip_unmap(entry->iova, entry->addr_mask);
diff --git a/include/qemu/iova-tree.h b/include/qemu/iova-tree.h
index b66cf93..8249edd 100644
--- a/include/qemu/iova-tree.h
+++ b/include/qemu/iova-tree.h
@@ -59,7 +59,7 @@ IOVATree *iova_tree_new(void);
  *
  * Return: 0 if succeeded, or <0 if error.
  */
-int iova_tree_insert(IOVATree *tree, DMAMap *map);
+int iova_tree_insert(IOVATree *tree, const DMAMap *map);
 
 /**
  * iova_tree_remove:
@@ -74,7 +74,7 @@ int iova_tree_insert(IOVATree *tree, DMAMap *map);
  *
  * Return: 0 if succeeded, or <0 if error.
  */
-int iova_tree_remove(IOVATree *tree, DMAMap *map);
+int iova_tree_remove(IOVATree *tree, const DMAMap *map);
 
 /**
  * iova_tree_find:
@@ -92,7 +92,7 @@ int iova_tree_remove(IOVATree *tree, DMAMap *map);
  * user is responsible to make sure the pointer is valid (say, no
  * concurrent deletion in progress).
  */
-DMAMap *iova_tree_find(IOVATree *tree, DMAMap *map);
+const DMAMap *iova_tree_find(const IOVATree *tree, const DMAMap *map);
 
 /**
  * iova_tree_find_address:
@@ -105,7 +105,7 @@ DMAMap *iova_tree_find(IOVATree *tree, DMAMap *map);
  *
  * Return: same as iova_tree_find().
  */
-DMAMap *iova_tree_find_address(IOVATree *tree, hwaddr iova);
+const DMAMap *iova_tree_find_address(const IOVATree *tree, hwaddr iova);
 
 /**
  * iova_tree_foreach:
diff --git a/util/iova-tree.c b/util/iova-tree.c
index 7990692..23ea35b 100644
--- a/util/iova-tree.c
+++ b/util/iova-tree.c
@@ -42,14 +42,14 @@ IOVATree *iova_tree_new(void)
     return iova_tree;
 }
 
-DMAMap *iova_tree_find(IOVATree *tree, DMAMap *map)
+const DMAMap *iova_tree_find(const IOVATree *tree, const DMAMap *map)
 {
     return g_tree_lookup(tree->tree, map);
 }
 
-DMAMap *iova_tree_find_address(IOVATree *tree, hwaddr iova)
+const DMAMap *iova_tree_find_address(const IOVATree *tree, hwaddr iova)
 {
-    DMAMap map = { .iova = iova, .size = 0 };
+    const DMAMap map = { .iova = iova, .size = 0 };
 
     return iova_tree_find(tree, &map);
 }
@@ -60,7 +60,7 @@ static inline void iova_tree_insert_internal(GTree *gtree, DMAMap *range)
     g_tree_insert(gtree, range, range);
 }
 
-int iova_tree_insert(IOVATree *tree, DMAMap *map)
+int iova_tree_insert(IOVATree *tree, const DMAMap *map)
 {
     DMAMap *new;
 
@@ -96,9 +96,9 @@ void iova_tree_foreach(IOVATree *tree, iova_tree_iterator iterator)
     g_tree_foreach(tree->tree, iova_tree_traverse, iterator);
 }
 
-int iova_tree_remove(IOVATree *tree, DMAMap *map)
+int iova_tree_remove(IOVATree *tree, const DMAMap *map)
 {
-    DMAMap *overlap;
+    const DMAMap *overlap;
 
     while ((overlap = iova_tree_find(tree, map))) {
         g_tree_remove(tree->tree, overlap);