On 4/10/2024 3:03 AM, Eugenio Pérez wrote:
IOVA tree is also used to track the mappings of virtio-net shadow
virtqueue. This mappings may not match with the GPA->HVA ones.
This causes a problem when overlapped regions (different GPA but same
translated HVA) exists in the tree, as looking them by HVA will return
them twice. To solve this, create an id member so we can assign unique
identifiers (GPA) to the maps.
Signed-off-by: Eugenio Pérez <epere...@redhat.com>
---
include/qemu/iova-tree.h | 5 +++--
util/iova-tree.c | 3 ++-
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/include/qemu/iova-tree.h b/include/qemu/iova-tree.h
index 2a10a7052e..34ee230e7d 100644
--- a/include/qemu/iova-tree.h
+++ b/include/qemu/iova-tree.h
@@ -36,6 +36,7 @@ typedef struct DMAMap {
hwaddr iova;
hwaddr translated_addr;
hwaddr size; /* Inclusive */
+ uint64_t id;
IOMMUAccessFlags perm;
} QEMU_PACKED DMAMap;
typedef gboolean (*iova_tree_iterator)(DMAMap *map);
@@ -100,8 +101,8 @@ const DMAMap *iova_tree_find(const IOVATree *tree, const
DMAMap *map);
* @map: the mapping to search
*
* Search for a mapping in the iova tree that translated_addr overlaps with
the
- * mapping range specified. Only the first found mapping will be
- * returned.
+ * mapping range specified and map->id is equal. Only the first found
+ * mapping will be returned.
*
* Return: DMAMap pointer if found, or NULL if not found. Note that
* the returned DMAMap pointer is maintained internally. User should
diff --git a/util/iova-tree.c b/util/iova-tree.c
index 536789797e..0863e0a3b8 100644
--- a/util/iova-tree.c
+++ b/util/iova-tree.c
@@ -97,7 +97,8 @@ static gboolean iova_tree_find_address_iterator(gpointer key,
gpointer value,
needle = args->needle;
if (map->translated_addr + map->size < needle->translated_addr ||
- needle->translated_addr + needle->size < map->translated_addr) {
+ needle->translated_addr + needle->size < map->translated_addr ||
+ needle->id != map->id) {
It looks this iterator can also be invoked by SVQ from
vhost_svq_translate_addr() -> iova_tree_find_iova(), where guest GPA
space will be searched on without passing in the ID (GPA), and exact
match for the same GPA range is not actually needed unlike the mapping
removal case. Could we create an API variant, for the SVQ lookup case
specifically? Or alternatively, add a special flag, say skip_id_match to
DMAMap, and the id match check may look like below:
(!needle->skip_id_match && needle->id != map->id)
I think vhost_svq_translate_addr() could just call the API variant or
pass DMAmap with skip_id_match set to true to svq_iova_tree_find_iova().
Thanks,
-Siwei
return false;
}
