In our RB-tree we get prepared to insert slots of different types
(USER and RESERVED). It becomes useful to be able to search for dma
slots of a specific type or any type.
This patch introduces vfio_find_dma_from_node which starts the
search from a given node and stops on the first node that matches
the @start and @size parameters. If this node also matches the
@type parameter, the node is returned else NULL is returned.
At the moment we only have USER SLOTS so the type will always match.
In a separate patch, this function will be enhanced to pursue the
search recursively in case a node with a different type is
encountered.
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
---
v13 -> v14:
- remove top_node variable
---
drivers/vfio/vfio_iommu_type1.c | 52 +++++++++++++++++++++++++++++++++--------
1 file changed, 42 insertions(+), 10 deletions(-)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index a9f8b93..1bd16ff 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -94,25 +94,55 @@ struct vfio_group {
* into DMA'ble space using the IOMMU
*/
-static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu,
- dma_addr_t start, size_t size)
+/**
+ * vfio_find_dma_from_node: looks for a dma slot intersecting a window
+ * from a given rb tree node
+ * @top: top rb tree node where the search starts (including this node)
+ * @start: window start
+ * @size: window size
+ * @type: window type
+ */
+static struct vfio_dma *vfio_find_dma_from_node(struct rb_node *top,
+ dma_addr_t start, size_t size,
+ enum vfio_iova_type type)
{
- struct rb_node *node = iommu->dma_list.rb_node;
+ struct rb_node *node = top;
+ struct vfio_dma *dma;
while (node) {
- struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node);
-
+ dma = rb_entry(node, struct vfio_dma, node);
if (start + size <= dma->iova)
node = node->rb_left;
else if (start >= dma->iova + dma->size)
node = node->rb_right;
else
- return dma;
+ break;
}
+ if (!node)
+ return NULL;
+
+ /* a dma slot intersects our window, check the type also matches */
+ if (type == VFIO_IOVA_ANY || dma->type == type)
+ return dma;
return NULL;
}
+/**
+ * vfio_find_dma: find a dma slot intersecting a given window
+ * @iommu: vfio iommu handle
+ * @start: window base iova
+ * @size: window size
+ * @type: window type
+ */
+static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu,
+ dma_addr_t start, size_t size,
+ enum vfio_iova_type type)
+{
+ return vfio_find_dma_from_node(iommu->dma_list.rb_node,
+ start, size, type);
+}
+
static void vfio_link_dma(struct vfio_iommu *iommu, struct vfio_dma *new)
{
struct rb_node **link = &iommu->dma_list.rb_node, *parent = NULL;
@@ -484,19 +514,21 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
* mappings within the range.
*/
if (iommu->v2) {
- dma = vfio_find_dma(iommu, unmap->iova, 0);
+ dma = vfio_find_dma(iommu, unmap->iova, 0, VFIO_IOVA_USER);
if (dma && dma->iova != unmap->iova) {
ret = -EINVAL;
goto unlock;
}
- dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0);
+ dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0,
+ VFIO_IOVA_USER);
if (dma && dma->iova + dma->size != unmap->iova + unmap->size) {
ret = -EINVAL;
goto unlock;
}
}
- while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size))) {
+ while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size,
+ VFIO_IOVA_USER))) {
if (!iommu->v2 && unmap->iova > dma->iova)
break;
unmapped += dma->size;
@@ -600,7 +632,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
mutex_lock(&iommu->lock);
- if (vfio_find_dma(iommu, iova, size)) {
+ if (vfio_find_dma(iommu, iova, size, VFIO_IOVA_ANY)) {
mutex_unlock(&iommu->lock);
return -EEXIST;
}
--
1.9.1
--
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