[PATCH v7 2/7] vfio/type1: vfio_find_dma accepting a type argument

Eric Auger
2016-04-19T17:26:54Z

In our RB-tree we now have 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 proposes an implementation for that modality and also
changes the existing callers using the USER type.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
---
drivers/vfio/vfio_iommu_type1.c | 63 ++++++++++++++++++++++++++++++++++-------
1 file changed, 53 insertions(+), 10 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index aaf5a6c..2d769d4 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -98,23 +98,64 @@ 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
+ 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;
+
+ /* restart 2 searches skipping the current node */
+ if (start < dma->iova) {
+ dma = vfio_find_dma_from_node(node->rb_left, start,
+ size, type);
+ if (dma)
return dma;
}
+ if (start + size > dma->iova + dma->size)
+ dma = vfio_find_dma_from_node(node->rb_right, start,
+ size, type);
+ return dma;
+}
+
+/**
+ * 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)
+{
+ struct rb_node *top_node = iommu->dma_list.rb_node;

- return NULL;
+ return vfio_find_dma_from_node(top_node, start, size, type);
}

static void vfio_link_dma(struct vfio_iommu *iommu, struct vfio_dma *new)
@@ -488,19 +529,21 @@ 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;
@@ -604,7 +647,7 @@ 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