vfio iommu type1: Fix size argument to vfio_find_dma() during DMA UNMAP.

Passing zero for the size to vfio_find_dma() isn't compatible with
matching the start address of an existing vfio_dma. Doing so triggers a
corner case. In vfio_find_dma(), when the start address is equal to
dma->iova and size is 0, check for the end of search range makes it to
take wrong side of RB-tree. That fails the search even though the address
is present in mapped dma ranges. Due to this, in vfio_dma_do_unmap(),
while checking boundary conditions, size should be set to 1 for verifying
start address of unmap range.
vfio_find_dma() is also used to verify last address in unmap range with
size = 0, but in that case address to be searched is calculated with
start + size - 1 and so it works correctly.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
[aw: changelog tweak]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Kirti Wankhede 2016-12-06 23:56:54 +05:30 committed by Alex Williamson
parent 3cedd7d75f
commit 7c03f42846

View File

@ -826,7 +826,7 @@ again:
* mappings within the range.
*/
if (iommu->v2) {
dma = vfio_find_dma(iommu, unmap->iova, 0);
dma = vfio_find_dma(iommu, unmap->iova, 1);
if (dma && dma->iova != unmap->iova) {
ret = -EINVAL;
goto unlock;