To support driver-allocated vIOMMU objects, it's required for IOMMU driver to call the provided iommufd_viommu_alloc helper to embed the core struct. However, there is no guarantee that every driver will call it and allocate objects properly.
Make the iommufd_object_finalize/abort functions more robust to verify if the xarray slot indexed by the input obj->id is having an XA_ZERO_ENTRY, which is the reserved value stored by xa_alloc via iommufd_object_alloc.
Suggested-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Nicolin Chen nicolinc@nvidia.com --- drivers/iommu/iommufd/main.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c index 3c32b440471b..30e6c2af3b45 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -41,20 +41,26 @@ static struct miscdevice vfio_misc_dev; void iommufd_object_finalize(struct iommufd_ctx *ictx, struct iommufd_object *obj) { + XA_STATE(xas, &ictx->objects, obj->id); void *old;
- old = xa_store(&ictx->objects, obj->id, obj, GFP_KERNEL); - /* obj->id was returned from xa_alloc() so the xa_store() cannot fail */ - WARN_ON(old); + xa_lock(&ictx->objects); + old = xas_store(&xas, obj); + xa_unlock(&ictx->objects); + /* obj->id was returned from xa_alloc() so the xas_store() cannot fail */ + WARN_ON(old != XA_ZERO_ENTRY); }
/* Undo _iommufd_object_alloc() if iommufd_object_finalize() was not called */ void iommufd_object_abort(struct iommufd_ctx *ictx, struct iommufd_object *obj) { + XA_STATE(xas, &ictx->objects, obj->id); void *old;
- old = xa_erase(&ictx->objects, obj->id); - WARN_ON(old); + xa_lock(&ictx->objects); + old = xas_store(&xas, NULL); + xa_unlock(&ictx->objects); + WARN_ON(old != XA_ZERO_ENTRY); kfree(obj); }