[PATCH v4 6/8] iommufd: Pin dma-buf importer for revoke semantics

Leon Romanovsky posted 8 patches 2 weeks, 5 days ago
There is a newer version of this series
[PATCH v4 6/8] iommufd: Pin dma-buf importer for revoke semantics
Posted by Leon Romanovsky 2 weeks, 5 days ago
From: Leon Romanovsky <leonro@nvidia.com>

IOMMUFD does not support page fault handling, and after a call to
.invalidate_mappings() all mappings become invalid. Ensure that
the IOMMUFD dma-buf importer is bound to a revoke‑aware dma-buf
exporter (for example, VFIO).

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/iommu/iommufd/pages.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c
index 76f900fa1687..a5eb2bc4ef48 100644
--- a/drivers/iommu/iommufd/pages.c
+++ b/drivers/iommu/iommufd/pages.c
@@ -1501,16 +1501,22 @@ static int iopt_map_dmabuf(struct iommufd_ctx *ictx, struct iopt_pages *pages,
 		mutex_unlock(&pages->mutex);
 	}
 
-	rc = sym_vfio_pci_dma_buf_iommufd_map(attach, &pages->dmabuf.phys);
+	rc = dma_buf_pin(attach);
 	if (rc)
 		goto err_detach;
 
+	rc = sym_vfio_pci_dma_buf_iommufd_map(attach, &pages->dmabuf.phys);
+	if (rc)
+		goto err_unpin;
+
 	dma_resv_unlock(dmabuf->resv);
 
 	/* On success iopt_release_pages() will detach and put the dmabuf. */
 	pages->dmabuf.attach = attach;
 	return 0;
 
+err_unpin:
+	dma_buf_unpin(attach);
 err_detach:
 	dma_resv_unlock(dmabuf->resv);
 	dma_buf_detach(dmabuf, attach);
@@ -1656,6 +1662,7 @@ void iopt_release_pages(struct kref *kref)
 	if (iopt_is_dmabuf(pages) && pages->dmabuf.attach) {
 		struct dma_buf *dmabuf = pages->dmabuf.attach->dmabuf;
 
+		dma_buf_unpin(pages->dmabuf.attach);
 		dma_buf_detach(dmabuf, pages->dmabuf.attach);
 		dma_buf_put(dmabuf);
 		WARN_ON(!list_empty(&pages->dmabuf.tracker));

-- 
2.52.0