[PATCH v4 7/8] vfio: Wait for dma-buf invalidation to complete

Leon Romanovsky
2026-01-21T13:00:05Z

From: Leon Romanovsky <leonro@nvidia.com>

dma-buf invalidation is performed asynchronously by hardware, so VFIO must
wait until all affected objects have been fully invalidated.

Fixes: 5d74781ebc86 ("vfio/pci: Add dma-buf export support for MMIO regions")
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
drivers/vfio/pci/vfio_pci_dmabuf.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c
index 362e3d149817..5fceefc40e27 100644
--- a/drivers/vfio/pci/vfio_pci_dmabuf.c
+++ b/drivers/vfio/pci/vfio_pci_dmabuf.c
@@ -321,6 +321,9 @@ void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, bool revoked)
dma_resv_lock(priv->dmabuf->resv, NULL);
priv->revoked = revoked;
dma_buf_invalidate_mappings(priv->dmabuf);
+ dma_resv_wait_timeout(priv->dmabuf->resv,
+ DMA_RESV_USAGE_BOOKKEEP, false,
+ MAX_SCHEDULE_TIMEOUT);
dma_resv_unlock(priv->dmabuf->resv);
}
fput(priv->dmabuf->file);
@@ -342,6 +345,9 @@ void vfio_pci_dma_buf_cleanup(struct vfio_pci_core_device *vdev)
priv->vdev = NULL;
priv->revoked = true;
dma_buf_invalidate_mappings(priv->dmabuf);
+ dma_resv_wait_timeout(priv->dmabuf->resv,
+ DMA_RESV_USAGE_BOOKKEEP, false,
+ MAX_SCHEDULE_TIMEOUT);
dma_resv_unlock(priv->dmabuf->resv);
vfio_device_put_registration(&vdev->vdev);
fput(priv->dmabuf->file);

--
2.52.0