From: Leon Romanovsky <[email protected]> Till now VFIO has rejected pinned importers, largely to avoid being used with the RDMA pinned importer that cannot handle a move_notify() to revoke access.
Using dma_buf_attach_revocable() it can tell the difference between pinned importers that support the flow described in dma_buf_invalidate_mappings() and those that don't. Thus permit compatible pinned importers. This is one of two items IOMMUFD requires to remove its private interface to VFIO's dma-buf. Reviewed-by: Kevin Tian <[email protected]> Reviewed-by: Alex Williamson <[email protected]> Reviewed-by: Christian König <[email protected]> Signed-off-by: Leon Romanovsky <[email protected]> --- drivers/vfio/pci/vfio_pci_dmabuf.c | 37 ++++++++++--------------------------- 1 file changed, 10 insertions(+), 27 deletions(-) diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c index 485515629fe4..20d8a452471d 100644 --- a/drivers/vfio/pci/vfio_pci_dmabuf.c +++ b/drivers/vfio/pci/vfio_pci_dmabuf.c @@ -22,16 +22,6 @@ struct vfio_pci_dma_buf { u8 revoked : 1; }; -static int vfio_pci_dma_buf_pin(struct dma_buf_attachment *attachment) -{ - return -EOPNOTSUPP; -} - -static void vfio_pci_dma_buf_unpin(struct dma_buf_attachment *attachment) -{ - /* Do nothing */ -} - static int vfio_pci_dma_buf_attach(struct dma_buf *dmabuf, struct dma_buf_attachment *attachment) { @@ -43,6 +33,9 @@ static int vfio_pci_dma_buf_attach(struct dma_buf *dmabuf, if (priv->revoked) return -ENODEV; + if (!dma_buf_attach_revocable(attachment)) + return -EOPNOTSUPP; + return 0; } @@ -107,8 +100,6 @@ static void vfio_pci_dma_buf_release(struct dma_buf *dmabuf) } static const struct dma_buf_ops vfio_pci_dmabuf_ops = { - .pin = vfio_pci_dma_buf_pin, - .unpin = vfio_pci_dma_buf_unpin, .attach = vfio_pci_dma_buf_attach, .map_dma_buf = vfio_pci_dma_buf_map, .unmap_dma_buf = vfio_pci_dma_buf_unmap, @@ -357,7 +348,8 @@ void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, bool revoked) if (priv->revoked != revoked) { dma_resv_lock(priv->dmabuf->resv, NULL); - priv->revoked = revoked; + if (revoked) + priv->revoked = true; dma_buf_invalidate_mappings(priv->dmabuf); dma_resv_wait_timeout(priv->dmabuf->resv, DMA_RESV_USAGE_BOOKKEEP, false, @@ -365,17 +357,7 @@ void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, bool revoked) dma_resv_unlock(priv->dmabuf->resv); if (revoked) { kref_put(&priv->kref, vfio_pci_dma_buf_done); - /* Let's wait till all DMA unmap are completed. */ - wait = wait_for_completion_timeout( - &priv->comp, secs_to_jiffies(1)); - /* - * If you see this WARN_ON, it means that - * importer didn't call unmap in response to - * dma_buf_invalidate_mappings() which is not - * allowed. - */ - WARN(!wait, - "Timed out waiting for DMABUF unmap, importer has a broken invalidate_mapping()"); + wait_for_completion(&priv->comp); } else { /* * Kref is initialize again, because when revoke @@ -389,6 +371,9 @@ void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, bool revoked) * priv->revoked == true. */ reinit_completion(&priv->comp); + dma_resv_lock(priv->dmabuf->resv, NULL); + priv->revoked = false; + dma_resv_unlock(priv->dmabuf->resv); } } fput(priv->dmabuf->file); @@ -417,9 +402,7 @@ void vfio_pci_dma_buf_cleanup(struct vfio_pci_core_device *vdev) MAX_SCHEDULE_TIMEOUT); dma_resv_unlock(priv->dmabuf->resv); kref_put(&priv->kref, vfio_pci_dma_buf_done); - wait = wait_for_completion_timeout(&priv->comp, - secs_to_jiffies(1)); - WARN_ON(!wait); + wait_for_completion(&priv->comp); vfio_device_put_registration(&vdev->vdev); fput(priv->dmabuf->file); } -- 2.52.0
