linux-kernel - [PATCH v5 7/8] vfio: Permit VFIO to work with pinned importers

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Message-ID: <20260124-dmabuf-revoke-v5-7-f98fca917e96@nvidia.com>
Date: Sat, 24 Jan 2026 21:14:19 +0200
From: Leon Romanovsky <leon@...nel.org>
To: Sumit Semwal <sumit.semwal@...aro.org>,
	Christian König <christian.koenig@....com>,
	Alex Deucher <alexander.deucher@....com>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Gerd Hoffmann <kraxel@...hat.com>,
	Dmitry Osipenko <dmitry.osipenko@...labora.com>,
	Gurchetan Singh <gurchetansingh@...omium.org>,
	Chia-I Wu <olvaffe@...il.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	Lucas De Marchi <lucas.demarchi@...el.com>,
	Thomas Hellström <thomas.hellstrom@...ux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@...el.com>,
	Jason Gunthorpe <jgg@...pe.ca>,
	Leon Romanovsky <leon@...nel.org>,
	Kevin Tian <kevin.tian@...el.com>,
	Joerg Roedel <joro@...tes.org>,
	Will Deacon <will@...nel.org>,
	Robin Murphy <robin.murphy@....com>,
	Felix Kuehling <Felix.Kuehling@....com>,
	Alex Williamson <alex@...zbot.org>,
	Ankit Agrawal <ankita@...dia.com>,
	Vivek Kasireddy <vivek.kasireddy@...el.com>
Cc: linux-media@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	linaro-mm-sig@...ts.linaro.org,
	linux-kernel@...r.kernel.org,
	amd-gfx@...ts.freedesktop.org,
	virtualization@...ts.linux.dev,
	intel-xe@...ts.freedesktop.org,
	linux-rdma@...r.kernel.org,
	iommu@...ts.linux.dev,
	kvm@...r.kernel.org
Subject: [PATCH v5 7/8] vfio: Permit VFIO to work with pinned importers

From: Leon Romanovsky <leonro@...dia.com>

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.

Signed-off-by: Leon Romanovsky <leonro@...dia.com>
---
 drivers/vfio/pci/vfio_pci_dmabuf.c | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c
index 485515629fe4..3c8dc56e2238 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,

-- 
2.52.0