On Wed, Feb 04, 2026 at 05:21:45PM +0100, Christian König wrote:
> On 1/31/26 06:34, Leon Romanovsky wrote:
> > 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 | 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 78d47e260f34..a5fb80e068ee 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 */
> > -}
> > -
>
> This chunk here doesn't want to apply to drm-misc-next, my educated guess is
> that the patch adding those lines is missing in that tree.
>
> How should we handle that? Patches 1-3 have already been pushed to
> drm-misc-next and I would rather like to push patches 4-6 through that branch
> as well.
There is no need for a backmerge; it should go in through the shared
branch. Alex has created the tag vfio-v6.19-rc8, which is v6.19-rc6 plus
the VFIO pin patch.
You need to merge this tag into drm-misc-next. That will ensure that
Linus, DRM, and VFIO all see the same SHA-1, and that patches 5–6 can be
applied afterward.
Thanks
>
> I can request a backmerge from the drm-misc-next maintainers, but then we
> clearly don't get that upstream this week.
>
> Regards,
> Christian.
>
> > 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,
> >
>
>
