[PATCH v1 10/10] vfio/pci: Add dma-buf export support for MMIO regions

[Leon Romanovsky]

On Mon, Aug 04, 2025 at 04:00:45PM +0300, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro at nvidia.com>
> 
> Add support for exporting PCI device MMIO regions through dma-buf,
> enabling safe sharing of non-struct page memory with controlled
> lifetime management. This allows RDMA and other subsystems to import
> dma-buf FDs and build them into memory regions for PCI P2P operations.
> 
> The implementation provides a revocable attachment mechanism using
> dma-buf move operations. MMIO regions are normally pinned as BARs
> don't change physical addresses, but access is revoked when the VFIO
> device is closed or a PCI reset is issued. This ensures kernel
> self-defense against potentially hostile userspace.
> 
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
> Signed-off-by: Vivek Kasireddy <vivek.kasireddy at intel.com>
> Signed-off-by: Leon Romanovsky <leonro at nvidia.com>
> ---
>  drivers/vfio/pci/Kconfig           |  20 ++
>  drivers/vfio/pci/Makefile          |   2 +
>  drivers/vfio/pci/vfio_pci_config.c |  22 +-
>  drivers/vfio/pci/vfio_pci_core.c   |  25 +-
>  drivers/vfio/pci/vfio_pci_dmabuf.c | 390 +++++++++++++++++++++++++++++
>  drivers/vfio/pci/vfio_pci_priv.h   |  23 ++
>  include/linux/dma-buf.h            |   1 +
>  include/linux/vfio_pci_core.h      |   3 +
>  include/uapi/linux/vfio.h          |  25 ++
>  9 files changed, 506 insertions(+), 5 deletions(-)
>  create mode 100644 drivers/vfio/pci/vfio_pci_dmabuf.c

<...>

> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> index d58e329ac0e71..f14b413aae48d 100644
> --- a/include/linux/dma-buf.h
> +++ b/include/linux/dma-buf.h
> @@ -483,6 +483,7 @@ struct dma_buf_attach_ops {
>   * @dev: device attached to the buffer.
>   * @node: list of dma_buf_attachment, protected by dma_resv lock of the dmabuf.
>   * @peer2peer: true if the importer can handle peer resources without pages.
> + * #state: DMA structure to provide support for physical addresses DMA interface

This is rebase error, there is no need in this hunk.

Thanks