On Mon, Aug 04, 2025 at 04:00:45PM +0300, Leon Romanovsky wrote:
From: Leon Romanovsky leonro@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@nvidia.com Signed-off-by: Vivek Kasireddy vivek.kasireddy@intel.com Signed-off-by: Leon Romanovsky leonro@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
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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