This series adds TLP Processing Hints (TPH) support to the VFIO dma-buf
export path, allowing importing drivers (e.g. mlx5) to use the
exporter's steering tag when performing peer-to-peer DMA into a
VFIO-owned device.
Patch 1 adds the dma-buf get_tph callback and the new vfio uAPI.
Patch 2 exposes the enabled TPH requester type through a small PCI/TPH
helper so callers don't reach into pci_dev internals.
Patch 3 wires up the mlx5 RDMA driver as a consumer.
Changes since v3:
- vfio: TPH SET is now write-once per dma-buf; a second
VFIO_DEVICE_FEATURE_DMA_BUF_TPH on the same dma-buf returns -EBUSY.
- vfio: annotate priv->vdev with READ_ONCE/WRITE_ONCE across the
cleanup, release, and feature-set paths to make the existing
cleanup/release coordination explicit.
- vfio uAPI: shrink steering_tag from __u16 to __u8 to match the
8-bit ST width, and drop the trailing reserved[3] in
struct vfio_device_feature_dma_buf_tph (struct is now 12 bytes).
- Split the new PCI/TPH helper into its own patch (now patch 2) and
rename it from pcie_tph_get_st_width() to
pcie_tph_enabled_req_type(), exposing the enabled requester mode
rather than just the ST width.
- mlx5: release the allocated ST index before the MR is pushed back
to the FRMR pool, so a reused MR cannot reference a freed firmware
ST entry.
- mlx5: free mlx5_st_idx_data when its refcount reaches zero, fixing
a leak that accumulated across repeated alloc/dealloc cycles.
- Initialize ret in mlx5_st_create() and mlx5_st_alloc_index_by_tag()
to silence -Wsometimes-uninitialized warnings reported by the
kernel test robot under clang.
Previous link:
v3:
https://lore.kernel.org/linux-pci/[email protected]/
v2: https://lore.kernel.org/linux-pci/[email protected]/
Zhiping Zhang (3):
vfio: add dma-buf get_tph callback and DMA_BUF_TPH feature
PCI/TPH: expose the enabled TPH requester type
RDMA/mlx5: get tph for p2p access when registering dma-buf mr
drivers/infiniband/hw/mlx5/mlx5_ib.h | 6 +
drivers/infiniband/hw/mlx5/mr.c | 86 ++++++++++-
.../net/ethernet/mellanox/mlx5/core/lib/st.c | 28 ++--
drivers/pci/tph.c | 12 ++
drivers/vfio/pci/vfio_pci_core.c | 3 +
drivers/vfio/pci/vfio_pci_dmabuf.c | 134 +++++++++++++++++-
drivers/vfio/pci/vfio_pci_priv.h | 12 ++
include/linux/dma-buf.h | 21 +++
include/linux/mlx5/driver.h | 7 +
include/linux/pci-tph.h | 2 +
include/uapi/linux/vfio.h | 35 +++++
11 files changed, 327 insertions(+), 19 deletions(-)
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2.53.0-Meta
