diff options
Diffstat (limited to 'drivers/infiniband/hw/mlx5/mlx5_ib.h')
| -rw-r--r-- | drivers/infiniband/hw/mlx5/mlx5_ib.h | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h index 2e2ad3918385..7e2c4a378220 100644 --- a/drivers/infiniband/hw/mlx5/mlx5_ib.h +++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h @@ -1550,4 +1550,40 @@ static inline bool rt_supported(int ts_cap) return ts_cap == MLX5_TIMESTAMP_FORMAT_CAP_REAL_TIME || ts_cap == MLX5_TIMESTAMP_FORMAT_CAP_FREE_RUNNING_AND_REAL_TIME; } + +/* + * PCI Peer to Peer is a trainwreck. If no switch is present then things + * sometimes work, depending on the pci_distance_p2p logic for excluding broken + * root complexes. However if a switch is present in the path, then things get + * really ugly depending on how the switch is setup. This table assumes that the + * root complex is strict and is validating that all req/reps are matches + * perfectly - so any scenario where it sees only half the transaction is a + * failure. + * + * CR/RR/DT ATS RO P2P + * 00X X X OK + * 010 X X fails (request is routed to root but root never sees comp) + * 011 0 X fails (request is routed to root but root never sees comp) + * 011 1 X OK + * 10X X 1 OK + * 101 X 0 fails (completion is routed to root but root didn't see req) + * 110 X 0 SLOW + * 111 0 0 SLOW + * 111 1 0 fails (completion is routed to root but root didn't see req) + * 111 1 1 OK + * + * Unfortunately we cannot reliably know if a switch is present or what the + * CR/RR/DT ACS settings are, as in a VM that is all hidden. Assume that + * CR/RR/DT is 111 if the ATS cap is enabled and follow the last three rows. + * + * For now assume if the umem is a dma_buf then it is P2P. + */ +static inline bool mlx5_umem_needs_ats(struct mlx5_ib_dev *dev, + struct ib_umem *umem, int access_flags) +{ + if (!MLX5_CAP_GEN(dev->mdev, ats) || !umem->is_dmabuf) + return false; + return access_flags & IB_ACCESS_RELAXED_ORDERING; +} + #endif /* MLX5_IB_H */ |