From: Yishai Hadas yishaih@nvidia.com
Enable p2pdma on the mlx5 PCI device to allow DMABUF-based peer-to-peer DMA mappings.
Add implementation of the mmap_get_pfns and pgoff_to_mmap_entry device operations required for DMABUF support in the mlx5 RDMA driver.
The pgoff_to_mmap_entry operation converts a page offset to the corresponding rdma_user_mmap_entry by extracting the command and index from the offset and looking it up in the ucontext's mmap_xa.
The mmap_get_pfns operation retrieves the physical address and length from the mmap entry and obtains the p2pdma provider for the underlying PCI device, which is needed for peer-to-peer DMA operations with DMABUFs.
Signed-off-by: Yishai Hadas yishaih@nvidia.com Signed-off-by: Edward Srouji edwards@nvidia.com --- drivers/infiniband/hw/mlx5/main.c | 72 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 72 insertions(+)
diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c index e81080622283..f97c86c96d83 100644 --- a/drivers/infiniband/hw/mlx5/main.c +++ b/drivers/infiniband/hw/mlx5/main.c @@ -2446,6 +2446,70 @@ static int mlx5_ib_mmap_clock_info_page(struct mlx5_ib_dev *dev, virt_to_page(dev->mdev->clock_info)); }
+static int phys_addr_to_bar(struct pci_dev *pdev, phys_addr_t pa) +{ + resource_size_t start, end; + int bar; + + for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) { + /* Skip BARs not present or not memory-mapped */ + if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) + continue; + + start = pci_resource_start(pdev, bar); + end = pci_resource_end(pdev, bar); + + if (!start || !end) + continue; + + if (pa >= start && pa <= end) + return bar; + } + + return -1; +} + +static int mlx5_ib_mmap_get_pfns(struct rdma_user_mmap_entry *entry, + struct dma_buf_phys_vec *phys_vec, + struct p2pdma_provider **provider) +{ + struct mlx5_user_mmap_entry *mentry = to_mmmap(entry); + struct pci_dev *pdev = to_mdev(entry->ucontext->device)->mdev->pdev; + int bar; + + phys_vec->paddr = mentry->address; + phys_vec->len = entry->npages * PAGE_SIZE; + + bar = phys_addr_to_bar(pdev, phys_vec->paddr); + if (bar < 0) + return -EINVAL; + + *provider = pcim_p2pdma_provider(pdev, bar); + /* If the kernel was not compiled with CONFIG_PCI_P2PDMA the + * functionality is not supported. + */ + if (!*provider) + return -EOPNOTSUPP; + + return 0; +} + +static struct rdma_user_mmap_entry * +mlx5_ib_pgoff_to_mmap_entry(struct ib_ucontext *ucontext, off_t pg_off) +{ + unsigned long entry_pgoff; + unsigned long idx; + u8 command; + + pg_off = pg_off >> PAGE_SHIFT; + command = get_command(pg_off); + idx = get_extended_index(pg_off); + + entry_pgoff = command << 16 | idx; + + return rdma_user_mmap_entry_get_pgoff(ucontext, entry_pgoff); +} + static void mlx5_ib_mmap_free(struct rdma_user_mmap_entry *entry) { struct mlx5_user_mmap_entry *mentry = to_mmmap(entry); @@ -4360,7 +4424,13 @@ static int mlx5_ib_stage_init_init(struct mlx5_ib_dev *dev) if (err) goto err_mp;
+ err = pcim_p2pdma_init(mdev->pdev); + if (err && err != -EOPNOTSUPP) + goto err_dd; + return 0; +err_dd: + mlx5_ib_data_direct_cleanup(dev); err_mp: mlx5_ib_cleanup_multiport_master(dev); err: @@ -4412,11 +4482,13 @@ static const struct ib_device_ops mlx5_ib_dev_ops = { .map_mr_sg_pi = mlx5_ib_map_mr_sg_pi, .mmap = mlx5_ib_mmap, .mmap_free = mlx5_ib_mmap_free, + .mmap_get_pfns = mlx5_ib_mmap_get_pfns, .modify_cq = mlx5_ib_modify_cq, .modify_device = mlx5_ib_modify_device, .modify_port = mlx5_ib_modify_port, .modify_qp = mlx5_ib_modify_qp, .modify_srq = mlx5_ib_modify_srq, + .pgoff_to_mmap_entry = mlx5_ib_pgoff_to_mmap_entry, .pre_destroy_cq = mlx5_ib_pre_destroy_cq, .poll_cq = mlx5_ib_poll_cq, .post_destroy_cq = mlx5_ib_post_destroy_cq,