This patch add HMM specific support for hardware page faulting of user memory region.
Changed since v1: - Adapt to HMM page table changes. - Turn some sanity test to BUG_ON(). Signed-off-by: Jérôme Glisse <[email protected]> --- drivers/infiniband/hw/mlx5/odp.c | 144 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 143 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c index d8156ec..5b84b10 100644 --- a/drivers/infiniband/hw/mlx5/odp.c +++ b/drivers/infiniband/hw/mlx5/odp.c @@ -56,6 +56,52 @@ static struct mlx5_ib_mr *mlx5_ib_odp_find_mr_lkey(struct mlx5_ib_dev *dev, #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM +struct mlx5_hmm_pfault { + struct mlx5_ib_mr *mlx5_ib_mr; + u64 start_idx; + dma_addr_t access_mask; + unsigned npages; + struct hmm_event event; +}; + +static int mlx5_hmm_pfault(struct mlx5_ib_dev *mlx5_ib_dev, + struct hmm_mirror *mirror, + const struct hmm_event *event) +{ + struct mlx5_hmm_pfault *pfault; + struct hmm_pt_iter iter; + unsigned long addr, cnt; + int ret; + + pfault = container_of(event, struct mlx5_hmm_pfault, event); + hmm_pt_iter_init(&iter, &mirror->pt); + + for (addr = event->start, cnt = 0; addr < event->end; + addr += PAGE_SIZE, ++cnt) { + unsigned long next = event->end; + dma_addr_t *ptep; + + /* Get and lock pointer to mirror page table. */ + ptep = hmm_pt_iter_lookup(&iter, addr, &next); + BUG_ON(!ptep); + for (; ptep && addr < next; addr += PAGE_SIZE, ptep++) { + /* This could be BUG_ON() as it can not happen. */ + BUG_ON(!hmm_pte_test_valid_dma(ptep)); + BUG_ON((pfault->access_mask & ODP_WRITE_ALLOWED_BIT) && + !hmm_pte_test_write(ptep)); + if (hmm_pte_test_write(ptep)) + hmm_pte_set_bit(ptep, ODP_WRITE_ALLOWED_SHIFT); + hmm_pte_set_bit(ptep, ODP_READ_ALLOWED_SHIFT); + pfault->npages++; + } + } + ret = mlx5_ib_update_mtt(pfault->mlx5_ib_mr, + pfault->start_idx, + cnt, 0, &iter); + hmm_pt_iter_fini(&iter); + return ret; +} + int mlx5_ib_umem_invalidate(struct ib_umem *umem, u64 start, u64 end, void *cookie) { @@ -181,12 +227,19 @@ static int mlx5_hmm_update(struct hmm_mirror *mirror, struct hmm_event *event) { struct device *device = mirror->device->dev; + struct mlx5_ib_dev *mlx5_ib_dev; + struct ib_device *ib_device; int ret = 0; + ib_device = container_of(mirror->device, struct ib_device, hmm_dev); + mlx5_ib_dev = to_mdev(ib_device); + switch (event->etype) { case HMM_DEVICE_RFAULT: case HMM_DEVICE_WFAULT: - /* FIXME implement. */ + ret = mlx5_hmm_pfault(mlx5_ib_dev, mirror, event); + if (ret) + return ret; break; case HMM_NONE: default: @@ -229,6 +282,95 @@ void mlx5_dev_fini_odp_hmm(struct ib_device *ib_device) hmm_device_unregister(&ib_device->hmm_dev); } +/* + * Handle a single data segment in a page-fault WQE. + * + * Returns number of pages retrieved on success. The caller will continue to + * the next data segment. + * Can return the following error codes: + * -EAGAIN to designate a temporary error. The caller will abort handling the + * page fault and resolve it. + * -EFAULT when there's an error mapping the requested pages. The caller will + * abort the page fault handling and possibly move the QP to an error state. + * On other errors the QP should also be closed with an error. + */ +static int pagefault_single_data_segment(struct mlx5_ib_qp *qp, + struct mlx5_ib_pfault *pfault, + u32 key, u64 io_virt, size_t bcnt, + u32 *bytes_mapped) +{ + struct mlx5_ib_dev *mlx5_ib_dev = to_mdev(qp->ibqp.pd->device); + struct ib_mirror *ib_mirror; + struct mlx5_hmm_pfault hmm_pfault; + int srcu_key; + int ret = 0; + + srcu_key = srcu_read_lock(&mlx5_ib_dev->mr_srcu); + hmm_pfault.mlx5_ib_mr = mlx5_ib_odp_find_mr_lkey(mlx5_ib_dev, key); + /* + * If we didn't find the MR, it means the MR was closed while we were + * handling the ODP event. In this case we return -EFAULT so that the + * QP will be closed. + */ + if (!hmm_pfault.mlx5_ib_mr || !hmm_pfault.mlx5_ib_mr->ibmr.pd) { + pr_err("Failed to find relevant mr for lkey=0x%06x, probably the MR was destroyed\n", + key); + ret = -EFAULT; + goto srcu_unlock; + } + if (!hmm_pfault.mlx5_ib_mr->umem->odp_data) { + pr_debug("skipping non ODP MR (lkey=0x%06x) in page fault handler.\n", + key); + if (bytes_mapped) + *bytes_mapped += + (bcnt - pfault->mpfault.bytes_committed); + goto srcu_unlock; + } + if (hmm_pfault.mlx5_ib_mr->ibmr.pd != qp->ibqp.pd) { + pr_err("Page-fault with different PDs for QP and MR.\n"); + ret = -EFAULT; + goto srcu_unlock; + } + + ib_mirror = hmm_pfault.mlx5_ib_mr->umem->odp_data->ib_mirror; + if (ib_mirror->base.hmm == NULL) { + /* Somehow the mirror was kill from under us. */ + ret = -EFAULT; + goto srcu_unlock; + } + + /* + * Avoid branches - this code will perform correctly + * in all iterations (in iteration 2 and above, + * bytes_committed == 0). + */ + io_virt += pfault->mpfault.bytes_committed; + bcnt -= pfault->mpfault.bytes_committed; + + hmm_pfault.npages = 0; + hmm_pfault.start_idx = (io_virt - (hmm_pfault.mlx5_ib_mr->mmr.iova & + PAGE_MASK)) >> PAGE_SHIFT; + hmm_pfault.access_mask = ODP_READ_ALLOWED_BIT; + hmm_pfault.access_mask |= hmm_pfault.mlx5_ib_mr->umem->writable ? + ODP_WRITE_ALLOWED_BIT : 0; + hmm_pfault.event.start = io_virt & PAGE_MASK; + hmm_pfault.event.end = PAGE_ALIGN(io_virt + bcnt); + hmm_pfault.event.etype = hmm_pfault.mlx5_ib_mr->umem->writable ? + HMM_DEVICE_WFAULT : HMM_DEVICE_RFAULT; + ret = hmm_mirror_fault(&ib_mirror->base, &hmm_pfault.event); + + if (!ret && hmm_pfault.npages && bytes_mapped) { + u32 new_mappings = hmm_pfault.npages * PAGE_SIZE - + (io_virt - round_down(io_virt, PAGE_SIZE)); + *bytes_mapped += min_t(u32, new_mappings, bcnt); + } + +srcu_unlock: + srcu_read_unlock(&mlx5_ib_dev->mr_srcu, srcu_key); + pfault->mpfault.bytes_committed = 0; + return ret ? ret : hmm_pfault.npages; +} + #else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */ -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
