IB/mlx5: Handle page faults
This patch implement a page fault handler (leaving the pages pinned as of time being). The page fault handler handles initiator and responder page faults for UD/RC transports, for send/receive operations, as well as RDMA read/write initiator support. Signed-off-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Shachar Raindel <raindel@mellanox.com> Signed-off-by: Haggai Eran <haggaie@mellanox.com> Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Haggai Eran
Roland Dreier
parent
6aec21f6a8
commit
7bdf65d411
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@ -30,6 +30,9 @@
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* SOFTWARE.
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*/
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#include <rdma/ib_umem.h>
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#include <rdma/ib_umem_odp.h>
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#include "mlx5_ib.h"
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struct workqueue_struct *mlx5_ib_page_fault_wq;
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@ -85,12 +88,417 @@ static void mlx5_ib_page_fault_resume(struct mlx5_ib_qp *qp,
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qp->mqp.qpn);
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}
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/*
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* Handle a single data segment in a page-fault WQE.
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*
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* Returns number of pages retrieved on success. The caller will continue to
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* the next data segment.
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* Can return the following error codes:
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* -EAGAIN to designate a temporary error. The caller will abort handling the
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* page fault and resolve it.
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* -EFAULT when there's an error mapping the requested pages. The caller will
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* abort the page fault handling and possibly move the QP to an error state.
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* On other errors the QP should also be closed with an error.
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*/
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static int pagefault_single_data_segment(struct mlx5_ib_qp *qp,
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struct mlx5_ib_pfault *pfault,
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u32 key, u64 io_virt, size_t bcnt,
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u32 *bytes_mapped)
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{
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struct mlx5_ib_dev *mib_dev = to_mdev(qp->ibqp.pd->device);
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int srcu_key;
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unsigned int current_seq;
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u64 start_idx;
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int npages = 0, ret = 0;
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struct mlx5_ib_mr *mr;
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u64 access_mask = ODP_READ_ALLOWED_BIT;
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srcu_key = srcu_read_lock(&mib_dev->mr_srcu);
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mr = mlx5_ib_odp_find_mr_lkey(mib_dev, key);
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/*
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* If we didn't find the MR, it means the MR was closed while we were
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* handling the ODP event. In this case we return -EFAULT so that the
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* QP will be closed.
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*/
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if (!mr || !mr->ibmr.pd) {
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pr_err("Failed to find relevant mr for lkey=0x%06x, probably the MR was destroyed\n",
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key);
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ret = -EFAULT;
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goto srcu_unlock;
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}
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if (!mr->umem->odp_data) {
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pr_debug("skipping non ODP MR (lkey=0x%06x) in page fault handler.\n",
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key);
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if (bytes_mapped)
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*bytes_mapped +=
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(bcnt - pfault->mpfault.bytes_committed);
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goto srcu_unlock;
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}
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if (mr->ibmr.pd != qp->ibqp.pd) {
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pr_err("Page-fault with different PDs for QP and MR.\n");
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ret = -EFAULT;
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goto srcu_unlock;
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}
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current_seq = ACCESS_ONCE(mr->umem->odp_data->notifiers_seq);
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/*
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* Avoid branches - this code will perform correctly
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* in all iterations (in iteration 2 and above,
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* bytes_committed == 0).
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*/
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io_virt += pfault->mpfault.bytes_committed;
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bcnt -= pfault->mpfault.bytes_committed;
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start_idx = (io_virt - (mr->mmr.iova & PAGE_MASK)) >> PAGE_SHIFT;
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if (mr->umem->writable)
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access_mask |= ODP_WRITE_ALLOWED_BIT;
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npages = ib_umem_odp_map_dma_pages(mr->umem, io_virt, bcnt,
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access_mask, current_seq);
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if (npages < 0) {
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ret = npages;
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goto srcu_unlock;
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}
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if (npages > 0) {
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mutex_lock(&mr->umem->odp_data->umem_mutex);
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/*
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* No need to check whether the MTTs really belong to
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* this MR, since ib_umem_odp_map_dma_pages already
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* checks this.
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*/
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ret = mlx5_ib_update_mtt(mr, start_idx, npages, 0);
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mutex_unlock(&mr->umem->odp_data->umem_mutex);
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if (ret < 0) {
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pr_err("Failed to update mkey page tables\n");
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goto srcu_unlock;
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}
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if (bytes_mapped) {
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u32 new_mappings = npages * PAGE_SIZE -
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(io_virt - round_down(io_virt, PAGE_SIZE));
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*bytes_mapped += min_t(u32, new_mappings, bcnt);
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}
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}
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srcu_unlock:
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srcu_read_unlock(&mib_dev->mr_srcu, srcu_key);
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pfault->mpfault.bytes_committed = 0;
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return ret ? ret : npages;
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}
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/**
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* Parse a series of data segments for page fault handling.
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*
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* @qp the QP on which the fault occurred.
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* @pfault contains page fault information.
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* @wqe points at the first data segment in the WQE.
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* @wqe_end points after the end of the WQE.
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* @bytes_mapped receives the number of bytes that the function was able to
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* map. This allows the caller to decide intelligently whether
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* enough memory was mapped to resolve the page fault
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* successfully (e.g. enough for the next MTU, or the entire
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* WQE).
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* @total_wqe_bytes receives the total data size of this WQE in bytes (minus
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* the committed bytes).
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*
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* Returns the number of pages loaded if positive, zero for an empty WQE, or a
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* negative error code.
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*/
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static int pagefault_data_segments(struct mlx5_ib_qp *qp,
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struct mlx5_ib_pfault *pfault, void *wqe,
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void *wqe_end, u32 *bytes_mapped,
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u32 *total_wqe_bytes, int receive_queue)
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{
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int ret = 0, npages = 0;
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u64 io_virt;
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u32 key;
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u32 byte_count;
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size_t bcnt;
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int inline_segment;
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/* Skip SRQ next-WQE segment. */
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if (receive_queue && qp->ibqp.srq)
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wqe += sizeof(struct mlx5_wqe_srq_next_seg);
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if (bytes_mapped)
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*bytes_mapped = 0;
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if (total_wqe_bytes)
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*total_wqe_bytes = 0;
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while (wqe < wqe_end) {
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struct mlx5_wqe_data_seg *dseg = wqe;
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io_virt = be64_to_cpu(dseg->addr);
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key = be32_to_cpu(dseg->lkey);
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byte_count = be32_to_cpu(dseg->byte_count);
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inline_segment = !!(byte_count & MLX5_INLINE_SEG);
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bcnt = byte_count & ~MLX5_INLINE_SEG;
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if (inline_segment) {
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bcnt = bcnt & MLX5_WQE_INLINE_SEG_BYTE_COUNT_MASK;
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wqe += ALIGN(sizeof(struct mlx5_wqe_inline_seg) + bcnt,
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16);
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} else {
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wqe += sizeof(*dseg);
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}
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/* receive WQE end of sg list. */
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if (receive_queue && bcnt == 0 && key == MLX5_INVALID_LKEY &&
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io_virt == 0)
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break;
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if (!inline_segment && total_wqe_bytes) {
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*total_wqe_bytes += bcnt - min_t(size_t, bcnt,
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pfault->mpfault.bytes_committed);
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}
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/* A zero length data segment designates a length of 2GB. */
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if (bcnt == 0)
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bcnt = 1U << 31;
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if (inline_segment || bcnt <= pfault->mpfault.bytes_committed) {
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pfault->mpfault.bytes_committed -=
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min_t(size_t, bcnt,
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pfault->mpfault.bytes_committed);
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continue;
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}
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ret = pagefault_single_data_segment(qp, pfault, key, io_virt,
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bcnt, bytes_mapped);
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if (ret < 0)
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break;
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npages += ret;
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}
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return ret < 0 ? ret : npages;
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}
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/*
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* Parse initiator WQE. Advances the wqe pointer to point at the
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* scatter-gather list, and set wqe_end to the end of the WQE.
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*/
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static int mlx5_ib_mr_initiator_pfault_handler(
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struct mlx5_ib_qp *qp, struct mlx5_ib_pfault *pfault,
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void **wqe, void **wqe_end, int wqe_length)
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{
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struct mlx5_ib_dev *dev = to_mdev(qp->ibqp.pd->device);
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struct mlx5_wqe_ctrl_seg *ctrl = *wqe;
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u16 wqe_index = pfault->mpfault.wqe.wqe_index;
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unsigned ds, opcode;
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#if defined(DEBUG)
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u32 ctrl_wqe_index, ctrl_qpn;
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#endif
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ds = be32_to_cpu(ctrl->qpn_ds) & MLX5_WQE_CTRL_DS_MASK;
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if (ds * MLX5_WQE_DS_UNITS > wqe_length) {
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mlx5_ib_err(dev, "Unable to read the complete WQE. ds = 0x%x, ret = 0x%x\n",
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ds, wqe_length);
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return -EFAULT;
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}
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if (ds == 0) {
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mlx5_ib_err(dev, "Got WQE with zero DS. wqe_index=%x, qpn=%x\n",
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wqe_index, qp->mqp.qpn);
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return -EFAULT;
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}
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#if defined(DEBUG)
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ctrl_wqe_index = (be32_to_cpu(ctrl->opmod_idx_opcode) &
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MLX5_WQE_CTRL_WQE_INDEX_MASK) >>
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MLX5_WQE_CTRL_WQE_INDEX_SHIFT;
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if (wqe_index != ctrl_wqe_index) {
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mlx5_ib_err(dev, "Got WQE with invalid wqe_index. wqe_index=0x%x, qpn=0x%x ctrl->wqe_index=0x%x\n",
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wqe_index, qp->mqp.qpn,
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ctrl_wqe_index);
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return -EFAULT;
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}
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ctrl_qpn = (be32_to_cpu(ctrl->qpn_ds) & MLX5_WQE_CTRL_QPN_MASK) >>
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MLX5_WQE_CTRL_QPN_SHIFT;
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if (qp->mqp.qpn != ctrl_qpn) {
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mlx5_ib_err(dev, "Got WQE with incorrect QP number. wqe_index=0x%x, qpn=0x%x ctrl->qpn=0x%x\n",
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wqe_index, qp->mqp.qpn,
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ctrl_qpn);
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return -EFAULT;
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}
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#endif /* DEBUG */
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*wqe_end = *wqe + ds * MLX5_WQE_DS_UNITS;
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*wqe += sizeof(*ctrl);
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opcode = be32_to_cpu(ctrl->opmod_idx_opcode) &
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MLX5_WQE_CTRL_OPCODE_MASK;
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switch (qp->ibqp.qp_type) {
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case IB_QPT_RC:
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switch (opcode) {
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case MLX5_OPCODE_SEND:
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case MLX5_OPCODE_SEND_IMM:
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case MLX5_OPCODE_SEND_INVAL:
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if (!(dev->odp_caps.per_transport_caps.rc_odp_caps &
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IB_ODP_SUPPORT_SEND))
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goto invalid_transport_or_opcode;
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break;
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case MLX5_OPCODE_RDMA_WRITE:
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case MLX5_OPCODE_RDMA_WRITE_IMM:
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if (!(dev->odp_caps.per_transport_caps.rc_odp_caps &
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IB_ODP_SUPPORT_WRITE))
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goto invalid_transport_or_opcode;
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*wqe += sizeof(struct mlx5_wqe_raddr_seg);
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break;
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case MLX5_OPCODE_RDMA_READ:
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if (!(dev->odp_caps.per_transport_caps.rc_odp_caps &
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IB_ODP_SUPPORT_READ))
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goto invalid_transport_or_opcode;
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*wqe += sizeof(struct mlx5_wqe_raddr_seg);
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break;
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default:
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goto invalid_transport_or_opcode;
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}
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break;
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case IB_QPT_UD:
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switch (opcode) {
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case MLX5_OPCODE_SEND:
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case MLX5_OPCODE_SEND_IMM:
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if (!(dev->odp_caps.per_transport_caps.ud_odp_caps &
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IB_ODP_SUPPORT_SEND))
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goto invalid_transport_or_opcode;
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*wqe += sizeof(struct mlx5_wqe_datagram_seg);
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break;
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default:
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goto invalid_transport_or_opcode;
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}
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break;
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default:
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invalid_transport_or_opcode:
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mlx5_ib_err(dev, "ODP fault on QP of an unsupported opcode or transport. transport: 0x%x opcode: 0x%x.\n",
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qp->ibqp.qp_type, opcode);
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return -EFAULT;
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}
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return 0;
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}
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/*
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* Parse responder WQE. Advances the wqe pointer to point at the
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* scatter-gather list, and set wqe_end to the end of the WQE.
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*/
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static int mlx5_ib_mr_responder_pfault_handler(
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struct mlx5_ib_qp *qp, struct mlx5_ib_pfault *pfault,
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void **wqe, void **wqe_end, int wqe_length)
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{
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struct mlx5_ib_dev *dev = to_mdev(qp->ibqp.pd->device);
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struct mlx5_ib_wq *wq = &qp->rq;
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int wqe_size = 1 << wq->wqe_shift;
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if (qp->ibqp.srq) {
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mlx5_ib_err(dev, "ODP fault on SRQ is not supported\n");
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return -EFAULT;
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}
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if (qp->wq_sig) {
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mlx5_ib_err(dev, "ODP fault with WQE signatures is not supported\n");
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return -EFAULT;
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}
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if (wqe_size > wqe_length) {
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mlx5_ib_err(dev, "Couldn't read all of the receive WQE's content\n");
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return -EFAULT;
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}
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switch (qp->ibqp.qp_type) {
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case IB_QPT_RC:
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if (!(dev->odp_caps.per_transport_caps.rc_odp_caps &
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IB_ODP_SUPPORT_RECV))
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goto invalid_transport_or_opcode;
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break;
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default:
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invalid_transport_or_opcode:
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mlx5_ib_err(dev, "ODP fault on QP of an unsupported transport. transport: 0x%x\n",
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qp->ibqp.qp_type);
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return -EFAULT;
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}
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*wqe_end = *wqe + wqe_size;
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return 0;
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}
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static void mlx5_ib_mr_wqe_pfault_handler(struct mlx5_ib_qp *qp,
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struct mlx5_ib_pfault *pfault)
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{
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struct mlx5_ib_dev *dev = to_mdev(qp->ibqp.pd->device);
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int ret;
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void *wqe, *wqe_end;
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u32 bytes_mapped, total_wqe_bytes;
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char *buffer = NULL;
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int resume_with_error = 0;
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u16 wqe_index = pfault->mpfault.wqe.wqe_index;
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int requestor = pfault->mpfault.flags & MLX5_PFAULT_REQUESTOR;
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buffer = (char *)__get_free_page(GFP_KERNEL);
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if (!buffer) {
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mlx5_ib_err(dev, "Error allocating memory for IO page fault handling.\n");
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resume_with_error = 1;
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goto resolve_page_fault;
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}
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ret = mlx5_ib_read_user_wqe(qp, requestor, wqe_index, buffer,
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PAGE_SIZE);
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if (ret < 0) {
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mlx5_ib_err(dev, "Failed reading a WQE following page fault, error=%x, wqe_index=%x, qpn=%x\n",
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-ret, wqe_index, qp->mqp.qpn);
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resume_with_error = 1;
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goto resolve_page_fault;
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}
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wqe = buffer;
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if (requestor)
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ret = mlx5_ib_mr_initiator_pfault_handler(qp, pfault, &wqe,
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&wqe_end, ret);
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else
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ret = mlx5_ib_mr_responder_pfault_handler(qp, pfault, &wqe,
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&wqe_end, ret);
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if (ret < 0) {
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resume_with_error = 1;
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goto resolve_page_fault;
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}
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if (wqe >= wqe_end) {
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mlx5_ib_err(dev, "ODP fault on invalid WQE.\n");
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resume_with_error = 1;
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goto resolve_page_fault;
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}
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ret = pagefault_data_segments(qp, pfault, wqe, wqe_end, &bytes_mapped,
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&total_wqe_bytes, !requestor);
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if (ret == -EAGAIN) {
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goto resolve_page_fault;
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} else if (ret < 0 || total_wqe_bytes > bytes_mapped) {
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mlx5_ib_err(dev, "Error getting user pages for page fault. Error: 0x%x\n",
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-ret);
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resume_with_error = 1;
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goto resolve_page_fault;
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}
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resolve_page_fault:
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mlx5_ib_page_fault_resume(qp, pfault, resume_with_error);
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mlx5_ib_dbg(dev, "PAGE FAULT completed. QP 0x%x resume_with_error=%d, flags: 0x%x\n",
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qp->mqp.qpn, resume_with_error, pfault->mpfault.flags);
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free_page((unsigned long)buffer);
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}
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|
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void mlx5_ib_mr_pfault_handler(struct mlx5_ib_qp *qp,
|
||||
struct mlx5_ib_pfault *pfault)
|
||||
{
|
||||
u8 event_subtype = pfault->mpfault.event_subtype;
|
||||
|
||||
switch (event_subtype) {
|
||||
case MLX5_PFAULT_SUBTYPE_WQE:
|
||||
mlx5_ib_mr_wqe_pfault_handler(qp, pfault);
|
||||
break;
|
||||
default:
|
||||
pr_warn("Invalid page fault event subtype: 0x%x\n",
|
||||
event_subtype);
|
||||
|
|
|
|||
|
|
@ -193,7 +193,12 @@ struct mlx5_wqe_ctrl_seg {
|
|||
};
|
||||
|
||||
#define MLX5_WQE_CTRL_DS_MASK 0x3f
|
||||
#define MLX5_WQE_CTRL_QPN_MASK 0xffffff00
|
||||
#define MLX5_WQE_CTRL_QPN_SHIFT 8
|
||||
#define MLX5_WQE_DS_UNITS 16
|
||||
#define MLX5_WQE_CTRL_OPCODE_MASK 0xff
|
||||
#define MLX5_WQE_CTRL_WQE_INDEX_MASK 0x00ffff00
|
||||
#define MLX5_WQE_CTRL_WQE_INDEX_SHIFT 8
|
||||
|
||||
struct mlx5_wqe_xrc_seg {
|
||||
__be32 xrc_srqn;
|
||||
|
|
@ -298,6 +303,8 @@ struct mlx5_wqe_signature_seg {
|
|||
u8 rsvd1[11];
|
||||
};
|
||||
|
||||
#define MLX5_WQE_INLINE_SEG_BYTE_COUNT_MASK 0x3ff
|
||||
|
||||
struct mlx5_wqe_inline_seg {
|
||||
__be32 byte_count;
|
||||
};
|
||||
|
|
|
|||
Loading…
Reference in New Issue