rte_idxd_rawdev_fns.h

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/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2021 Intel Corporation
 */
#ifndef _RTE_IDXD_RAWDEV_FNS_H_
#define _RTE_IDXD_RAWDEV_FNS_H_

#include <stdint.h>
#include <rte_errno.h>

/*
 * Defines used in the data path for interacting with IDXD hardware.
 */
#define IDXD_CMD_OP_SHIFT 24
enum rte_idxd_ops {
    idxd_op_nop = 0,
    idxd_op_batch,
    idxd_op_drain,
    idxd_op_memmove,
    idxd_op_fill
};

#define IDXD_FLAG_FENCE                 (1 << 0)
#define IDXD_FLAG_COMPLETION_ADDR_VALID (1 << 2)
#define IDXD_FLAG_REQUEST_COMPLETION    (1 << 3)
#define IDXD_FLAG_CACHE_CONTROL         (1 << 8)

#define IOAT_COMP_UPDATE_SHIFT  3
#define IOAT_CMD_OP_SHIFT   24
enum rte_ioat_ops {
    ioat_op_copy = 0,   /* Standard DMA Operation */
    ioat_op_fill        /* Block Fill */
};

struct rte_idxd_hw_desc {
    uint32_t pasid;
    uint32_t op_flags;
    rte_iova_t completion;

    RTE_STD_C11
    union {
        rte_iova_t src;      /* source address for copy ops etc. */
        rte_iova_t desc_addr; /* descriptor pointer for batch */
    };
    rte_iova_t dst;

    uint32_t size;    /* length of data for op, or batch size */

    uint16_t intr_handle; /* completion interrupt handle */

    /* remaining 26 bytes are reserved */
    uint16_t __reserved[13];
} __rte_aligned(64);

struct rte_idxd_completion {
    uint8_t status;
    uint8_t result;
    /* 16-bits pad here */
    uint32_t completed_size; /* data length, or descriptors for batch */

    rte_iova_t fault_address;
    uint32_t invalid_flags;
} __rte_aligned(32);

struct rte_idxd_user_hdl {
    uint64_t src;
    uint64_t dst;
};

struct rte_idxd_rawdev {
    enum rte_ioat_dev_type type;
    struct rte_ioat_xstats xstats;

    void *portal; /* address to write the batch descriptor */

    struct rte_ioat_rawdev_config cfg;
    rte_iova_t desc_iova; /* base address of desc ring, needed for completions */

    /* counters to track the batches */
    unsigned short max_batches;
    unsigned short batch_idx_read;
    unsigned short batch_idx_write;
    unsigned short *batch_idx_ring; /* store where each batch ends */

    /* track descriptors and handles */
    unsigned short desc_ring_mask;
    unsigned short hdls_avail; /* handles for ops completed */
    unsigned short hdls_read; /* the read pointer for hdls/desc rings */
    unsigned short batch_start; /* start+size == write pointer for hdls/desc */
    unsigned short batch_size;

    struct rte_idxd_hw_desc *desc_ring;
    struct rte_idxd_user_hdl *hdl_ring;
    /* flags to indicate handle validity. Kept separate from ring, to avoid
     * using 8 bytes per flag. Upper 8 bits holds error code if any.
     */
    uint16_t *hdl_ring_flags;
};

#define RTE_IDXD_HDL_NORMAL     0
#define RTE_IDXD_HDL_INVALID    (1 << 0) /* no handle stored for this element */
#define RTE_IDXD_HDL_OP_FAILED  (1 << 1) /* return failure for this one */
#define RTE_IDXD_HDL_OP_SKIPPED (1 << 2) /* this op was skipped */

static __rte_always_inline uint16_t
__idxd_burst_capacity(int dev_id)
{
    struct rte_idxd_rawdev *idxd =
            (struct rte_idxd_rawdev *)rte_rawdevs[dev_id].dev_private;
    uint16_t write_idx = idxd->batch_start + idxd->batch_size;
    uint16_t used_space, free_space;

    /* Check for space in the batch ring */
    if ((idxd->batch_idx_read == 0 && idxd->batch_idx_write == idxd->max_batches) ||
            idxd->batch_idx_write + 1 == idxd->batch_idx_read)
        return 0;

    /* for descriptors, check for wrap-around on write but not read */
    if (idxd->hdls_read > write_idx)
        write_idx += idxd->desc_ring_mask + 1;
    used_space = write_idx - idxd->hdls_read;

    /* Return amount of free space in the descriptor ring
     * subtract 1 for space for batch descriptor and 1 for possible null desc
     */
    free_space = idxd->desc_ring_mask - used_space;
    if (free_space < 2)
        return 0;
    return free_space - 2;
}

static __rte_always_inline rte_iova_t
__desc_idx_to_iova(struct rte_idxd_rawdev *idxd, uint16_t n)
{
    return idxd->desc_iova + (n * sizeof(struct rte_idxd_hw_desc));
}

static __rte_always_inline int
__idxd_write_desc(int dev_id,
        const uint32_t op_flags,
        const rte_iova_t src,
        const rte_iova_t dst,
        const uint32_t size,
        const struct rte_idxd_user_hdl *hdl)
{
    struct rte_idxd_rawdev *idxd =
            (struct rte_idxd_rawdev *)rte_rawdevs[dev_id].dev_private;
    uint16_t write_idx = idxd->batch_start + idxd->batch_size;
    uint16_t mask = idxd->desc_ring_mask;

    /* first check batch ring space then desc ring space */
    if ((idxd->batch_idx_read == 0 && idxd->batch_idx_write == idxd->max_batches) ||
            idxd->batch_idx_write + 1 == idxd->batch_idx_read)
        goto failed;
    /* for descriptor ring, we always need a slot for batch completion */
    if (((write_idx + 2) & mask) == idxd->hdls_read ||
            ((write_idx + 1) & mask) == idxd->hdls_read)
        goto failed;

    /* write desc and handle. Note, descriptors don't wrap */
    idxd->desc_ring[write_idx].pasid = 0;
    idxd->desc_ring[write_idx].op_flags = op_flags | IDXD_FLAG_COMPLETION_ADDR_VALID;
    idxd->desc_ring[write_idx].completion = __desc_idx_to_iova(idxd, write_idx & mask);
    idxd->desc_ring[write_idx].src = src;
    idxd->desc_ring[write_idx].dst = dst;
    idxd->desc_ring[write_idx].size = size;

    if (hdl == NULL)
        idxd->hdl_ring_flags[write_idx & mask] = RTE_IDXD_HDL_INVALID;
    else
        idxd->hdl_ring[write_idx & mask] = *hdl;
    idxd->batch_size++;

    idxd->xstats.enqueued++;

    rte_prefetch0_write(&idxd->desc_ring[write_idx + 1]);
    return 1;

failed:
    idxd->xstats.enqueue_failed++;
    rte_errno = ENOSPC;
    return 0;
}

static __rte_always_inline int
__idxd_enqueue_fill(int dev_id, uint64_t pattern, rte_iova_t dst,
        unsigned int length, uintptr_t dst_hdl)
{
    const struct rte_idxd_user_hdl hdl = {
            .dst = dst_hdl
    };
    return __idxd_write_desc(dev_id,
            (idxd_op_fill << IDXD_CMD_OP_SHIFT) | IDXD_FLAG_CACHE_CONTROL,
            pattern, dst, length, &hdl);
}

static __rte_always_inline int
__idxd_enqueue_copy(int dev_id, rte_iova_t src, rte_iova_t dst,
        unsigned int length, uintptr_t src_hdl, uintptr_t dst_hdl)
{
    const struct rte_idxd_user_hdl hdl = {
            .src = src_hdl,
            .dst = dst_hdl
    };
    return __idxd_write_desc(dev_id,
            (idxd_op_memmove << IDXD_CMD_OP_SHIFT) | IDXD_FLAG_CACHE_CONTROL,
            src, dst, length, &hdl);
}

static __rte_always_inline int
__idxd_enqueue_nop(int dev_id)
{
    /* only op field needs filling - zero src, dst and length */
    return __idxd_write_desc(dev_id, idxd_op_nop << IDXD_CMD_OP_SHIFT,
            0, 0, 0, NULL);
}

static __rte_always_inline int
__idxd_fence(int dev_id)
{
    /* only op field needs filling - zero src, dst and length */
    return __idxd_write_desc(dev_id, IDXD_FLAG_FENCE, 0, 0, 0, NULL);
}

static __rte_always_inline void
__idxd_movdir64b(volatile void *dst, const struct rte_idxd_hw_desc *src)
{
    asm volatile (".byte 0x66, 0x0f, 0x38, 0xf8, 0x02"
            :
            : "a" (dst), "d" (src)
            : "memory");
}

static __rte_always_inline int
__idxd_perform_ops(int dev_id)
{
    struct rte_idxd_rawdev *idxd =
            (struct rte_idxd_rawdev *)rte_rawdevs[dev_id].dev_private;

    if (!idxd->cfg.no_prefetch_completions)
        rte_prefetch1(&idxd->desc_ring[idxd->batch_idx_ring[idxd->batch_idx_read]]);

    if (idxd->batch_size == 0)
        return 0;

    if (idxd->batch_size == 1)
        /* use a NOP as a null descriptor, so batch_size >= 2 */
        if (__idxd_enqueue_nop(dev_id) != 1)
            return -1;

    /* write completion beyond last desc in the batch */
    uint16_t comp_idx = (idxd->batch_start + idxd->batch_size) & idxd->desc_ring_mask;
    *((uint64_t *)&idxd->desc_ring[comp_idx]) = 0; /* zero start of desc */
    idxd->hdl_ring_flags[comp_idx] = RTE_IDXD_HDL_INVALID;

    const struct rte_idxd_hw_desc batch_desc = {
            .op_flags = (idxd_op_batch << IDXD_CMD_OP_SHIFT) |
                IDXD_FLAG_COMPLETION_ADDR_VALID |
                IDXD_FLAG_REQUEST_COMPLETION,
            .desc_addr = __desc_idx_to_iova(idxd, idxd->batch_start),
            .completion = __desc_idx_to_iova(idxd, comp_idx),
            .size = idxd->batch_size,
    };

    _mm_sfence(); /* fence before writing desc to device */
    __idxd_movdir64b(idxd->portal, &batch_desc);
    idxd->xstats.started += idxd->batch_size;

    idxd->batch_start += idxd->batch_size + 1;
    idxd->batch_start &= idxd->desc_ring_mask;
    idxd->batch_size = 0;

    idxd->batch_idx_ring[idxd->batch_idx_write++] = comp_idx;
    if (idxd->batch_idx_write > idxd->max_batches)
        idxd->batch_idx_write = 0;

    return 0;
}

static __rte_always_inline int
__idxd_completed_ops(int dev_id, uint8_t max_ops, uint32_t *status, uint8_t *num_unsuccessful,
        uintptr_t *src_hdls, uintptr_t *dst_hdls)
{
    struct rte_idxd_rawdev *idxd =
            (struct rte_idxd_rawdev *)rte_rawdevs[dev_id].dev_private;
    unsigned short n, h_idx;

    while (idxd->batch_idx_read != idxd->batch_idx_write) {
        uint16_t idx_to_chk = idxd->batch_idx_ring[idxd->batch_idx_read];
        volatile struct rte_idxd_completion *comp_to_chk =
                (struct rte_idxd_completion *)&idxd->desc_ring[idx_to_chk];
        uint8_t batch_status = comp_to_chk->status;
        if (batch_status == 0)
            break;
        comp_to_chk->status = 0;
        if (unlikely(batch_status > 1)) {
            /* error occurred somewhere in batch, start where last checked */
            uint16_t desc_count = comp_to_chk->completed_size;
            uint16_t batch_start = idxd->hdls_avail;
            uint16_t batch_end = idx_to_chk;

            if (batch_start > batch_end)
                batch_end += idxd->desc_ring_mask + 1;
            /* go through each batch entry and see status */
            for (n = 0; n < desc_count; n++) {
                uint16_t idx = (batch_start + n) & idxd->desc_ring_mask;
                volatile struct rte_idxd_completion *comp =
                    (struct rte_idxd_completion *)&idxd->desc_ring[idx];
                if (comp->status != 0 &&
                        idxd->hdl_ring_flags[idx] == RTE_IDXD_HDL_NORMAL) {
                    idxd->hdl_ring_flags[idx] = RTE_IDXD_HDL_OP_FAILED;
                    idxd->hdl_ring_flags[idx] |= (comp->status << 8);
                    comp->status = 0; /* clear error for next time */
                }
            }
            /* if batch is incomplete, mark rest as skipped */
            for ( ; n < batch_end - batch_start; n++) {
                uint16_t idx = (batch_start + n) & idxd->desc_ring_mask;
                if (idxd->hdl_ring_flags[idx] == RTE_IDXD_HDL_NORMAL)
                    idxd->hdl_ring_flags[idx] = RTE_IDXD_HDL_OP_SKIPPED;
            }
        }
        /* avail points to one after the last one written */
        idxd->hdls_avail = (idx_to_chk + 1) & idxd->desc_ring_mask;
        idxd->batch_idx_read++;
        if (idxd->batch_idx_read > idxd->max_batches)
            idxd->batch_idx_read = 0;
    }

    n = 0;
    h_idx = idxd->hdls_read;
    while (h_idx != idxd->hdls_avail) {
        uint16_t flag = idxd->hdl_ring_flags[h_idx];
        if (flag != RTE_IDXD_HDL_INVALID) {
            if (!idxd->cfg.hdls_disable) {
                src_hdls[n] = idxd->hdl_ring[h_idx].src;
                dst_hdls[n] = idxd->hdl_ring[h_idx].dst;
            }
            if (unlikely(flag != RTE_IDXD_HDL_NORMAL)) {
                if (status != NULL)
                    status[n] = flag == RTE_IDXD_HDL_OP_SKIPPED ?
                            RTE_IOAT_OP_SKIPPED :
                            /* failure case, return err code */
                            idxd->hdl_ring_flags[h_idx] >> 8;
                if (num_unsuccessful != NULL)
                    *num_unsuccessful += 1;
            }
            n++;
        }
        idxd->hdl_ring_flags[h_idx] = RTE_IDXD_HDL_NORMAL;
        if (++h_idx > idxd->desc_ring_mask)
            h_idx = 0;
        if (n >= max_ops)
            break;
    }

    /* skip over any remaining blank elements, e.g. batch completion */
    while (idxd->hdl_ring_flags[h_idx] == RTE_IDXD_HDL_INVALID && h_idx != idxd->hdls_avail) {
        idxd->hdl_ring_flags[h_idx] = RTE_IDXD_HDL_NORMAL;
        if (++h_idx > idxd->desc_ring_mask)
            h_idx = 0;
    }
    idxd->hdls_read = h_idx;

    idxd->xstats.completed += n;
    return n;
}

#endif