120 lines
2.6 KiB
C
120 lines
2.6 KiB
C
/*
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* SHARED BUFFER
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*
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* Copyright (C) 2017 Intel Corporation. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Li Fei <fei1.li@intel.com>
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*
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*/
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#include <hypervisor.h>
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static inline bool sbuf_is_empty(const struct shared_buf *sbuf)
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{
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return (sbuf->head == sbuf->tail);
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}
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uint32_t sbuf_next_ptr(uint32_t pos_arg,
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uint32_t span, uint32_t scope)
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{
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uint32_t pos = pos_arg;
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pos += span;
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pos = (pos >= scope) ? (pos - scope) : pos;
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return pos;
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}
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uint32_t sbuf_get(struct shared_buf *sbuf, uint8_t *data)
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{
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const void *from;
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uint32_t ele_size;
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stac();
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if (sbuf_is_empty(sbuf)) {
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clac();
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/* no data available */
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return 0;
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}
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from = (void *)sbuf + SBUF_HEAD_SIZE + sbuf->head;
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(void)memcpy_s((void *)data, sbuf->ele_size, from, sbuf->ele_size);
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sbuf->head = sbuf_next_ptr(sbuf->head, sbuf->ele_size, sbuf->size);
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ele_size = sbuf->ele_size;
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clac();
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return ele_size;
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}
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/**
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* The high caller should guarantee each time there must have
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* sbuf->ele_size data can be write form data and this function
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* should guarantee execution atomically.
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*
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* flag:
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* If OVERWRITE_EN set, buf can store (ele_num - 1) elements at most.
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* Should use lock to guarantee that only one read or write at
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* the same time.
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* if OVERWRITE_EN not set, buf can store (ele_num - 1) elements
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* at most. Shouldn't modify the sbuf->head.
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*
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* return:
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* ele_size: write succeeded.
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* 0: no write, buf is full
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* negative: failed.
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*/
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uint32_t sbuf_put(struct shared_buf *sbuf, uint8_t *data)
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{
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void *to;
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uint32_t next_tail;
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uint32_t ele_size;
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bool trigger_overwrite = false;
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stac();
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next_tail = sbuf_next_ptr(sbuf->tail, sbuf->ele_size, sbuf->size);
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/* if this write would trigger overrun */
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if (next_tail == sbuf->head) {
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/* accumulate overrun count if necessary */
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sbuf->overrun_cnt += sbuf->flags & OVERRUN_CNT_EN;
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if ((sbuf->flags & OVERWRITE_EN) == 0U) {
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/* if not enable over write, return here. */
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clac();
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return 0;
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}
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trigger_overwrite = true;
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}
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to = (void *)sbuf + SBUF_HEAD_SIZE + sbuf->tail;
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(void)memcpy_s(to, sbuf->ele_size, data, sbuf->ele_size);
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if (trigger_overwrite) {
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sbuf->head = sbuf_next_ptr(sbuf->head,
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sbuf->ele_size, sbuf->size);
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}
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sbuf->tail = next_tail;
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ele_size = sbuf->ele_size;
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clac();
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return ele_size;
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}
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int32_t sbuf_share_setup(uint16_t pcpu_id, uint32_t sbuf_id, uint64_t *hva)
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{
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if ((pcpu_id >= phys_cpu_num) ||
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(sbuf_id >= ACRN_SBUF_ID_MAX)) {
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return -EINVAL;
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}
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per_cpu(sbuf, pcpu_id)[sbuf_id] = hva;
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pr_info("%s share sbuf for pCPU[%u] with sbuf_id[%u] setup successfully",
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__func__, pcpu_id, sbuf_id);
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return 0;
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}
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