LXR qemu/hw/rdma/vmw/pvrdma_dev

   1/*
   2 * QEMU paravirtual RDMA - Device rings
   3 *
   4 * Copyright (C) 2018 Oracle
   5 * Copyright (C) 2018 Red Hat Inc
   6 *
   7 * Authors:
   8 *     Yuval Shaia <yuval.shaia@oracle.com>
   9 *     Marcel Apfelbaum <marcel@redhat.com>
  10 *
  11 * This work is licensed under the terms of the GNU GPL, version 2 or later.
  12 * See the COPYING file in the top-level directory.
  13 *
  14 */
  15
  16#include "qemu/osdep.h"
  17#include "qemu/cutils.h"
  18#include "hw/pci/pci.h"
  19#include "cpu.h"
  20#include "qemu/cutils.h"
  21
  22#include "trace.h"
  23
  24#include "../rdma_utils.h"
  25#include "pvrdma_dev_ring.h"
  26
  27int pvrdma_ring_init(PvrdmaRing *ring, const char *name, PCIDevice *dev,
  28                     PvrdmaRingState *ring_state, uint32_t max_elems,
  29                     size_t elem_sz, dma_addr_t *tbl, uint32_t npages)
  30{
  31    int i;
  32    int rc = 0;
  33
  34    pstrcpy(ring->name, MAX_RING_NAME_SZ, name);
  35    ring->dev = dev;
  36    ring->ring_state = ring_state;
  37    ring->max_elems = max_elems;
  38    ring->elem_sz = elem_sz;
  39    /* TODO: Give a moment to think if we want to redo driver settings
  40    qatomic_set(&ring->ring_state->prod_tail, 0);
  41    qatomic_set(&ring->ring_state->cons_head, 0);
  42    */
  43    ring->npages = npages;
  44    ring->pages = g_malloc0(npages * sizeof(void *));
  45
  46    for (i = 0; i < npages; i++) {
  47        if (!tbl[i]) {
  48            rdma_error_report("npages=%d but tbl[%d] is NULL", npages, i);
  49            continue;
  50        }
  51
  52        ring->pages[i] = rdma_pci_dma_map(dev, tbl[i], TARGET_PAGE_SIZE);
  53        if (!ring->pages[i]) {
  54            rc = -ENOMEM;
  55            rdma_error_report("Failed to map to page %d in ring %s", i, name);
  56            goto out_free;
  57        }
  58        memset(ring->pages[i], 0, TARGET_PAGE_SIZE);
  59    }
  60
  61    goto out;
  62
  63out_free:
  64    while (i--) {
  65        rdma_pci_dma_unmap(dev, ring->pages[i], TARGET_PAGE_SIZE);
  66    }
  67    g_free(ring->pages);
  68
  69out:
  70    return rc;
  71}
  72
  73void *pvrdma_ring_next_elem_read(PvrdmaRing *ring)
  74{
  75    unsigned int idx, offset;
  76    const uint32_t tail = qatomic_read(&ring->ring_state->prod_tail);
  77    const uint32_t head = qatomic_read(&ring->ring_state->cons_head);
  78
  79    if (tail & ~((ring->max_elems << 1) - 1) ||
  80        head & ~((ring->max_elems << 1) - 1) ||
  81        tail == head) {
  82        trace_pvrdma_ring_next_elem_read_no_data(ring->name);
  83        return NULL;
  84    }
  85
  86    idx = head & (ring->max_elems - 1);
  87    offset = idx * ring->elem_sz;
  88    return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE);
  89}
  90
  91void pvrdma_ring_read_inc(PvrdmaRing *ring)
  92{
  93    uint32_t idx = qatomic_read(&ring->ring_state->cons_head);
  94
  95    idx = (idx + 1) & ((ring->max_elems << 1) - 1);
  96    qatomic_set(&ring->ring_state->cons_head, idx);
  97}
  98
  99void *pvrdma_ring_next_elem_write(PvrdmaRing *ring)
 100{
 101    unsigned int idx, offset;
 102    const uint32_t tail = qatomic_read(&ring->ring_state->prod_tail);
 103    const uint32_t head = qatomic_read(&ring->ring_state->cons_head);
 104
 105    if (tail & ~((ring->max_elems << 1) - 1) ||
 106        head & ~((ring->max_elems << 1) - 1) ||
 107        tail == (head ^ ring->max_elems)) {
 108        rdma_error_report("CQ is full");
 109        return NULL;
 110    }
 111
 112    idx = tail & (ring->max_elems - 1);
 113    offset = idx * ring->elem_sz;
 114    return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE);
 115}
 116
 117void pvrdma_ring_write_inc(PvrdmaRing *ring)
 118{
 119    uint32_t idx = qatomic_read(&ring->ring_state->prod_tail);
 120
 121    idx = (idx + 1) & ((ring->max_elems << 1) - 1);
 122    qatomic_set(&ring->ring_state->prod_tail, idx);
 123}
 124
 125void pvrdma_ring_free(PvrdmaRing *ring)
 126{
 127    if (!ring) {
 128        return;
 129    }
 130
 131    if (!ring->pages) {
 132        return;
 133    }
 134
 135    while (ring->npages--) {
 136        rdma_pci_dma_unmap(ring->dev, ring->pages[ring->npages],
 137                           TARGET_PAGE_SIZE);
 138    }
 139
 140    g_free(ring->pages);
 141    ring->pages = NULL;
 142}
 143