hw/rdma/vmw/pvrdma_dev_ring.c

   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 "standard-headers/drivers/infiniband/hw/vmw_pvrdma/pvrdma_ring.h"
  26 #include "pvrdma_dev_ring.h"
  27
  28 int pvrdma_ring_init(PvrdmaRing *ring, const char *name, PCIDevice *dev,
  29                      struct pvrdma_ring *ring_state, uint32_t max_elems,
  30                      size_t elem_sz, dma_addr_t *tbl, uint32_t npages)
  31 {
  32     int i;
  33     int rc = 0;
  34
  35     pstrcpy(ring->name, MAX_RING_NAME_SZ, name);
  36     ring->dev = dev;
  37     ring->ring_state = ring_state;
  38     ring->max_elems = max_elems;
  39     ring->elem_sz = elem_sz;
  40     /* TODO: Give a moment to think if we want to redo driver settings
  41     atomic_set(&ring->ring_state->prod_tail, 0);
  42     atomic_set(&ring->ring_state->cons_head, 0);
  43     */
  44     ring->npages = npages;
  45     ring->pages = g_malloc(npages * sizeof(void *));
  46
  47     for (i = 0; i < npages; i++) {
  48         if (!tbl[i]) {
  49             rdma_error_report("npages=%d but tbl[%d] is NULL", npages, i);
  50             continue;
  51         }
  52
  53         ring->pages[i] = rdma_pci_dma_map(dev, tbl[i], TARGET_PAGE_SIZE);
  54         if (!ring->pages[i]) {
  55             rc = -ENOMEM;
  56             rdma_error_report("Failed to map to page %d in ring %s", i, name);
  57             goto out_free;
  58         }
  59         memset(ring->pages[i], 0, TARGET_PAGE_SIZE);
  60     }
  61
  62     goto out;
  63
  64 out_free:
  65     while (i--) {
  66         rdma_pci_dma_unmap(dev, ring->pages[i], TARGET_PAGE_SIZE);
  67     }
  68     g_free(ring->pages);
  69
  70 out:
  71     return rc;
  72 }
  73
  74 void *pvrdma_ring_next_elem_read(PvrdmaRing *ring)
  75 {
  76     int e;
  77     unsigned int idx = 0, offset;
  78
  79     e = pvrdma_idx_ring_has_data(ring->ring_state, ring->max_elems, &idx);
  80     if (e <= 0) {
  81         trace_pvrdma_ring_next_elem_read_no_data(ring->name);
  82         return NULL;
  83     }
  84
  85     offset = idx * ring->elem_sz;
  86     return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE);
  87 }
  88
  89 void pvrdma_ring_read_inc(PvrdmaRing *ring)
  90 {
  91     pvrdma_idx_ring_inc(&ring->ring_state->cons_head, ring->max_elems);
  92 }
  93
  94 void *pvrdma_ring_next_elem_write(PvrdmaRing *ring)
  95 {
  96     int idx;
  97     unsigned int offset, tail;
  98
  99     idx = pvrdma_idx_ring_has_space(ring->ring_state, ring->max_elems, &tail);
 100     if (idx <= 0) {
 101         rdma_error_report("CQ is full");
 102         return NULL;
 103     }
 104
 105     idx = pvrdma_idx(&ring->ring_state->prod_tail, ring->max_elems);
 106     if (idx < 0 || tail != idx) {
 107         rdma_error_report("Invalid idx %d", idx);
 108         return NULL;
 109     }
 110
 111     offset = idx * ring->elem_sz;
 112     return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE);
 113 }
 114
 115 void pvrdma_ring_write_inc(PvrdmaRing *ring)
 116 {
 117     pvrdma_idx_ring_inc(&ring->ring_state->prod_tail, ring->max_elems);
 118 }
 119
 120 void pvrdma_ring_free(PvrdmaRing *ring)
 121 {
 122     if (!ring) {
 123         return;
 124     }
 125
 126     if (!ring->pages) {
 127         return;
 128     }
 129
 130     while (ring->npages--) {
 131         rdma_pci_dma_unmap(ring->dev, ring->pages[ring->npages],
 132                            TARGET_PAGE_SIZE);
 133     }
 134
 135     g_free(ring->pages);
 136     ring->pages = NULL;
 137 }