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 "hw/pci/pci.h"
  18 #include "cpu.h"
  19
  20 #include "../rdma_utils.h"
  21 #include "standard-headers/drivers/infiniband/hw/vmw_pvrdma/pvrdma_ring.h"
  22 #include "pvrdma_dev_ring.h"
  23
  24 int pvrdma_ring_init(PvrdmaRing *ring, const char *name, PCIDevice *dev,
  25                      struct pvrdma_ring *ring_state, uint32_t max_elems,
  26                      size_t elem_sz, dma_addr_t *tbl, uint32_t npages)
  27 {
  28     int i;
  29     int rc = 0;
  30
  31     strncpy(ring->name, name, MAX_RING_NAME_SZ);
  32     ring->name[MAX_RING_NAME_SZ - 1] = 0;
  33     pr_dbg("Initializing %s ring\n", ring->name);
  34     ring->dev = dev;
  35     ring->ring_state = ring_state;
  36     ring->max_elems = max_elems;
  37     ring->elem_sz = elem_sz;
  38     pr_dbg("ring->elem_sz=%zu\n", ring->elem_sz);
  39     pr_dbg("npages=%d\n", npages);
  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             pr_err("npages=%ld but tbl[%d] is NULL\n", (long)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             pr_dbg("Failed to map to page %d\n", i);
  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         pr_dbg("No more data in ring\n");
  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     pr_dbg("%s: t=%d, h=%d, m=%ld\n", ring->name,
  94            ring->ring_state->prod_tail, ring->ring_state->cons_head,
  95            ring->max_elems);
  96     */
  97 }
  98
  99 void *pvrdma_ring_next_elem_write(PvrdmaRing *ring)
 100 {
 101     int idx;
 102     unsigned int offset, tail;
 103
 104     idx = pvrdma_idx_ring_has_space(ring->ring_state, ring->max_elems, &tail);
 105     if (idx <= 0) {
 106         pr_dbg("CQ is full\n");
 107         return NULL;
 108     }
 109
 110     idx = pvrdma_idx(&ring->ring_state->prod_tail, ring->max_elems);
 111     if (idx < 0 || tail != idx) {
 112         pr_dbg("invalid idx\n");
 113         return NULL;
 114     }
 115
 116     offset = idx * ring->elem_sz;
 117     return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE);
 118 }
 119
 120 void pvrdma_ring_write_inc(PvrdmaRing *ring)
 121 {
 122     pvrdma_idx_ring_inc(&ring->ring_state->prod_tail, ring->max_elems);
 123     /*
 124     pr_dbg("%s: t=%d, h=%d, m=%ld\n", ring->name,
 125            ring->ring_state->prod_tail, ring->ring_state->cons_head,
 126            ring->max_elems);
 127     */
 128 }
 129
 130 void pvrdma_ring_free(PvrdmaRing *ring)
 131 {
 132     if (!ring) {
 133         return;
 134     }
 135
 136     if (!ring->pages) {
 137         return;
 138     }
 139
 140     pr_dbg("ring->npages=%d\n", ring->npages);
 141     while (ring->npages--) {
 142         rdma_pci_dma_unmap(ring->dev, ring->pages[ring->npages],
 143                            TARGET_PAGE_SIZE);
 144     }
 145
 146     g_free(ring->pages);
 147     ring->pages = NULL;
 148 }