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     unsigned int idx = 0, offset;
  77
  78     /*
  79     pr_dbg("%s: t=%d, h=%d\n", ring->name, ring->ring_state->prod_tail,
  80            ring->ring_state->cons_head);
  81     */
  82
  83     if (!pvrdma_idx_ring_has_data(ring->ring_state, ring->max_elems, &idx)) {
  84         pr_dbg("No more data in ring\n");
  85         return NULL;
  86     }
  87
  88     offset = idx * ring->elem_sz;
  89     /*
  90     pr_dbg("idx=%d\n", idx);
  91     pr_dbg("offset=%d\n", offset);
  92     */
  93     return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE);
  94 }
  95
  96 void pvrdma_ring_read_inc(PvrdmaRing *ring)
  97 {
  98     pvrdma_idx_ring_inc(&ring->ring_state->cons_head, ring->max_elems);
  99     /*
 100     pr_dbg("%s: t=%d, h=%d, m=%ld\n", ring->name,
 101            ring->ring_state->prod_tail, ring->ring_state->cons_head,
 102            ring->max_elems);
 103     */
 104 }
 105
 106 void *pvrdma_ring_next_elem_write(PvrdmaRing *ring)
 107 {
 108     unsigned int idx, offset, tail;
 109
 110     /*
 111     pr_dbg("%s: t=%d, h=%d\n", ring->name, ring->ring_state->prod_tail,
 112            ring->ring_state->cons_head);
 113     */
 114
 115     if (!pvrdma_idx_ring_has_space(ring->ring_state, ring->max_elems, &tail)) {
 116         pr_dbg("CQ is full\n");
 117         return NULL;
 118     }
 119
 120     idx = pvrdma_idx(&ring->ring_state->prod_tail, ring->max_elems);
 121     /* TODO: tail == idx */
 122
 123     offset = idx * ring->elem_sz;
 124     return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE);
 125 }
 126
 127 void pvrdma_ring_write_inc(PvrdmaRing *ring)
 128 {
 129     pvrdma_idx_ring_inc(&ring->ring_state->prod_tail, ring->max_elems);
 130     /*
 131     pr_dbg("%s: t=%d, h=%d, m=%ld\n", ring->name,
 132            ring->ring_state->prod_tail, ring->ring_state->cons_head,
 133            ring->max_elems);
 134     */
 135 }
 136
 137 void pvrdma_ring_free(PvrdmaRing *ring)
 138 {
 139     if (!ring) {
 140         return;
 141     }
 142
 143     if (!ring->pages) {
 144         return;
 145     }
 146
 147     pr_dbg("ring->npages=%d\n", ring->npages);
 148     while (ring->npages--) {
 149         rdma_pci_dma_unmap(ring->dev, ring->pages[ring->npages],
 150                            TARGET_PAGE_SIZE);
 151     }
 152
 153     g_free(ring->pages);
 154     ring->pages = NULL;
 155 }