dma-helpers.c

   1 /*
   2  * DMA helper functions
   3  *
   4  * Copyright (c) 2009 Red Hat
   5  *
   6  * This work is licensed under the terms of the GNU General Public License
   7  * (GNU GPL), version 2 or later.
   8  */
   9
  10 #include "sysemu/dma.h"
  11 #include "trace.h"
  12 #include "qemu/range.h"
  13 #include "qemu/thread.h"
  14 #include "qemu/main-loop.h"
  15
  16 /* #define DEBUG_IOMMU */
  17
  18 int dma_memory_set(AddressSpace *as, dma_addr_t addr, uint8_t c, dma_addr_t len)
  19 {
  20     dma_barrier(as, DMA_DIRECTION_FROM_DEVICE);
  21
  22 #define FILLBUF_SIZE 512
  23     uint8_t fillbuf[FILLBUF_SIZE];
  24     int l;
  25     bool error = false;
  26
  27     memset(fillbuf, c, FILLBUF_SIZE);
  28     while (len > 0) {
  29         l = len < FILLBUF_SIZE ? len : FILLBUF_SIZE;
  30         error |= address_space_rw(as, addr, fillbuf, l, true);
  31         len -= l;
  32         addr += l;
  33     }
  34
  35     return error;
  36 }
  37
  38 void qemu_sglist_init(QEMUSGList *qsg, DeviceState *dev, int alloc_hint,
  39                       AddressSpace *as)
  40 {
  41     qsg->sg = g_malloc(alloc_hint * sizeof(ScatterGatherEntry));
  42     qsg->nsg = 0;
  43     qsg->nalloc = alloc_hint;
  44     qsg->size = 0;
  45     qsg->as = as;
  46     qsg->dev = dev;
  47     object_ref(OBJECT(dev));
  48 }
  49
  50 void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len)
  51 {
  52     if (qsg->nsg == qsg->nalloc) {
  53         qsg->nalloc = 2 * qsg->nalloc + 1;
  54         qsg->sg = g_realloc(qsg->sg, qsg->nalloc * sizeof(ScatterGatherEntry));
  55     }
  56     qsg->sg[qsg->nsg].base = base;
  57     qsg->sg[qsg->nsg].len = len;
  58     qsg->size += len;
  59     ++qsg->nsg;
  60 }
  61
  62 void qemu_sglist_destroy(QEMUSGList *qsg)
  63 {
  64     object_unref(OBJECT(qsg->dev));
  65     g_free(qsg->sg);
  66     memset(qsg, 0, sizeof(*qsg));
  67 }
  68
  69 typedef struct {
  70     BlockDriverAIOCB common;
  71     BlockDriverState *bs;
  72     BlockDriverAIOCB *acb;
  73     QEMUSGList *sg;
  74     uint64_t sector_num;
  75     DMADirection dir;
  76     int sg_cur_index;
  77     dma_addr_t sg_cur_byte;
  78     QEMUIOVector iov;
  79     QEMUBH *bh;
  80     DMAIOFunc *io_func;
  81 } DMAAIOCB;
  82
  83 static void dma_bdrv_cb(void *opaque, int ret);
  84
  85 static void reschedule_dma(void *opaque)
  86 {
  87     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
  88
  89     qemu_bh_delete(dbs->bh);
  90     dbs->bh = NULL;
  91     dma_bdrv_cb(dbs, 0);
  92 }
  93
  94 static void continue_after_map_failure(void *opaque)
  95 {
  96     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
  97
  98     dbs->bh = qemu_bh_new(reschedule_dma, dbs);
  99     qemu_bh_schedule(dbs->bh);
 100 }
 101
 102 static void dma_bdrv_unmap(DMAAIOCB *dbs)
 103 {
 104     int i;
 105
 106     for (i = 0; i < dbs->iov.niov; ++i) {
 107         dma_memory_unmap(dbs->sg->as, dbs->iov.iov[i].iov_base,
 108                          dbs->iov.iov[i].iov_len, dbs->dir,
 109                          dbs->iov.iov[i].iov_len);
 110     }
 111     qemu_iovec_reset(&dbs->iov);
 112 }
 113
 114 static void dma_complete(DMAAIOCB *dbs, int ret)
 115 {
 116     trace_dma_complete(dbs, ret, dbs->common.cb);
 117
 118     dma_bdrv_unmap(dbs);
 119     if (dbs->common.cb) {
 120         dbs->common.cb(dbs->common.opaque, ret);
 121     }
 122     qemu_iovec_destroy(&dbs->iov);
 123     if (dbs->bh) {
 124         qemu_bh_delete(dbs->bh);
 125         dbs->bh = NULL;
 126     }
 127     qemu_aio_unref(dbs);
 128 }
 129
 130 static void dma_bdrv_cb(void *opaque, int ret)
 131 {
 132     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
 133     dma_addr_t cur_addr, cur_len;
 134     void *mem;
 135
 136     trace_dma_bdrv_cb(dbs, ret);
 137
 138     dbs->acb = NULL;
 139     dbs->sector_num += dbs->iov.size / 512;
 140
 141     if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
 142         dma_complete(dbs, ret);
 143         return;
 144     }
 145     dma_bdrv_unmap(dbs);
 146
 147     while (dbs->sg_cur_index < dbs->sg->nsg) {
 148         cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte;
 149         cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte;
 150         mem = dma_memory_map(dbs->sg->as, cur_addr, &cur_len, dbs->dir);
 151         if (!mem)
 152             break;
 153         qemu_iovec_add(&dbs->iov, mem, cur_len);
 154         dbs->sg_cur_byte += cur_len;
 155         if (dbs->sg_cur_byte == dbs->sg->sg[dbs->sg_cur_index].len) {
 156             dbs->sg_cur_byte = 0;
 157             ++dbs->sg_cur_index;
 158         }
 159     }
 160
 161     if (dbs->iov.size == 0) {
 162         trace_dma_map_wait(dbs);
 163         cpu_register_map_client(dbs, continue_after_map_failure);
 164         return;
 165     }
 166
 167     if (dbs->iov.size & ~BDRV_SECTOR_MASK) {
 168         qemu_iovec_discard_back(&dbs->iov, dbs->iov.size & ~BDRV_SECTOR_MASK);
 169     }
 170
 171     dbs->acb = dbs->io_func(dbs->bs, dbs->sector_num, &dbs->iov,
 172                             dbs->iov.size / 512, dma_bdrv_cb, dbs);
 173     assert(dbs->acb);
 174 }
 175
 176 static void dma_aio_cancel(BlockDriverAIOCB *acb)
 177 {
 178     DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
 179
 180     trace_dma_aio_cancel(dbs);
 181
 182     if (dbs->acb) {
 183         bdrv_aio_cancel_async(dbs->acb);
 184     }
 185 }
 186
 187
 188 static const AIOCBInfo dma_aiocb_info = {
 189     .aiocb_size         = sizeof(DMAAIOCB),
 190     .cancel_async       = dma_aio_cancel,
 191 };
 192
 193 BlockDriverAIOCB *dma_bdrv_io(
 194     BlockDriverState *bs, QEMUSGList *sg, uint64_t sector_num,
 195     DMAIOFunc *io_func, BlockDriverCompletionFunc *cb,
 196     void *opaque, DMADirection dir)
 197 {
 198     DMAAIOCB *dbs = qemu_aio_get(&dma_aiocb_info, bs, cb, opaque);
 199
 200     trace_dma_bdrv_io(dbs, bs, sector_num, (dir == DMA_DIRECTION_TO_DEVICE));
 201
 202     dbs->acb = NULL;
 203     dbs->bs = bs;
 204     dbs->sg = sg;
 205     dbs->sector_num = sector_num;
 206     dbs->sg_cur_index = 0;
 207     dbs->sg_cur_byte = 0;
 208     dbs->dir = dir;
 209     dbs->io_func = io_func;
 210     dbs->bh = NULL;
 211     qemu_iovec_init(&dbs->iov, sg->nsg);
 212     dma_bdrv_cb(dbs, 0);
 213     return &dbs->common;
 214 }
 215
 216
 217 BlockDriverAIOCB *dma_bdrv_read(BlockDriverState *bs,
 218                                 QEMUSGList *sg, uint64_t sector,
 219                                 void (*cb)(void *opaque, int ret), void *opaque)
 220 {
 221     return dma_bdrv_io(bs, sg, sector, bdrv_aio_readv, cb, opaque,
 222                        DMA_DIRECTION_FROM_DEVICE);
 223 }
 224
 225 BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs,
 226                                  QEMUSGList *sg, uint64_t sector,
 227                                  void (*cb)(void *opaque, int ret), void *opaque)
 228 {
 229     return dma_bdrv_io(bs, sg, sector, bdrv_aio_writev, cb, opaque,
 230                        DMA_DIRECTION_TO_DEVICE);
 231 }
 232
 233
 234 static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg,
 235                            DMADirection dir)
 236 {
 237     uint64_t resid;
 238     int sg_cur_index;
 239
 240     resid = sg->size;
 241     sg_cur_index = 0;
 242     len = MIN(len, resid);
 243     while (len > 0) {
 244         ScatterGatherEntry entry = sg->sg[sg_cur_index++];
 245         int32_t xfer = MIN(len, entry.len);
 246         dma_memory_rw(sg->as, entry.base, ptr, xfer, dir);
 247         ptr += xfer;
 248         len -= xfer;
 249         resid -= xfer;
 250     }
 251
 252     return resid;
 253 }
 254
 255 uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg)
 256 {
 257     return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_FROM_DEVICE);
 258 }
 259
 260 uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg)
 261 {
 262     return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_TO_DEVICE);
 263 }
 264
 265 void dma_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie,
 266                     QEMUSGList *sg, enum BlockAcctType type)
 267 {
 268     block_acct_start(bdrv_get_stats(bs), cookie, sg->size, type);
 269 }