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     bool in_cancel;
  77     int sg_cur_index;
  78     dma_addr_t sg_cur_byte;
  79     QEMUIOVector iov;
  80     QEMUBH *bh;
  81     DMAIOFunc *io_func;
  82 } DMAAIOCB;
  83
  84 static void dma_bdrv_cb(void *opaque, int ret);
  85
  86 static void reschedule_dma(void *opaque)
  87 {
  88     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
  89
  90     qemu_bh_delete(dbs->bh);
  91     dbs->bh = NULL;
  92     dma_bdrv_cb(dbs, 0);
  93 }
  94
  95 static void continue_after_map_failure(void *opaque)
  96 {
  97     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
  98
  99     dbs->bh = qemu_bh_new(reschedule_dma, dbs);
 100     qemu_bh_schedule(dbs->bh);
 101 }
 102
 103 static void dma_bdrv_unmap(DMAAIOCB *dbs)
 104 {
 105     int i;
 106
 107     for (i = 0; i < dbs->iov.niov; ++i) {
 108         dma_memory_unmap(dbs->sg->as, dbs->iov.iov[i].iov_base,
 109                          dbs->iov.iov[i].iov_len, dbs->dir,
 110                          dbs->iov.iov[i].iov_len);
 111     }
 112     qemu_iovec_reset(&dbs->iov);
 113 }
 114
 115 static void dma_complete(DMAAIOCB *dbs, int ret)
 116 {
 117     trace_dma_complete(dbs, ret, dbs->common.cb);
 118
 119     dma_bdrv_unmap(dbs);
 120     if (dbs->common.cb) {
 121         dbs->common.cb(dbs->common.opaque, ret);
 122     }
 123     qemu_iovec_destroy(&dbs->iov);
 124     if (dbs->bh) {
 125         qemu_bh_delete(dbs->bh);
 126         dbs->bh = NULL;
 127     }
 128     if (!dbs->in_cancel) {
 129         /* Requests may complete while dma_aio_cancel is in progress.  In
 130          * this case, the AIOCB should not be released because it is still
 131          * referenced by dma_aio_cancel.  */
 132         qemu_aio_release(dbs);
 133     }
 134 }
 135
 136 static void dma_bdrv_cb(void *opaque, int ret)
 137 {
 138     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
 139     dma_addr_t cur_addr, cur_len;
 140     void *mem;
 141
 142     trace_dma_bdrv_cb(dbs, ret);
 143
 144     dbs->acb = NULL;
 145     dbs->sector_num += dbs->iov.size / 512;
 146
 147     if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
 148         dma_complete(dbs, ret);
 149         return;
 150     }
 151     dma_bdrv_unmap(dbs);
 152
 153     while (dbs->sg_cur_index < dbs->sg->nsg) {
 154         cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte;
 155         cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte;
 156         mem = dma_memory_map(dbs->sg->as, cur_addr, &cur_len, dbs->dir);
 157         if (!mem)
 158             break;
 159         qemu_iovec_add(&dbs->iov, mem, cur_len);
 160         dbs->sg_cur_byte += cur_len;
 161         if (dbs->sg_cur_byte == dbs->sg->sg[dbs->sg_cur_index].len) {
 162             dbs->sg_cur_byte = 0;
 163             ++dbs->sg_cur_index;
 164         }
 165     }
 166
 167     if (dbs->iov.size == 0) {
 168         trace_dma_map_wait(dbs);
 169         cpu_register_map_client(dbs, continue_after_map_failure);
 170         return;
 171     }
 172
 173     if (dbs->iov.size & ~BDRV_SECTOR_MASK) {
 174         qemu_iovec_discard_back(&dbs->iov, dbs->iov.size & ~BDRV_SECTOR_MASK);
 175     }
 176
 177     dbs->acb = dbs->io_func(dbs->bs, dbs->sector_num, &dbs->iov,
 178                             dbs->iov.size / 512, dma_bdrv_cb, dbs);
 179     assert(dbs->acb);
 180 }
 181
 182 static void dma_aio_cancel(BlockDriverAIOCB *acb)
 183 {
 184     DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
 185
 186     trace_dma_aio_cancel(dbs);
 187
 188     if (dbs->acb) {
 189         BlockDriverAIOCB *acb = dbs->acb;
 190         dbs->acb = NULL;
 191         dbs->in_cancel = true;
 192         bdrv_aio_cancel(acb);
 193         dbs->in_cancel = false;
 194     }
 195     dbs->common.cb = NULL;
 196     dma_complete(dbs, 0);
 197 }
 198
 199 static const AIOCBInfo dma_aiocb_info = {
 200     .aiocb_size         = sizeof(DMAAIOCB),
 201     .cancel             = dma_aio_cancel,
 202 };
 203
 204 BlockDriverAIOCB *dma_bdrv_io(
 205     BlockDriverState *bs, QEMUSGList *sg, uint64_t sector_num,
 206     DMAIOFunc *io_func, BlockDriverCompletionFunc *cb,
 207     void *opaque, DMADirection dir)
 208 {
 209     DMAAIOCB *dbs = qemu_aio_get(&dma_aiocb_info, bs, cb, opaque);
 210
 211     trace_dma_bdrv_io(dbs, bs, sector_num, (dir == DMA_DIRECTION_TO_DEVICE));
 212
 213     dbs->acb = NULL;
 214     dbs->bs = bs;
 215     dbs->sg = sg;
 216     dbs->sector_num = sector_num;
 217     dbs->sg_cur_index = 0;
 218     dbs->sg_cur_byte = 0;
 219     dbs->dir = dir;
 220     dbs->in_cancel = false;
 221     dbs->io_func = io_func;
 222     dbs->bh = NULL;
 223     qemu_iovec_init(&dbs->iov, sg->nsg);
 224     dma_bdrv_cb(dbs, 0);
 225     return &dbs->common;
 226 }
 227
 228
 229 BlockDriverAIOCB *dma_bdrv_read(BlockDriverState *bs,
 230                                 QEMUSGList *sg, uint64_t sector,
 231                                 void (*cb)(void *opaque, int ret), void *opaque)
 232 {
 233     return dma_bdrv_io(bs, sg, sector, bdrv_aio_readv, cb, opaque,
 234                        DMA_DIRECTION_FROM_DEVICE);
 235 }
 236
 237 BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs,
 238                                  QEMUSGList *sg, uint64_t sector,
 239                                  void (*cb)(void *opaque, int ret), void *opaque)
 240 {
 241     return dma_bdrv_io(bs, sg, sector, bdrv_aio_writev, cb, opaque,
 242                        DMA_DIRECTION_TO_DEVICE);
 243 }
 244
 245
 246 static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg,
 247                            DMADirection dir)
 248 {
 249     uint64_t resid;
 250     int sg_cur_index;
 251
 252     resid = sg->size;
 253     sg_cur_index = 0;
 254     len = MIN(len, resid);
 255     while (len > 0) {
 256         ScatterGatherEntry entry = sg->sg[sg_cur_index++];
 257         int32_t xfer = MIN(len, entry.len);
 258         dma_memory_rw(sg->as, entry.base, ptr, xfer, dir);
 259         ptr += xfer;
 260         len -= xfer;
 261         resid -= xfer;
 262     }
 263
 264     return resid;
 265 }
 266
 267 uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg)
 268 {
 269     return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_FROM_DEVICE);
 270 }
 271
 272 uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg)
 273 {
 274     return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_TO_DEVICE);
 275 }
 276
 277 void dma_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie,
 278                     QEMUSGList *sg, enum BlockAcctType type)
 279 {
 280     bdrv_acct_start(bs, cookie, sg->size, type);
 281 }