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
  15 /* #define DEBUG_IOMMU */
  16
  17 static void do_dma_memory_set(AddressSpace *as,
  18                               dma_addr_t addr, uint8_t c, dma_addr_t len)
  19 {
  20 #define FILLBUF_SIZE 512
  21     uint8_t fillbuf[FILLBUF_SIZE];
  22     int l;
  23
  24     memset(fillbuf, c, FILLBUF_SIZE);
  25     while (len > 0) {
  26         l = len < FILLBUF_SIZE ? len : FILLBUF_SIZE;
  27         address_space_rw(as, addr, fillbuf, l, true);
  28         len -= l;
  29         addr += l;
  30     }
  31 }
  32
  33 int dma_memory_set(DMAContext *dma, dma_addr_t addr, uint8_t c, dma_addr_t len)
  34 {
  35     dma_barrier(dma, DMA_DIRECTION_FROM_DEVICE);
  36
  37     if (dma_has_iommu(dma)) {
  38         return iommu_dma_memory_set(dma, addr, c, len);
  39     }
  40     do_dma_memory_set(dma->as, addr, c, len);
  41
  42     return 0;
  43 }
  44
  45 void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint, DMAContext *dma)
  46 {
  47     qsg->sg = g_malloc(alloc_hint * sizeof(ScatterGatherEntry));
  48     qsg->nsg = 0;
  49     qsg->nalloc = alloc_hint;
  50     qsg->size = 0;
  51     qsg->dma = dma;
  52 }
  53
  54 void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len)
  55 {
  56     if (qsg->nsg == qsg->nalloc) {
  57         qsg->nalloc = 2 * qsg->nalloc + 1;
  58         qsg->sg = g_realloc(qsg->sg, qsg->nalloc * sizeof(ScatterGatherEntry));
  59     }
  60     qsg->sg[qsg->nsg].base = base;
  61     qsg->sg[qsg->nsg].len = len;
  62     qsg->size += len;
  63     ++qsg->nsg;
  64 }
  65
  66 void qemu_sglist_destroy(QEMUSGList *qsg)
  67 {
  68     g_free(qsg->sg);
  69     memset(qsg, 0, sizeof(*qsg));
  70 }
  71
  72 typedef struct {
  73     BlockDriverAIOCB common;
  74     BlockDriverState *bs;
  75     BlockDriverAIOCB *acb;
  76     QEMUSGList *sg;
  77     uint64_t sector_num;
  78     DMADirection dir;
  79     bool in_cancel;
  80     int sg_cur_index;
  81     dma_addr_t sg_cur_byte;
  82     QEMUIOVector iov;
  83     QEMUBH *bh;
  84     DMAIOFunc *io_func;
  85 } DMAAIOCB;
  86
  87 static void dma_bdrv_cb(void *opaque, int ret);
  88
  89 static void reschedule_dma(void *opaque)
  90 {
  91     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
  92
  93     qemu_bh_delete(dbs->bh);
  94     dbs->bh = NULL;
  95     dma_bdrv_cb(dbs, 0);
  96 }
  97
  98 static void continue_after_map_failure(void *opaque)
  99 {
 100     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
 101
 102     dbs->bh = qemu_bh_new(reschedule_dma, dbs);
 103     qemu_bh_schedule(dbs->bh);
 104 }
 105
 106 static void dma_bdrv_unmap(DMAAIOCB *dbs)
 107 {
 108     int i;
 109
 110     for (i = 0; i < dbs->iov.niov; ++i) {
 111         dma_memory_unmap(dbs->sg->dma, dbs->iov.iov[i].iov_base,
 112                          dbs->iov.iov[i].iov_len, dbs->dir,
 113                          dbs->iov.iov[i].iov_len);
 114     }
 115     qemu_iovec_reset(&dbs->iov);
 116 }
 117
 118 static void dma_complete(DMAAIOCB *dbs, int ret)
 119 {
 120     trace_dma_complete(dbs, ret, dbs->common.cb);
 121
 122     dma_bdrv_unmap(dbs);
 123     if (dbs->common.cb) {
 124         dbs->common.cb(dbs->common.opaque, ret);
 125     }
 126     qemu_iovec_destroy(&dbs->iov);
 127     if (dbs->bh) {
 128         qemu_bh_delete(dbs->bh);
 129         dbs->bh = NULL;
 130     }
 131     if (!dbs->in_cancel) {
 132         /* Requests may complete while dma_aio_cancel is in progress.  In
 133          * this case, the AIOCB should not be released because it is still
 134          * referenced by dma_aio_cancel.  */
 135         qemu_aio_release(dbs);
 136     }
 137 }
 138
 139 static void dma_bdrv_cb(void *opaque, int ret)
 140 {
 141     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
 142     dma_addr_t cur_addr, cur_len;
 143     void *mem;
 144
 145     trace_dma_bdrv_cb(dbs, ret);
 146
 147     dbs->acb = NULL;
 148     dbs->sector_num += dbs->iov.size / 512;
 149     dma_bdrv_unmap(dbs);
 150
 151     if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
 152         dma_complete(dbs, ret);
 153         return;
 154     }
 155
 156     while (dbs->sg_cur_index < dbs->sg->nsg) {
 157         cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte;
 158         cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte;
 159         mem = dma_memory_map(dbs->sg->dma, cur_addr, &cur_len, dbs->dir);
 160         if (!mem)
 161             break;
 162         qemu_iovec_add(&dbs->iov, mem, cur_len);
 163         dbs->sg_cur_byte += cur_len;
 164         if (dbs->sg_cur_byte == dbs->sg->sg[dbs->sg_cur_index].len) {
 165             dbs->sg_cur_byte = 0;
 166             ++dbs->sg_cur_index;
 167         }
 168     }
 169
 170     if (dbs->iov.size == 0) {
 171         trace_dma_map_wait(dbs);
 172         cpu_register_map_client(dbs, continue_after_map_failure);
 173         return;
 174     }
 175
 176     dbs->acb = dbs->io_func(dbs->bs, dbs->sector_num, &dbs->iov,
 177                             dbs->iov.size / 512, dma_bdrv_cb, dbs);
 178     assert(dbs->acb);
 179 }
 180
 181 static void dma_aio_cancel(BlockDriverAIOCB *acb)
 182 {
 183     DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
 184
 185     trace_dma_aio_cancel(dbs);
 186
 187     if (dbs->acb) {
 188         BlockDriverAIOCB *acb = dbs->acb;
 189         dbs->acb = NULL;
 190         dbs->in_cancel = true;
 191         bdrv_aio_cancel(acb);
 192         dbs->in_cancel = false;
 193     }
 194     dbs->common.cb = NULL;
 195     dma_complete(dbs, 0);
 196 }
 197
 198 static const AIOCBInfo dma_aiocb_info = {
 199     .aiocb_size         = sizeof(DMAAIOCB),
 200     .cancel             = dma_aio_cancel,
 201 };
 202
 203 BlockDriverAIOCB *dma_bdrv_io(
 204     BlockDriverState *bs, QEMUSGList *sg, uint64_t sector_num,
 205     DMAIOFunc *io_func, BlockDriverCompletionFunc *cb,
 206     void *opaque, DMADirection dir)
 207 {
 208     DMAAIOCB *dbs = qemu_aio_get(&dma_aiocb_info, bs, cb, opaque);
 209
 210     trace_dma_bdrv_io(dbs, bs, sector_num, (dir == DMA_DIRECTION_TO_DEVICE));
 211
 212     dbs->acb = NULL;
 213     dbs->bs = bs;
 214     dbs->sg = sg;
 215     dbs->sector_num = sector_num;
 216     dbs->sg_cur_index = 0;
 217     dbs->sg_cur_byte = 0;
 218     dbs->dir = dir;
 219     dbs->io_func = io_func;
 220     dbs->bh = NULL;
 221     qemu_iovec_init(&dbs->iov, sg->nsg);
 222     dma_bdrv_cb(dbs, 0);
 223     return &dbs->common;
 224 }
 225
 226
 227 BlockDriverAIOCB *dma_bdrv_read(BlockDriverState *bs,
 228                                 QEMUSGList *sg, uint64_t sector,
 229                                 void (*cb)(void *opaque, int ret), void *opaque)
 230 {
 231     return dma_bdrv_io(bs, sg, sector, bdrv_aio_readv, cb, opaque,
 232                        DMA_DIRECTION_FROM_DEVICE);
 233 }
 234
 235 BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs,
 236                                  QEMUSGList *sg, uint64_t sector,
 237                                  void (*cb)(void *opaque, int ret), void *opaque)
 238 {
 239     return dma_bdrv_io(bs, sg, sector, bdrv_aio_writev, cb, opaque,
 240                        DMA_DIRECTION_TO_DEVICE);
 241 }
 242
 243
 244 static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg,
 245                            DMADirection dir)
 246 {
 247     uint64_t resid;
 248     int sg_cur_index;
 249
 250     resid = sg->size;
 251     sg_cur_index = 0;
 252     len = MIN(len, resid);
 253     while (len > 0) {
 254         ScatterGatherEntry entry = sg->sg[sg_cur_index++];
 255         int32_t xfer = MIN(len, entry.len);
 256         dma_memory_rw(sg->dma, entry.base, ptr, xfer, dir);
 257         ptr += xfer;
 258         len -= xfer;
 259         resid -= xfer;
 260     }
 261
 262     return resid;
 263 }
 264
 265 uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg)
 266 {
 267     return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_FROM_DEVICE);
 268 }
 269
 270 uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg)
 271 {
 272     return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_TO_DEVICE);
 273 }
 274
 275 void dma_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie,
 276                     QEMUSGList *sg, enum BlockAcctType type)
 277 {
 278     bdrv_acct_start(bs, cookie, sg->size, type);
 279 }
 280
 281 bool iommu_dma_memory_valid(DMAContext *dma, dma_addr_t addr, dma_addr_t len,
 282                             DMADirection dir)
 283 {
 284     hwaddr paddr, plen;
 285
 286 #ifdef DEBUG_IOMMU
 287     fprintf(stderr, "dma_memory_check context=%p addr=0x" DMA_ADDR_FMT
 288             " len=0x" DMA_ADDR_FMT " dir=%d\n", dma, addr, len, dir);
 289 #endif
 290
 291     while (len) {
 292         if (dma->translate(dma, addr, &paddr, &plen, dir) != 0) {
 293             return false;
 294         }
 295
 296         /* The translation might be valid for larger regions. */
 297         if (plen > len) {
 298             plen = len;
 299         }
 300
 301         len -= plen;
 302         addr += plen;
 303     }
 304
 305     return true;
 306 }
 307
 308 int iommu_dma_memory_rw(DMAContext *dma, dma_addr_t addr,
 309                         void *buf, dma_addr_t len, DMADirection dir)
 310 {
 311     hwaddr paddr, plen;
 312     int err;
 313
 314 #ifdef DEBUG_IOMMU
 315     fprintf(stderr, "dma_memory_rw context=%p addr=0x" DMA_ADDR_FMT " len=0x"
 316             DMA_ADDR_FMT " dir=%d\n", dma, addr, len, dir);
 317 #endif
 318
 319     while (len) {
 320         err = dma->translate(dma, addr, &paddr, &plen, dir);
 321         if (err) {
 322             /*
 323              * In case of failure on reads from the guest, we clean the
 324              * destination buffer so that a device that doesn't test
 325              * for errors will not expose qemu internal memory.
 326              */
 327             memset(buf, 0, len);
 328             return -1;
 329         }
 330
 331         /* The translation might be valid for larger regions. */
 332         if (plen > len) {
 333             plen = len;
 334         }
 335
 336         address_space_rw(dma->as, paddr, buf, plen, dir == DMA_DIRECTION_FROM_DEVICE);
 337
 338         len -= plen;
 339         addr += plen;
 340         buf += plen;
 341     }
 342
 343     return 0;
 344 }
 345
 346 int iommu_dma_memory_set(DMAContext *dma, dma_addr_t addr, uint8_t c,
 347                          dma_addr_t len)
 348 {
 349     hwaddr paddr, plen;
 350     int err;
 351
 352 #ifdef DEBUG_IOMMU
 353     fprintf(stderr, "dma_memory_set context=%p addr=0x" DMA_ADDR_FMT
 354             " len=0x" DMA_ADDR_FMT "\n", dma, addr, len);
 355 #endif
 356
 357     while (len) {
 358         err = dma->translate(dma, addr, &paddr, &plen,
 359                              DMA_DIRECTION_FROM_DEVICE);
 360         if (err) {
 361             return err;
 362         }
 363
 364         /* The translation might be valid for larger regions. */
 365         if (plen > len) {
 366             plen = len;
 367         }
 368
 369         do_dma_memory_set(dma->as, paddr, c, plen);
 370
 371         len -= plen;
 372         addr += plen;
 373     }
 374
 375     return 0;
 376 }
 377
 378 void dma_context_init(DMAContext *dma, AddressSpace *as, DMATranslateFunc translate,
 379                       DMAMapFunc map, DMAUnmapFunc unmap)
 380 {
 381 #ifdef DEBUG_IOMMU
 382     fprintf(stderr, "dma_context_init(%p, %p, %p, %p)\n",
 383             dma, translate, map, unmap);
 384 #endif
 385     dma->as = as;
 386     dma->translate = translate;
 387     dma->map = map;
 388     dma->unmap = unmap;
 389 }
 390
 391 void *iommu_dma_memory_map(DMAContext *dma, dma_addr_t addr, dma_addr_t *len,
 392                            DMADirection dir)
 393 {
 394     int err;
 395     hwaddr paddr, plen;
 396     void *buf;
 397
 398     if (dma->map) {
 399         return dma->map(dma, addr, len, dir);
 400     }
 401
 402     plen = *len;
 403     err = dma->translate(dma, addr, &paddr, &plen, dir);
 404     if (err) {
 405         return NULL;
 406     }
 407
 408     /*
 409      * If this is true, the virtual region is contiguous,
 410      * but the translated physical region isn't. We just
 411      * clamp *len, much like address_space_map() does.
 412      */
 413     if (plen < *len) {
 414         *len = plen;
 415     }
 416
 417     buf = address_space_map(dma->as, paddr, &plen, dir == DMA_DIRECTION_FROM_DEVICE);
 418     *len = plen;
 419
 420     return buf;
 421 }
 422
 423 void iommu_dma_memory_unmap(DMAContext *dma, void *buffer, dma_addr_t len,
 424                             DMADirection dir, dma_addr_t access_len)
 425 {
 426     if (dma->unmap) {
 427         dma->unmap(dma, buffer, len, dir, access_len);
 428         return;
 429     }
 430
 431     address_space_unmap(dma->as, buffer, len, dir == DMA_DIRECTION_FROM_DEVICE,
 432                         access_len);
 433
 434 }