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 "qemu/osdep.h"
  11 #include "sysemu/block-backend.h"
  12 #include "sysemu/dma.h"
  13 #include "trace-root.h"
  14 #include "qemu/thread.h"
  15 #include "qemu/main-loop.h"
  16
  17 /* #define DEBUG_IOMMU */
  18
  19 int dma_memory_set(AddressSpace *as, dma_addr_t addr, uint8_t c, dma_addr_t len)
  20 {
  21     dma_barrier(as, DMA_DIRECTION_FROM_DEVICE);
  22
  23 #define FILLBUF_SIZE 512
  24     uint8_t fillbuf[FILLBUF_SIZE];
  25     int l;
  26     bool error = false;
  27
  28     memset(fillbuf, c, FILLBUF_SIZE);
  29     while (len > 0) {
  30         l = len < FILLBUF_SIZE ? len : FILLBUF_SIZE;
  31         error |= address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED,
  32                                   fillbuf, l, true);
  33         len -= l;
  34         addr += l;
  35     }
  36
  37     return error;
  38 }
  39
  40 void qemu_sglist_init(QEMUSGList *qsg, DeviceState *dev, int alloc_hint,
  41                       AddressSpace *as)
  42 {
  43     qsg->sg = g_malloc(alloc_hint * sizeof(ScatterGatherEntry));
  44     qsg->nsg = 0;
  45     qsg->nalloc = alloc_hint;
  46     qsg->size = 0;
  47     qsg->as = as;
  48     qsg->dev = dev;
  49     object_ref(OBJECT(dev));
  50 }
  51
  52 void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len)
  53 {
  54     if (qsg->nsg == qsg->nalloc) {
  55         qsg->nalloc = 2 * qsg->nalloc + 1;
  56         qsg->sg = g_realloc(qsg->sg, qsg->nalloc * sizeof(ScatterGatherEntry));
  57     }
  58     qsg->sg[qsg->nsg].base = base;
  59     qsg->sg[qsg->nsg].len = len;
  60     qsg->size += len;
  61     ++qsg->nsg;
  62 }
  63
  64 void qemu_sglist_destroy(QEMUSGList *qsg)
  65 {
  66     object_unref(OBJECT(qsg->dev));
  67     g_free(qsg->sg);
  68     memset(qsg, 0, sizeof(*qsg));
  69 }
  70
  71 typedef struct {
  72     BlockAIOCB common;
  73     AioContext *ctx;
  74     BlockAIOCB *acb;
  75     QEMUSGList *sg;
  76     uint32_t align;
  77     uint64_t offset;
  78     DMADirection dir;
  79     int sg_cur_index;
  80     dma_addr_t sg_cur_byte;
  81     QEMUIOVector iov;
  82     QEMUBH *bh;
  83     DMAIOFunc *io_func;
  84     void *io_func_opaque;
  85 } DMAAIOCB;
  86
  87 static void dma_blk_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_blk_cb(dbs, 0);
  96 }
  97
  98 static void dma_blk_unmap(DMAAIOCB *dbs)
  99 {
 100     int i;
 101
 102     for (i = 0; i < dbs->iov.niov; ++i) {
 103         dma_memory_unmap(dbs->sg->as, dbs->iov.iov[i].iov_base,
 104                          dbs->iov.iov[i].iov_len, dbs->dir,
 105                          dbs->iov.iov[i].iov_len);
 106     }
 107     qemu_iovec_reset(&dbs->iov);
 108 }
 109
 110 static void dma_complete(DMAAIOCB *dbs, int ret)
 111 {
 112     trace_dma_complete(dbs, ret, dbs->common.cb);
 113
 114     dma_blk_unmap(dbs);
 115     if (dbs->common.cb) {
 116         dbs->common.cb(dbs->common.opaque, ret);
 117     }
 118     qemu_iovec_destroy(&dbs->iov);
 119     if (dbs->bh) {
 120         qemu_bh_delete(dbs->bh);
 121         dbs->bh = NULL;
 122     }
 123     qemu_aio_unref(dbs);
 124 }
 125
 126 static void dma_blk_cb(void *opaque, int ret)
 127 {
 128     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
 129     dma_addr_t cur_addr, cur_len;
 130     void *mem;
 131
 132     trace_dma_blk_cb(dbs, ret);
 133
 134     dbs->acb = NULL;
 135     dbs->offset += dbs->iov.size;
 136
 137     if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
 138         dma_complete(dbs, ret);
 139         return;
 140     }
 141     dma_blk_unmap(dbs);
 142
 143     while (dbs->sg_cur_index < dbs->sg->nsg) {
 144         cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte;
 145         cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte;
 146         mem = dma_memory_map(dbs->sg->as, cur_addr, &cur_len, dbs->dir);
 147         if (!mem)
 148             break;
 149         qemu_iovec_add(&dbs->iov, mem, cur_len);
 150         dbs->sg_cur_byte += cur_len;
 151         if (dbs->sg_cur_byte == dbs->sg->sg[dbs->sg_cur_index].len) {
 152             dbs->sg_cur_byte = 0;
 153             ++dbs->sg_cur_index;
 154         }
 155     }
 156
 157     if (dbs->iov.size == 0) {
 158         trace_dma_map_wait(dbs);
 159         dbs->bh = aio_bh_new(dbs->ctx, reschedule_dma, dbs);
 160         cpu_register_map_client(dbs->bh);
 161         return;
 162     }
 163
 164     if (!QEMU_IS_ALIGNED(dbs->iov.size, dbs->align)) {
 165         qemu_iovec_discard_back(&dbs->iov,
 166                                 QEMU_ALIGN_DOWN(dbs->iov.size, dbs->align));
 167     }
 168
 169     aio_context_acquire(dbs->ctx);
 170     dbs->acb = dbs->io_func(dbs->offset, &dbs->iov,
 171                             dma_blk_cb, dbs, dbs->io_func_opaque);
 172     aio_context_release(dbs->ctx);
 173     assert(dbs->acb);
 174 }
 175
 176 static void dma_aio_cancel(BlockAIOCB *acb)
 177 {
 178     DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
 179
 180     trace_dma_aio_cancel(dbs);
 181
 182     if (dbs->acb) {
 183         blk_aio_cancel_async(dbs->acb);
 184     }
 185     if (dbs->bh) {
 186         cpu_unregister_map_client(dbs->bh);
 187         qemu_bh_delete(dbs->bh);
 188         dbs->bh = NULL;
 189     }
 190 }
 191
 192 static AioContext *dma_get_aio_context(BlockAIOCB *acb)
 193 {
 194     DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
 195
 196     return dbs->ctx;
 197 }
 198
 199 static const AIOCBInfo dma_aiocb_info = {
 200     .aiocb_size         = sizeof(DMAAIOCB),
 201     .cancel_async       = dma_aio_cancel,
 202     .get_aio_context    = dma_get_aio_context,
 203 };
 204
 205 BlockAIOCB *dma_blk_io(AioContext *ctx,
 206     QEMUSGList *sg, uint64_t offset, uint32_t align,
 207     DMAIOFunc *io_func, void *io_func_opaque,
 208     BlockCompletionFunc *cb,
 209     void *opaque, DMADirection dir)
 210 {
 211     DMAAIOCB *dbs = qemu_aio_get(&dma_aiocb_info, NULL, cb, opaque);
 212
 213     trace_dma_blk_io(dbs, io_func_opaque, offset, (dir == DMA_DIRECTION_TO_DEVICE));
 214
 215     dbs->acb = NULL;
 216     dbs->sg = sg;
 217     dbs->ctx = ctx;
 218     dbs->offset = offset;
 219     dbs->align = align;
 220     dbs->sg_cur_index = 0;
 221     dbs->sg_cur_byte = 0;
 222     dbs->dir = dir;
 223     dbs->io_func = io_func;
 224     dbs->io_func_opaque = io_func_opaque;
 225     dbs->bh = NULL;
 226     qemu_iovec_init(&dbs->iov, sg->nsg);
 227     dma_blk_cb(dbs, 0);
 228     return &dbs->common;
 229 }
 230
 231
 232 static
 233 BlockAIOCB *dma_blk_read_io_func(int64_t offset, QEMUIOVector *iov,
 234                                  BlockCompletionFunc *cb, void *cb_opaque,
 235                                  void *opaque)
 236 {
 237     BlockBackend *blk = opaque;
 238     return blk_aio_preadv(blk, offset, iov, 0, cb, cb_opaque);
 239 }
 240
 241 BlockAIOCB *dma_blk_read(BlockBackend *blk,
 242                          QEMUSGList *sg, uint64_t offset, uint32_t align,
 243                          void (*cb)(void *opaque, int ret), void *opaque)
 244 {
 245     return dma_blk_io(blk_get_aio_context(blk), sg, offset, align,
 246                       dma_blk_read_io_func, blk, cb, opaque,
 247                       DMA_DIRECTION_FROM_DEVICE);
 248 }
 249
 250 static
 251 BlockAIOCB *dma_blk_write_io_func(int64_t offset, QEMUIOVector *iov,
 252                                   BlockCompletionFunc *cb, void *cb_opaque,
 253                                   void *opaque)
 254 {
 255     BlockBackend *blk = opaque;
 256     return blk_aio_pwritev(blk, offset, iov, 0, cb, cb_opaque);
 257 }
 258
 259 BlockAIOCB *dma_blk_write(BlockBackend *blk,
 260                           QEMUSGList *sg, uint64_t offset, uint32_t align,
 261                           void (*cb)(void *opaque, int ret), void *opaque)
 262 {
 263     return dma_blk_io(blk_get_aio_context(blk), sg, offset, align,
 264                       dma_blk_write_io_func, blk, cb, opaque,
 265                       DMA_DIRECTION_TO_DEVICE);
 266 }
 267
 268
 269 static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg,
 270                            DMADirection dir)
 271 {
 272     uint64_t resid;
 273     int sg_cur_index;
 274
 275     resid = sg->size;
 276     sg_cur_index = 0;
 277     len = MIN(len, resid);
 278     while (len > 0) {
 279         ScatterGatherEntry entry = sg->sg[sg_cur_index++];
 280         int32_t xfer = MIN(len, entry.len);
 281         dma_memory_rw(sg->as, entry.base, ptr, xfer, dir);
 282         ptr += xfer;
 283         len -= xfer;
 284         resid -= xfer;
 285     }
 286
 287     return resid;
 288 }
 289
 290 uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg)
 291 {
 292     return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_FROM_DEVICE);
 293 }
 294
 295 uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg)
 296 {
 297     return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_TO_DEVICE);
 298 }
 299
 300 void dma_acct_start(BlockBackend *blk, BlockAcctCookie *cookie,
 301                     QEMUSGList *sg, enum BlockAcctType type)
 302 {
 303     block_acct_start(blk_get_stats(blk), cookie, sg->size, type);
 304 }