aboutsummaryrefslogtreecommitdiff
path: root/dma-helpers.c
blob: 272632f3671988e479d0c3473efbb8c12b1bb075 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
/*
 * DMA helper functions
 *
 * Copyright (c) 2009 Red Hat
 *
 * This work is licensed under the terms of the GNU General Public License
 * (GNU GPL), version 2 or later.
 */

#include "sysemu/dma.h"
#include "trace.h"
#include "qemu/range.h"
#include "qemu/thread.h"

/* #define DEBUG_IOMMU */

static void do_dma_memory_set(AddressSpace *as,
                              dma_addr_t addr, uint8_t c, dma_addr_t len)
{
#define FILLBUF_SIZE 512
    uint8_t fillbuf[FILLBUF_SIZE];
    int l;

    memset(fillbuf, c, FILLBUF_SIZE);
    while (len > 0) {
        l = len < FILLBUF_SIZE ? len : FILLBUF_SIZE;
        address_space_rw(as, addr, fillbuf, l, true);
        len -= l;
        addr += l;
    }
}

int dma_memory_set(DMAContext *dma, dma_addr_t addr, uint8_t c, dma_addr_t len)
{
    dma_barrier(dma, DMA_DIRECTION_FROM_DEVICE);

    if (dma_has_iommu(dma)) {
        return iommu_dma_memory_set(dma, addr, c, len);
    }
    do_dma_memory_set(dma->as, addr, c, len);

    return 0;
}

void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint, DMAContext *dma)
{
    qsg->sg = g_malloc(alloc_hint * sizeof(ScatterGatherEntry));
    qsg->nsg = 0;
    qsg->nalloc = alloc_hint;
    qsg->size = 0;
    qsg->dma = dma;
}

void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len)
{
    if (qsg->nsg == qsg->nalloc) {
        qsg->nalloc = 2 * qsg->nalloc + 1;
        qsg->sg = g_realloc(qsg->sg, qsg->nalloc * sizeof(ScatterGatherEntry));
    }
    qsg->sg[qsg->nsg].base = base;
    qsg->sg[qsg->nsg].len = len;
    qsg->size += len;
    ++qsg->nsg;
}

void qemu_sglist_destroy(QEMUSGList *qsg)
{
    g_free(qsg->sg);
    memset(qsg, 0, sizeof(*qsg));
}

typedef struct {
    BlockDriverAIOCB common;
    BlockDriverState *bs;
    BlockDriverAIOCB *acb;
    QEMUSGList *sg;
    uint64_t sector_num;
    DMADirection dir;
    bool in_cancel;
    int sg_cur_index;
    dma_addr_t sg_cur_byte;
    QEMUIOVector iov;
    QEMUBH *bh;
    DMAIOFunc *io_func;
} DMAAIOCB;

static void dma_bdrv_cb(void *opaque, int ret);

static void reschedule_dma(void *opaque)
{
    DMAAIOCB *dbs = (DMAAIOCB *)opaque;

    qemu_bh_delete(dbs->bh);
    dbs->bh = NULL;
    dma_bdrv_cb(dbs, 0);
}

static void continue_after_map_failure(void *opaque)
{
    DMAAIOCB *dbs = (DMAAIOCB *)opaque;

    dbs->bh = qemu_bh_new(reschedule_dma, dbs);
    qemu_bh_schedule(dbs->bh);
}

static void dma_bdrv_unmap(DMAAIOCB *dbs)
{
    int i;

    for (i = 0; i < dbs->iov.niov; ++i) {
        dma_memory_unmap(dbs->sg->dma, dbs->iov.iov[i].iov_base,
                         dbs->iov.iov[i].iov_len, dbs->dir,
                         dbs->iov.iov[i].iov_len);
    }
    qemu_iovec_reset(&dbs->iov);
}

static void dma_complete(DMAAIOCB *dbs, int ret)
{
    trace_dma_complete(dbs, ret, dbs->common.cb);

    dma_bdrv_unmap(dbs);
    if (dbs->common.cb) {
        dbs->common.cb(dbs->common.opaque, ret);
    }
    qemu_iovec_destroy(&dbs->iov);
    if (dbs->bh) {
        qemu_bh_delete(dbs->bh);
        dbs->bh = NULL;
    }
    if (!dbs->in_cancel) {
        /* Requests may complete while dma_aio_cancel is in progress.  In
         * this case, the AIOCB should not be released because it is still
         * referenced by dma_aio_cancel.  */
        qemu_aio_release(dbs);
    }
}

static void dma_bdrv_cb(void *opaque, int ret)
{
    DMAAIOCB *dbs = (DMAAIOCB *)opaque;
    dma_addr_t cur_addr, cur_len;
    void *mem;

    trace_dma_bdrv_cb(dbs, ret);

    dbs->acb = NULL;
    dbs->sector_num += dbs->iov.size / 512;
    dma_bdrv_unmap(dbs);

    if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
        dma_complete(dbs, ret);
        return;
    }

    while (dbs->sg_cur_index < dbs->sg->nsg) {
        cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte;
        cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte;
        mem = dma_memory_map(dbs->sg->dma, cur_addr, &cur_len, dbs->dir);
        if (!mem)
            break;
        qemu_iovec_add(&dbs->iov, mem, cur_len);
        dbs->sg_cur_byte += cur_len;
        if (dbs->sg_cur_byte == dbs->sg->sg[dbs->sg_cur_index].len) {
            dbs->sg_cur_byte = 0;
            ++dbs->sg_cur_index;
        }
    }

    if (dbs->iov.size == 0) {
        trace_dma_map_wait(dbs);
        cpu_register_map_client(dbs, continue_after_map_failure);
        return;
    }

    dbs->acb = dbs->io_func(dbs->bs, dbs->sector_num, &dbs->iov,
                            dbs->iov.size / 512, dma_bdrv_cb, dbs);
    assert(dbs->acb);
}

static void dma_aio_cancel(BlockDriverAIOCB *acb)
{
    DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);

    trace_dma_aio_cancel(dbs);

    if (dbs->acb) {
        BlockDriverAIOCB *acb = dbs->acb;
        dbs->acb = NULL;
        dbs->in_cancel = true;
        bdrv_aio_cancel(acb);
        dbs->in_cancel = false;
    }
    dbs->common.cb = NULL;
    dma_complete(dbs, 0);
}

static const AIOCBInfo dma_aiocb_info = {
    .aiocb_size         = sizeof(DMAAIOCB),
    .cancel             = dma_aio_cancel,
};

BlockDriverAIOCB *dma_bdrv_io(
    BlockDriverState *bs, QEMUSGList *sg, uint64_t sector_num,
    DMAIOFunc *io_func, BlockDriverCompletionFunc *cb,
    void *opaque, DMADirection dir)
{
    DMAAIOCB *dbs = qemu_aio_get(&dma_aiocb_info, bs, cb, opaque);

    trace_dma_bdrv_io(dbs, bs, sector_num, (dir == DMA_DIRECTION_TO_DEVICE));

    dbs->acb = NULL;
    dbs->bs = bs;
    dbs->sg = sg;
    dbs->sector_num = sector_num;
    dbs->sg_cur_index = 0;
    dbs->sg_cur_byte = 0;
    dbs->dir = dir;
    dbs->io_func = io_func;
    dbs->bh = NULL;
    qemu_iovec_init(&dbs->iov, sg->nsg);
    dma_bdrv_cb(dbs, 0);
    return &dbs->common;
}


BlockDriverAIOCB *dma_bdrv_read(BlockDriverState *bs,
                                QEMUSGList *sg, uint64_t sector,
                                void (*cb)(void *opaque, int ret), void *opaque)
{
    return dma_bdrv_io(bs, sg, sector, bdrv_aio_readv, cb, opaque,
                       DMA_DIRECTION_FROM_DEVICE);
}

BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs,
                                 QEMUSGList *sg, uint64_t sector,
                                 void (*cb)(void *opaque, int ret), void *opaque)
{
    return dma_bdrv_io(bs, sg, sector, bdrv_aio_writev, cb, opaque,
                       DMA_DIRECTION_TO_DEVICE);
}


static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg,
                           DMADirection dir)
{
    uint64_t resid;
    int sg_cur_index;

    resid = sg->size;
    sg_cur_index = 0;
    len = MIN(len, resid);
    while (len > 0) {
        ScatterGatherEntry entry = sg->sg[sg_cur_index++];
        int32_t xfer = MIN(len, entry.len);
        dma_memory_rw(sg->dma, entry.base, ptr, xfer, dir);
        ptr += xfer;
        len -= xfer;
        resid -= xfer;
    }

    return resid;
}

uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg)
{
    return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_FROM_DEVICE);
}

uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg)
{
    return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_TO_DEVICE);
}

void dma_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie,
                    QEMUSGList *sg, enum BlockAcctType type)
{
    bdrv_acct_start(bs, cookie, sg->size, type);
}

bool iommu_dma_memory_valid(DMAContext *dma, dma_addr_t addr, dma_addr_t len,
                            DMADirection dir)
{
    hwaddr paddr, plen;

#ifdef DEBUG_IOMMU
    fprintf(stderr, "dma_memory_check context=%p addr=0x" DMA_ADDR_FMT
            " len=0x" DMA_ADDR_FMT " dir=%d\n", dma, addr, len, dir);
#endif

    while (len) {
        if (dma->translate(dma, addr, &paddr, &plen, dir) != 0) {
            return false;
        }

        /* The translation might be valid for larger regions. */
        if (plen > len) {
            plen = len;
        }

        len -= plen;
        addr += plen;
    }

    return true;
}

int iommu_dma_memory_rw(DMAContext *dma, dma_addr_t addr,
                        void *buf, dma_addr_t len, DMADirection dir)
{
    hwaddr paddr, plen;
    int err;

#ifdef DEBUG_IOMMU
    fprintf(stderr, "dma_memory_rw context=%p addr=0x" DMA_ADDR_FMT " len=0x"
            DMA_ADDR_FMT " dir=%d\n", dma, addr, len, dir);
#endif

    while (len) {
        err = dma->translate(dma, addr, &paddr, &plen, dir);
        if (err) {
	    /*
             * In case of failure on reads from the guest, we clean the
             * destination buffer so that a device that doesn't test
             * for errors will not expose qemu internal memory.
	     */
	    memset(buf, 0, len);
            return -1;
        }

        /* The translation might be valid for larger regions. */
        if (plen > len) {
            plen = len;
        }

        address_space_rw(dma->as, paddr, buf, plen, dir == DMA_DIRECTION_FROM_DEVICE);

        len -= plen;
        addr += plen;
        buf += plen;
    }

    return 0;
}

int iommu_dma_memory_set(DMAContext *dma, dma_addr_t addr, uint8_t c,
                         dma_addr_t len)
{
    hwaddr paddr, plen;
    int err;

#ifdef DEBUG_IOMMU
    fprintf(stderr, "dma_memory_set context=%p addr=0x" DMA_ADDR_FMT
            " len=0x" DMA_ADDR_FMT "\n", dma, addr, len);
#endif

    while (len) {
        err = dma->translate(dma, addr, &paddr, &plen,
                             DMA_DIRECTION_FROM_DEVICE);
        if (err) {
            return err;
        }

        /* The translation might be valid for larger regions. */
        if (plen > len) {
            plen = len;
        }

        do_dma_memory_set(dma->as, paddr, c, plen);

        len -= plen;
        addr += plen;
    }

    return 0;
}

void dma_context_init(DMAContext *dma, AddressSpace *as, DMATranslateFunc translate,
                      DMAMapFunc map, DMAUnmapFunc unmap)
{
#ifdef DEBUG_IOMMU
    fprintf(stderr, "dma_context_init(%p, %p, %p, %p)\n",
            dma, translate, map, unmap);
#endif
    dma->as = as;
    dma->translate = translate;
    dma->map = map;
    dma->unmap = unmap;
}

void *iommu_dma_memory_map(DMAContext *dma, dma_addr_t addr, dma_addr_t *len,
                           DMADirection dir)
{
    int err;
    hwaddr paddr, plen;
    void *buf;

    if (dma->map) {
        return dma->map(dma, addr, len, dir);
    }

    plen = *len;
    err = dma->translate(dma, addr, &paddr, &plen, dir);
    if (err) {
        return NULL;
    }

    /*
     * If this is true, the virtual region is contiguous,
     * but the translated physical region isn't. We just
     * clamp *len, much like address_space_map() does.
     */
    if (plen < *len) {
        *len = plen;
    }

    buf = address_space_map(dma->as, paddr, &plen, dir == DMA_DIRECTION_FROM_DEVICE);
    *len = plen;

    return buf;
}

void iommu_dma_memory_unmap(DMAContext *dma, void *buffer, dma_addr_t len,
                            DMADirection dir, dma_addr_t access_len)
{
    if (dma->unmap) {
        dma->unmap(dma, buffer, len, dir, access_len);
        return;
    }

    address_space_unmap(dma->as, buffer, len, dir == DMA_DIRECTION_FROM_DEVICE,
                        access_len);

}