Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging
[qemu.git] / 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 assert(!dbs->acb && dbs->bh);
94 qemu_bh_delete(dbs->bh);
95 dbs->bh = NULL;
96 dma_blk_cb(dbs, 0);
97 }
98
99 static void dma_blk_unmap(DMAAIOCB *dbs)
100 {
101 int i;
102
103 for (i = 0; i < dbs->iov.niov; ++i) {
104 dma_memory_unmap(dbs->sg->as, dbs->iov.iov[i].iov_base,
105 dbs->iov.iov[i].iov_len, dbs->dir,
106 dbs->iov.iov[i].iov_len);
107 }
108 qemu_iovec_reset(&dbs->iov);
109 }
110
111 static void dma_complete(DMAAIOCB *dbs, int ret)
112 {
113 trace_dma_complete(dbs, ret, dbs->common.cb);
114
115 assert(!dbs->acb && !dbs->bh);
116 dma_blk_unmap(dbs);
117 if (dbs->common.cb) {
118 dbs->common.cb(dbs->common.opaque, ret);
119 }
120 qemu_iovec_destroy(&dbs->iov);
121 qemu_aio_unref(dbs);
122 }
123
124 static void dma_blk_cb(void *opaque, int ret)
125 {
126 DMAAIOCB *dbs = (DMAAIOCB *)opaque;
127 dma_addr_t cur_addr, cur_len;
128 void *mem;
129
130 trace_dma_blk_cb(dbs, ret);
131
132 dbs->acb = NULL;
133 dbs->offset += dbs->iov.size;
134
135 if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
136 dma_complete(dbs, ret);
137 return;
138 }
139 dma_blk_unmap(dbs);
140
141 while (dbs->sg_cur_index < dbs->sg->nsg) {
142 cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte;
143 cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte;
144 mem = dma_memory_map(dbs->sg->as, cur_addr, &cur_len, dbs->dir);
145 if (!mem)
146 break;
147 qemu_iovec_add(&dbs->iov, mem, cur_len);
148 dbs->sg_cur_byte += cur_len;
149 if (dbs->sg_cur_byte == dbs->sg->sg[dbs->sg_cur_index].len) {
150 dbs->sg_cur_byte = 0;
151 ++dbs->sg_cur_index;
152 }
153 }
154
155 if (dbs->iov.size == 0) {
156 trace_dma_map_wait(dbs);
157 dbs->bh = aio_bh_new(dbs->ctx, reschedule_dma, dbs);
158 cpu_register_map_client(dbs->bh);
159 return;
160 }
161
162 if (!QEMU_IS_ALIGNED(dbs->iov.size, dbs->align)) {
163 qemu_iovec_discard_back(&dbs->iov,
164 QEMU_ALIGN_DOWN(dbs->iov.size, dbs->align));
165 }
166
167 aio_context_acquire(dbs->ctx);
168 dbs->acb = dbs->io_func(dbs->offset, &dbs->iov,
169 dma_blk_cb, dbs, dbs->io_func_opaque);
170 aio_context_release(dbs->ctx);
171 assert(dbs->acb);
172 }
173
174 static void dma_aio_cancel(BlockAIOCB *acb)
175 {
176 DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
177
178 trace_dma_aio_cancel(dbs);
179
180 assert(!(dbs->acb && dbs->bh));
181 if (dbs->acb) {
182 /* This will invoke dma_blk_cb. */
183 blk_aio_cancel_async(dbs->acb);
184 return;
185 }
186
187 if (dbs->bh) {
188 cpu_unregister_map_client(dbs->bh);
189 qemu_bh_delete(dbs->bh);
190 dbs->bh = NULL;
191 }
192 if (dbs->common.cb) {
193 dbs->common.cb(dbs->common.opaque, -ECANCELED);
194 }
195 }
196
197 static AioContext *dma_get_aio_context(BlockAIOCB *acb)
198 {
199 DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
200
201 return dbs->ctx;
202 }
203
204 static const AIOCBInfo dma_aiocb_info = {
205 .aiocb_size = sizeof(DMAAIOCB),
206 .cancel_async = dma_aio_cancel,
207 .get_aio_context = dma_get_aio_context,
208 };
209
210 BlockAIOCB *dma_blk_io(AioContext *ctx,
211 QEMUSGList *sg, uint64_t offset, uint32_t align,
212 DMAIOFunc *io_func, void *io_func_opaque,
213 BlockCompletionFunc *cb,
214 void *opaque, DMADirection dir)
215 {
216 DMAAIOCB *dbs = qemu_aio_get(&dma_aiocb_info, NULL, cb, opaque);
217
218 trace_dma_blk_io(dbs, io_func_opaque, offset, (dir == DMA_DIRECTION_TO_DEVICE));
219
220 dbs->acb = NULL;
221 dbs->sg = sg;
222 dbs->ctx = ctx;
223 dbs->offset = offset;
224 dbs->align = align;
225 dbs->sg_cur_index = 0;
226 dbs->sg_cur_byte = 0;
227 dbs->dir = dir;
228 dbs->io_func = io_func;
229 dbs->io_func_opaque = io_func_opaque;
230 dbs->bh = NULL;
231 qemu_iovec_init(&dbs->iov, sg->nsg);
232 dma_blk_cb(dbs, 0);
233 return &dbs->common;
234 }
235
236
237 static
238 BlockAIOCB *dma_blk_read_io_func(int64_t offset, QEMUIOVector *iov,
239 BlockCompletionFunc *cb, void *cb_opaque,
240 void *opaque)
241 {
242 BlockBackend *blk = opaque;
243 return blk_aio_preadv(blk, offset, iov, 0, cb, cb_opaque);
244 }
245
246 BlockAIOCB *dma_blk_read(BlockBackend *blk,
247 QEMUSGList *sg, uint64_t offset, uint32_t align,
248 void (*cb)(void *opaque, int ret), void *opaque)
249 {
250 return dma_blk_io(blk_get_aio_context(blk), sg, offset, align,
251 dma_blk_read_io_func, blk, cb, opaque,
252 DMA_DIRECTION_FROM_DEVICE);
253 }
254
255 static
256 BlockAIOCB *dma_blk_write_io_func(int64_t offset, QEMUIOVector *iov,
257 BlockCompletionFunc *cb, void *cb_opaque,
258 void *opaque)
259 {
260 BlockBackend *blk = opaque;
261 return blk_aio_pwritev(blk, offset, iov, 0, cb, cb_opaque);
262 }
263
264 BlockAIOCB *dma_blk_write(BlockBackend *blk,
265 QEMUSGList *sg, uint64_t offset, uint32_t align,
266 void (*cb)(void *opaque, int ret), void *opaque)
267 {
268 return dma_blk_io(blk_get_aio_context(blk), sg, offset, align,
269 dma_blk_write_io_func, blk, cb, opaque,
270 DMA_DIRECTION_TO_DEVICE);
271 }
272
273
274 static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg,
275 DMADirection dir)
276 {
277 uint64_t resid;
278 int sg_cur_index;
279
280 resid = sg->size;
281 sg_cur_index = 0;
282 len = MIN(len, resid);
283 while (len > 0) {
284 ScatterGatherEntry entry = sg->sg[sg_cur_index++];
285 int32_t xfer = MIN(len, entry.len);
286 dma_memory_rw(sg->as, entry.base, ptr, xfer, dir);
287 ptr += xfer;
288 len -= xfer;
289 resid -= xfer;
290 }
291
292 return resid;
293 }
294
295 uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg)
296 {
297 return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_FROM_DEVICE);
298 }
299
300 uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg)
301 {
302 return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_TO_DEVICE);
303 }
304
305 void dma_acct_start(BlockBackend *blk, BlockAcctCookie *cookie,
306 QEMUSGList *sg, enum BlockAcctType type)
307 {
308 block_acct_start(blk_get_stats(blk), cookie, sg->size, type);
309 }