Merge remote-tracking branch 'remotes/vivier2/tags/trivial-branch-for-6.2-pull-reques...
[qemu.git] / softmmu / dma-helpers.c
1 /*
2 * DMA helper functions
3 *
4 * Copyright (c) 2009,2020 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/trace-root.h"
14 #include "qemu/thread.h"
15 #include "qemu/main-loop.h"
16 #include "sysemu/cpu-timers.h"
17 #include "qemu/range.h"
18
19 /* #define DEBUG_IOMMU */
20
21 MemTxResult dma_memory_set(AddressSpace *as, dma_addr_t addr,
22 uint8_t c, dma_addr_t len)
23 {
24 dma_barrier(as, DMA_DIRECTION_FROM_DEVICE);
25
26 #define FILLBUF_SIZE 512
27 uint8_t fillbuf[FILLBUF_SIZE];
28 int l;
29 MemTxResult error = MEMTX_OK;
30
31 memset(fillbuf, c, FILLBUF_SIZE);
32 while (len > 0) {
33 l = len < FILLBUF_SIZE ? len : FILLBUF_SIZE;
34 error |= address_space_write(as, addr, MEMTXATTRS_UNSPECIFIED,
35 fillbuf, l);
36 len -= l;
37 addr += l;
38 }
39
40 return error;
41 }
42
43 void qemu_sglist_init(QEMUSGList *qsg, DeviceState *dev, int alloc_hint,
44 AddressSpace *as)
45 {
46 qsg->sg = g_malloc(alloc_hint * sizeof(ScatterGatherEntry));
47 qsg->nsg = 0;
48 qsg->nalloc = alloc_hint;
49 qsg->size = 0;
50 qsg->as = as;
51 qsg->dev = dev;
52 object_ref(OBJECT(dev));
53 }
54
55 void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len)
56 {
57 if (qsg->nsg == qsg->nalloc) {
58 qsg->nalloc = 2 * qsg->nalloc + 1;
59 qsg->sg = g_realloc(qsg->sg, qsg->nalloc * sizeof(ScatterGatherEntry));
60 }
61 qsg->sg[qsg->nsg].base = base;
62 qsg->sg[qsg->nsg].len = len;
63 qsg->size += len;
64 ++qsg->nsg;
65 }
66
67 void qemu_sglist_destroy(QEMUSGList *qsg)
68 {
69 object_unref(OBJECT(qsg->dev));
70 g_free(qsg->sg);
71 memset(qsg, 0, sizeof(*qsg));
72 }
73
74 typedef struct {
75 BlockAIOCB common;
76 AioContext *ctx;
77 BlockAIOCB *acb;
78 QEMUSGList *sg;
79 uint32_t align;
80 uint64_t offset;
81 DMADirection dir;
82 int sg_cur_index;
83 dma_addr_t sg_cur_byte;
84 QEMUIOVector iov;
85 QEMUBH *bh;
86 DMAIOFunc *io_func;
87 void *io_func_opaque;
88 } DMAAIOCB;
89
90 static void dma_blk_cb(void *opaque, int ret);
91
92 static void reschedule_dma(void *opaque)
93 {
94 DMAAIOCB *dbs = (DMAAIOCB *)opaque;
95
96 assert(!dbs->acb && dbs->bh);
97 qemu_bh_delete(dbs->bh);
98 dbs->bh = NULL;
99 dma_blk_cb(dbs, 0);
100 }
101
102 static void dma_blk_unmap(DMAAIOCB *dbs)
103 {
104 int i;
105
106 for (i = 0; i < dbs->iov.niov; ++i) {
107 dma_memory_unmap(dbs->sg->as, dbs->iov.iov[i].iov_base,
108 dbs->iov.iov[i].iov_len, dbs->dir,
109 dbs->iov.iov[i].iov_len);
110 }
111 qemu_iovec_reset(&dbs->iov);
112 }
113
114 static void dma_complete(DMAAIOCB *dbs, int ret)
115 {
116 trace_dma_complete(dbs, ret, dbs->common.cb);
117
118 assert(!dbs->acb && !dbs->bh);
119 dma_blk_unmap(dbs);
120 if (dbs->common.cb) {
121 dbs->common.cb(dbs->common.opaque, ret);
122 }
123 qemu_iovec_destroy(&dbs->iov);
124 qemu_aio_unref(dbs);
125 }
126
127 static void dma_blk_cb(void *opaque, int ret)
128 {
129 DMAAIOCB *dbs = (DMAAIOCB *)opaque;
130 dma_addr_t cur_addr, cur_len;
131 void *mem;
132
133 trace_dma_blk_cb(dbs, ret);
134
135 dbs->acb = NULL;
136 dbs->offset += dbs->iov.size;
137
138 if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
139 dma_complete(dbs, ret);
140 return;
141 }
142 dma_blk_unmap(dbs);
143
144 while (dbs->sg_cur_index < dbs->sg->nsg) {
145 cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte;
146 cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte;
147 mem = dma_memory_map(dbs->sg->as, cur_addr, &cur_len, dbs->dir);
148 /*
149 * Make reads deterministic in icount mode. Windows sometimes issues
150 * disk read requests with overlapping SGs. It leads
151 * to non-determinism, because resulting buffer contents may be mixed
152 * from several sectors. This code splits all SGs into several
153 * groups. SGs in every group do not overlap.
154 */
155 if (mem && icount_enabled() && dbs->dir == DMA_DIRECTION_FROM_DEVICE) {
156 int i;
157 for (i = 0 ; i < dbs->iov.niov ; ++i) {
158 if (ranges_overlap((intptr_t)dbs->iov.iov[i].iov_base,
159 dbs->iov.iov[i].iov_len, (intptr_t)mem,
160 cur_len)) {
161 dma_memory_unmap(dbs->sg->as, mem, cur_len,
162 dbs->dir, cur_len);
163 mem = NULL;
164 break;
165 }
166 }
167 }
168 if (!mem)
169 break;
170 qemu_iovec_add(&dbs->iov, mem, cur_len);
171 dbs->sg_cur_byte += cur_len;
172 if (dbs->sg_cur_byte == dbs->sg->sg[dbs->sg_cur_index].len) {
173 dbs->sg_cur_byte = 0;
174 ++dbs->sg_cur_index;
175 }
176 }
177
178 if (dbs->iov.size == 0) {
179 trace_dma_map_wait(dbs);
180 dbs->bh = aio_bh_new(dbs->ctx, reschedule_dma, dbs);
181 cpu_register_map_client(dbs->bh);
182 return;
183 }
184
185 if (!QEMU_IS_ALIGNED(dbs->iov.size, dbs->align)) {
186 qemu_iovec_discard_back(&dbs->iov,
187 QEMU_ALIGN_DOWN(dbs->iov.size, dbs->align));
188 }
189
190 aio_context_acquire(dbs->ctx);
191 dbs->acb = dbs->io_func(dbs->offset, &dbs->iov,
192 dma_blk_cb, dbs, dbs->io_func_opaque);
193 aio_context_release(dbs->ctx);
194 assert(dbs->acb);
195 }
196
197 static void dma_aio_cancel(BlockAIOCB *acb)
198 {
199 DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
200
201 trace_dma_aio_cancel(dbs);
202
203 assert(!(dbs->acb && dbs->bh));
204 if (dbs->acb) {
205 /* This will invoke dma_blk_cb. */
206 blk_aio_cancel_async(dbs->acb);
207 return;
208 }
209
210 if (dbs->bh) {
211 cpu_unregister_map_client(dbs->bh);
212 qemu_bh_delete(dbs->bh);
213 dbs->bh = NULL;
214 }
215 if (dbs->common.cb) {
216 dbs->common.cb(dbs->common.opaque, -ECANCELED);
217 }
218 }
219
220 static AioContext *dma_get_aio_context(BlockAIOCB *acb)
221 {
222 DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
223
224 return dbs->ctx;
225 }
226
227 static const AIOCBInfo dma_aiocb_info = {
228 .aiocb_size = sizeof(DMAAIOCB),
229 .cancel_async = dma_aio_cancel,
230 .get_aio_context = dma_get_aio_context,
231 };
232
233 BlockAIOCB *dma_blk_io(AioContext *ctx,
234 QEMUSGList *sg, uint64_t offset, uint32_t align,
235 DMAIOFunc *io_func, void *io_func_opaque,
236 BlockCompletionFunc *cb,
237 void *opaque, DMADirection dir)
238 {
239 DMAAIOCB *dbs = qemu_aio_get(&dma_aiocb_info, NULL, cb, opaque);
240
241 trace_dma_blk_io(dbs, io_func_opaque, offset, (dir == DMA_DIRECTION_TO_DEVICE));
242
243 dbs->acb = NULL;
244 dbs->sg = sg;
245 dbs->ctx = ctx;
246 dbs->offset = offset;
247 dbs->align = align;
248 dbs->sg_cur_index = 0;
249 dbs->sg_cur_byte = 0;
250 dbs->dir = dir;
251 dbs->io_func = io_func;
252 dbs->io_func_opaque = io_func_opaque;
253 dbs->bh = NULL;
254 qemu_iovec_init(&dbs->iov, sg->nsg);
255 dma_blk_cb(dbs, 0);
256 return &dbs->common;
257 }
258
259
260 static
261 BlockAIOCB *dma_blk_read_io_func(int64_t offset, QEMUIOVector *iov,
262 BlockCompletionFunc *cb, void *cb_opaque,
263 void *opaque)
264 {
265 BlockBackend *blk = opaque;
266 return blk_aio_preadv(blk, offset, iov, 0, cb, cb_opaque);
267 }
268
269 BlockAIOCB *dma_blk_read(BlockBackend *blk,
270 QEMUSGList *sg, uint64_t offset, uint32_t align,
271 void (*cb)(void *opaque, int ret), void *opaque)
272 {
273 return dma_blk_io(blk_get_aio_context(blk), sg, offset, align,
274 dma_blk_read_io_func, blk, cb, opaque,
275 DMA_DIRECTION_FROM_DEVICE);
276 }
277
278 static
279 BlockAIOCB *dma_blk_write_io_func(int64_t offset, QEMUIOVector *iov,
280 BlockCompletionFunc *cb, void *cb_opaque,
281 void *opaque)
282 {
283 BlockBackend *blk = opaque;
284 return blk_aio_pwritev(blk, offset, iov, 0, cb, cb_opaque);
285 }
286
287 BlockAIOCB *dma_blk_write(BlockBackend *blk,
288 QEMUSGList *sg, uint64_t offset, uint32_t align,
289 void (*cb)(void *opaque, int ret), void *opaque)
290 {
291 return dma_blk_io(blk_get_aio_context(blk), sg, offset, align,
292 dma_blk_write_io_func, blk, cb, opaque,
293 DMA_DIRECTION_TO_DEVICE);
294 }
295
296
297 static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg,
298 DMADirection dir)
299 {
300 uint64_t resid;
301 int sg_cur_index;
302
303 resid = sg->size;
304 sg_cur_index = 0;
305 len = MIN(len, resid);
306 while (len > 0) {
307 ScatterGatherEntry entry = sg->sg[sg_cur_index++];
308 int32_t xfer = MIN(len, entry.len);
309 dma_memory_rw(sg->as, entry.base, ptr, xfer, dir);
310 ptr += xfer;
311 len -= xfer;
312 resid -= xfer;
313 }
314
315 return resid;
316 }
317
318 uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg)
319 {
320 return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_FROM_DEVICE);
321 }
322
323 uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg)
324 {
325 return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_TO_DEVICE);
326 }
327
328 void dma_acct_start(BlockBackend *blk, BlockAcctCookie *cookie,
329 QEMUSGList *sg, enum BlockAcctType type)
330 {
331 block_acct_start(blk_get_stats(blk), cookie, sg->size, type);
332 }
333
334 uint64_t dma_aligned_pow2_mask(uint64_t start, uint64_t end, int max_addr_bits)
335 {
336 uint64_t max_mask = UINT64_MAX, addr_mask = end - start;
337 uint64_t alignment_mask, size_mask;
338
339 if (max_addr_bits != 64) {
340 max_mask = (1ULL << max_addr_bits) - 1;
341 }
342
343 alignment_mask = start ? (start & -start) - 1 : max_mask;
344 alignment_mask = MIN(alignment_mask, max_mask);
345 size_mask = MIN(addr_mask, max_mask);
346
347 if (alignment_mask <= size_mask) {
348 /* Increase the alignment of start */
349 return alignment_mask;
350 } else {
351 /* Find the largest page mask from size */
352 if (addr_mask == UINT64_MAX) {
353 return UINT64_MAX;
354 }
355 return (1ULL << (63 - clz64(addr_mask + 1))) - 1;
356 }
357 }
358