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1 /*
2 * Virtio Support
3 *
4 * Copyright IBM, Corp. 2007
5 *
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
11 *
12 */
13
14 #include <inttypes.h>
15
16 #include "virtio.h"
17 #include "sysemu.h"
18
19 /* The alignment to use between consumer and producer parts of vring.
20 * x86 pagesize again. */
21 #define VIRTIO_PCI_VRING_ALIGN 4096
22
23 /* QEMU doesn't strictly need write barriers since everything runs in
24 * lock-step. We'll leave the calls to wmb() in though to make it obvious for
25 * KVM or if kqemu gets SMP support.
26 * In any case, we must prevent the compiler from reordering the code.
27 * TODO: we likely need some rmb()/mb() as well.
28 */
29
30 #define wmb() __asm__ __volatile__("": : :"memory")
31
32 typedef struct VRingDesc
33 {
34 uint64_t addr;
35 uint32_t len;
36 uint16_t flags;
37 uint16_t next;
38 } VRingDesc;
39
40 typedef struct VRingAvail
41 {
42 uint16_t flags;
43 uint16_t idx;
44 uint16_t ring[0];
45 } VRingAvail;
46
47 typedef struct VRingUsedElem
48 {
49 uint32_t id;
50 uint32_t len;
51 } VRingUsedElem;
52
53 typedef struct VRingUsed
54 {
55 uint16_t flags;
56 uint16_t idx;
57 VRingUsedElem ring[0];
58 } VRingUsed;
59
60 typedef struct VRing
61 {
62 unsigned int num;
63 target_phys_addr_t desc;
64 target_phys_addr_t avail;
65 target_phys_addr_t used;
66 } VRing;
67
68 struct VirtQueue
69 {
70 VRing vring;
71 target_phys_addr_t pa;
72 uint16_t last_avail_idx;
73 int inuse;
74 uint16_t vector;
75 void (*handle_output)(VirtIODevice *vdev, VirtQueue *vq);
76 };
77
78 #define VIRTIO_PCI_QUEUE_MAX 16
79
80 /* virt queue functions */
81 static void virtqueue_init(VirtQueue *vq)
82 {
83 target_phys_addr_t pa = vq->pa;
84
85 vq->vring.desc = pa;
86 vq->vring.avail = pa + vq->vring.num * sizeof(VRingDesc);
87 vq->vring.used = vring_align(vq->vring.avail +
88 offsetof(VRingAvail, ring[vq->vring.num]),
89 VIRTIO_PCI_VRING_ALIGN);
90 }
91
92 static inline uint64_t vring_desc_addr(target_phys_addr_t desc_pa, int i)
93 {
94 target_phys_addr_t pa;
95 pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, addr);
96 return ldq_phys(pa);
97 }
98
99 static inline uint32_t vring_desc_len(target_phys_addr_t desc_pa, int i)
100 {
101 target_phys_addr_t pa;
102 pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, len);
103 return ldl_phys(pa);
104 }
105
106 static inline uint16_t vring_desc_flags(target_phys_addr_t desc_pa, int i)
107 {
108 target_phys_addr_t pa;
109 pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, flags);
110 return lduw_phys(pa);
111 }
112
113 static inline uint16_t vring_desc_next(target_phys_addr_t desc_pa, int i)
114 {
115 target_phys_addr_t pa;
116 pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, next);
117 return lduw_phys(pa);
118 }
119
120 static inline uint16_t vring_avail_flags(VirtQueue *vq)
121 {
122 target_phys_addr_t pa;
123 pa = vq->vring.avail + offsetof(VRingAvail, flags);
124 return lduw_phys(pa);
125 }
126
127 static inline uint16_t vring_avail_idx(VirtQueue *vq)
128 {
129 target_phys_addr_t pa;
130 pa = vq->vring.avail + offsetof(VRingAvail, idx);
131 return lduw_phys(pa);
132 }
133
134 static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
135 {
136 target_phys_addr_t pa;
137 pa = vq->vring.avail + offsetof(VRingAvail, ring[i]);
138 return lduw_phys(pa);
139 }
140
141 static inline void vring_used_ring_id(VirtQueue *vq, int i, uint32_t val)
142 {
143 target_phys_addr_t pa;
144 pa = vq->vring.used + offsetof(VRingUsed, ring[i].id);
145 stl_phys(pa, val);
146 }
147
148 static inline void vring_used_ring_len(VirtQueue *vq, int i, uint32_t val)
149 {
150 target_phys_addr_t pa;
151 pa = vq->vring.used + offsetof(VRingUsed, ring[i].len);
152 stl_phys(pa, val);
153 }
154
155 static uint16_t vring_used_idx(VirtQueue *vq)
156 {
157 target_phys_addr_t pa;
158 pa = vq->vring.used + offsetof(VRingUsed, idx);
159 return lduw_phys(pa);
160 }
161
162 static inline void vring_used_idx_increment(VirtQueue *vq, uint16_t val)
163 {
164 target_phys_addr_t pa;
165 pa = vq->vring.used + offsetof(VRingUsed, idx);
166 stw_phys(pa, vring_used_idx(vq) + val);
167 }
168
169 static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
170 {
171 target_phys_addr_t pa;
172 pa = vq->vring.used + offsetof(VRingUsed, flags);
173 stw_phys(pa, lduw_phys(pa) | mask);
174 }
175
176 static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
177 {
178 target_phys_addr_t pa;
179 pa = vq->vring.used + offsetof(VRingUsed, flags);
180 stw_phys(pa, lduw_phys(pa) & ~mask);
181 }
182
183 void virtio_queue_set_notification(VirtQueue *vq, int enable)
184 {
185 if (enable)
186 vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
187 else
188 vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
189 }
190
191 int virtio_queue_ready(VirtQueue *vq)
192 {
193 return vq->vring.avail != 0;
194 }
195
196 int virtio_queue_empty(VirtQueue *vq)
197 {
198 return vring_avail_idx(vq) == vq->last_avail_idx;
199 }
200
201 void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
202 unsigned int len, unsigned int idx)
203 {
204 unsigned int offset;
205 int i;
206
207 offset = 0;
208 for (i = 0; i < elem->in_num; i++) {
209 size_t size = MIN(len - offset, elem->in_sg[i].iov_len);
210
211 cpu_physical_memory_unmap(elem->in_sg[i].iov_base,
212 elem->in_sg[i].iov_len,
213 1, size);
214
215 offset += elem->in_sg[i].iov_len;
216 }
217
218 for (i = 0; i < elem->out_num; i++)
219 cpu_physical_memory_unmap(elem->out_sg[i].iov_base,
220 elem->out_sg[i].iov_len,
221 0, elem->out_sg[i].iov_len);
222
223 idx = (idx + vring_used_idx(vq)) % vq->vring.num;
224
225 /* Get a pointer to the next entry in the used ring. */
226 vring_used_ring_id(vq, idx, elem->index);
227 vring_used_ring_len(vq, idx, len);
228 }
229
230 void virtqueue_flush(VirtQueue *vq, unsigned int count)
231 {
232 /* Make sure buffer is written before we update index. */
233 wmb();
234 vring_used_idx_increment(vq, count);
235 vq->inuse -= count;
236 }
237
238 void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
239 unsigned int len)
240 {
241 virtqueue_fill(vq, elem, len, 0);
242 virtqueue_flush(vq, 1);
243 }
244
245 static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx)
246 {
247 uint16_t num_heads = vring_avail_idx(vq) - idx;
248
249 /* Check it isn't doing very strange things with descriptor numbers. */
250 if (num_heads > vq->vring.num) {
251 fprintf(stderr, "Guest moved used index from %u to %u",
252 idx, vring_avail_idx(vq));
253 exit(1);
254 }
255
256 return num_heads;
257 }
258
259 static unsigned int virtqueue_get_head(VirtQueue *vq, unsigned int idx)
260 {
261 unsigned int head;
262
263 /* Grab the next descriptor number they're advertising, and increment
264 * the index we've seen. */
265 head = vring_avail_ring(vq, idx % vq->vring.num);
266
267 /* If their number is silly, that's a fatal mistake. */
268 if (head >= vq->vring.num) {
269 fprintf(stderr, "Guest says index %u is available", head);
270 exit(1);
271 }
272
273 return head;
274 }
275
276 static unsigned virtqueue_next_desc(target_phys_addr_t desc_pa,
277 unsigned int i, unsigned int max)
278 {
279 unsigned int next;
280
281 /* If this descriptor says it doesn't chain, we're done. */
282 if (!(vring_desc_flags(desc_pa, i) & VRING_DESC_F_NEXT))
283 return max;
284
285 /* Check they're not leading us off end of descriptors. */
286 next = vring_desc_next(desc_pa, i);
287 /* Make sure compiler knows to grab that: we don't want it changing! */
288 wmb();
289
290 if (next >= max) {
291 fprintf(stderr, "Desc next is %u", next);
292 exit(1);
293 }
294
295 return next;
296 }
297
298 int virtqueue_avail_bytes(VirtQueue *vq, int in_bytes, int out_bytes)
299 {
300 unsigned int idx;
301 int total_bufs, in_total, out_total;
302
303 idx = vq->last_avail_idx;
304
305 total_bufs = in_total = out_total = 0;
306 while (virtqueue_num_heads(vq, idx)) {
307 unsigned int max, num_bufs, indirect = 0;
308 target_phys_addr_t desc_pa;
309 int i;
310
311 max = vq->vring.num;
312 num_bufs = total_bufs;
313 i = virtqueue_get_head(vq, idx++);
314 desc_pa = vq->vring.desc;
315
316 if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_INDIRECT) {
317 if (vring_desc_len(desc_pa, i) % sizeof(VRingDesc)) {
318 fprintf(stderr, "Invalid size for indirect buffer table\n");
319 exit(1);
320 }
321
322 /* If we've got too many, that implies a descriptor loop. */
323 if (num_bufs >= max) {
324 fprintf(stderr, "Looped descriptor");
325 exit(1);
326 }
327
328 /* loop over the indirect descriptor table */
329 indirect = 1;
330 max = vring_desc_len(desc_pa, i) / sizeof(VRingDesc);
331 num_bufs = i = 0;
332 desc_pa = vring_desc_addr(desc_pa, i);
333 }
334
335 do {
336 /* If we've got too many, that implies a descriptor loop. */
337 if (++num_bufs > max) {
338 fprintf(stderr, "Looped descriptor");
339 exit(1);
340 }
341
342 if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_WRITE) {
343 if (in_bytes > 0 &&
344 (in_total += vring_desc_len(desc_pa, i)) >= in_bytes)
345 return 1;
346 } else {
347 if (out_bytes > 0 &&
348 (out_total += vring_desc_len(desc_pa, i)) >= out_bytes)
349 return 1;
350 }
351 } while ((i = virtqueue_next_desc(desc_pa, i, max)) != max);
352
353 if (!indirect)
354 total_bufs = num_bufs;
355 else
356 total_bufs++;
357 }
358
359 return 0;
360 }
361
362 int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
363 {
364 unsigned int i, head, max;
365 target_phys_addr_t desc_pa = vq->vring.desc;
366 target_phys_addr_t len;
367
368 if (!virtqueue_num_heads(vq, vq->last_avail_idx))
369 return 0;
370
371 /* When we start there are none of either input nor output. */
372 elem->out_num = elem->in_num = 0;
373
374 max = vq->vring.num;
375
376 i = head = virtqueue_get_head(vq, vq->last_avail_idx++);
377
378 if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_INDIRECT) {
379 if (vring_desc_len(desc_pa, i) % sizeof(VRingDesc)) {
380 fprintf(stderr, "Invalid size for indirect buffer table\n");
381 exit(1);
382 }
383
384 /* loop over the indirect descriptor table */
385 max = vring_desc_len(desc_pa, i) / sizeof(VRingDesc);
386 desc_pa = vring_desc_addr(desc_pa, i);
387 i = 0;
388 }
389
390 do {
391 struct iovec *sg;
392 int is_write = 0;
393
394 if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_WRITE) {
395 elem->in_addr[elem->in_num] = vring_desc_addr(desc_pa, i);
396 sg = &elem->in_sg[elem->in_num++];
397 is_write = 1;
398 } else
399 sg = &elem->out_sg[elem->out_num++];
400
401 /* Grab the first descriptor, and check it's OK. */
402 sg->iov_len = vring_desc_len(desc_pa, i);
403 len = sg->iov_len;
404
405 sg->iov_base = cpu_physical_memory_map(vring_desc_addr(desc_pa, i),
406 &len, is_write);
407
408 if (sg->iov_base == NULL || len != sg->iov_len) {
409 fprintf(stderr, "virtio: trying to map MMIO memory\n");
410 exit(1);
411 }
412
413 /* If we've got too many, that implies a descriptor loop. */
414 if ((elem->in_num + elem->out_num) > max) {
415 fprintf(stderr, "Looped descriptor");
416 exit(1);
417 }
418 } while ((i = virtqueue_next_desc(desc_pa, i, max)) != max);
419
420 elem->index = head;
421
422 vq->inuse++;
423
424 return elem->in_num + elem->out_num;
425 }
426
427 /* virtio device */
428 static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector)
429 {
430 if (vdev->binding->notify) {
431 vdev->binding->notify(vdev->binding_opaque, vector);
432 }
433 }
434
435 void virtio_update_irq(VirtIODevice *vdev)
436 {
437 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
438 }
439
440 void virtio_reset(void *opaque)
441 {
442 VirtIODevice *vdev = opaque;
443 int i;
444
445 if (vdev->reset)
446 vdev->reset(vdev);
447
448 vdev->features = 0;
449 vdev->queue_sel = 0;
450 vdev->status = 0;
451 vdev->isr = 0;
452 vdev->config_vector = VIRTIO_NO_VECTOR;
453 virtio_notify_vector(vdev, vdev->config_vector);
454
455 for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
456 vdev->vq[i].vring.desc = 0;
457 vdev->vq[i].vring.avail = 0;
458 vdev->vq[i].vring.used = 0;
459 vdev->vq[i].last_avail_idx = 0;
460 vdev->vq[i].pa = 0;
461 vdev->vq[i].vector = VIRTIO_NO_VECTOR;
462 }
463 }
464
465 uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr)
466 {
467 uint8_t val;
468
469 vdev->get_config(vdev, vdev->config);
470
471 if (addr > (vdev->config_len - sizeof(val)))
472 return (uint32_t)-1;
473
474 memcpy(&val, vdev->config + addr, sizeof(val));
475 return val;
476 }
477
478 uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr)
479 {
480 uint16_t val;
481
482 vdev->get_config(vdev, vdev->config);
483
484 if (addr > (vdev->config_len - sizeof(val)))
485 return (uint32_t)-1;
486
487 memcpy(&val, vdev->config + addr, sizeof(val));
488 return val;
489 }
490
491 uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr)
492 {
493 uint32_t val;
494
495 vdev->get_config(vdev, vdev->config);
496
497 if (addr > (vdev->config_len - sizeof(val)))
498 return (uint32_t)-1;
499
500 memcpy(&val, vdev->config + addr, sizeof(val));
501 return val;
502 }
503
504 void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data)
505 {
506 uint8_t val = data;
507
508 if (addr > (vdev->config_len - sizeof(val)))
509 return;
510
511 memcpy(vdev->config + addr, &val, sizeof(val));
512
513 if (vdev->set_config)
514 vdev->set_config(vdev, vdev->config);
515 }
516
517 void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data)
518 {
519 uint16_t val = data;
520
521 if (addr > (vdev->config_len - sizeof(val)))
522 return;
523
524 memcpy(vdev->config + addr, &val, sizeof(val));
525
526 if (vdev->set_config)
527 vdev->set_config(vdev, vdev->config);
528 }
529
530 void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
531 {
532 uint32_t val = data;
533
534 if (addr > (vdev->config_len - sizeof(val)))
535 return;
536
537 memcpy(vdev->config + addr, &val, sizeof(val));
538
539 if (vdev->set_config)
540 vdev->set_config(vdev, vdev->config);
541 }
542
543 void virtio_queue_set_addr(VirtIODevice *vdev, int n, target_phys_addr_t addr)
544 {
545 vdev->vq[n].pa = addr;
546 virtqueue_init(&vdev->vq[n]);
547 }
548
549 target_phys_addr_t virtio_queue_get_addr(VirtIODevice *vdev, int n)
550 {
551 return vdev->vq[n].pa;
552 }
553
554 int virtio_queue_get_num(VirtIODevice *vdev, int n)
555 {
556 return vdev->vq[n].vring.num;
557 }
558
559 void virtio_queue_notify(VirtIODevice *vdev, int n)
560 {
561 if (n < VIRTIO_PCI_QUEUE_MAX && vdev->vq[n].vring.desc) {
562 vdev->vq[n].handle_output(vdev, &vdev->vq[n]);
563 }
564 }
565
566 uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)
567 {
568 return n < VIRTIO_PCI_QUEUE_MAX ? vdev->vq[n].vector :
569 VIRTIO_NO_VECTOR;
570 }
571
572 void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
573 {
574 if (n < VIRTIO_PCI_QUEUE_MAX)
575 vdev->vq[n].vector = vector;
576 }
577
578 VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
579 void (*handle_output)(VirtIODevice *, VirtQueue *))
580 {
581 int i;
582
583 for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
584 if (vdev->vq[i].vring.num == 0)
585 break;
586 }
587
588 if (i == VIRTIO_PCI_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
589 abort();
590
591 vdev->vq[i].vring.num = queue_size;
592 vdev->vq[i].handle_output = handle_output;
593
594 return &vdev->vq[i];
595 }
596
597 void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
598 {
599 /* Always notify when queue is empty (when feature acknowledge) */
600 if ((vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT) &&
601 (!(vdev->features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) ||
602 (vq->inuse || vring_avail_idx(vq) != vq->last_avail_idx)))
603 return;
604
605 vdev->isr |= 0x01;
606 virtio_notify_vector(vdev, vq->vector);
607 }
608
609 void virtio_notify_config(VirtIODevice *vdev)
610 {
611 if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK))
612 return;
613
614 vdev->isr |= 0x03;
615 virtio_notify_vector(vdev, vdev->config_vector);
616 }
617
618 void virtio_save(VirtIODevice *vdev, QEMUFile *f)
619 {
620 int i;
621
622 if (vdev->binding->save_config)
623 vdev->binding->save_config(vdev->binding_opaque, f);
624
625 qemu_put_8s(f, &vdev->status);
626 qemu_put_8s(f, &vdev->isr);
627 qemu_put_be16s(f, &vdev->queue_sel);
628 qemu_put_be32s(f, &vdev->features);
629 qemu_put_be32(f, vdev->config_len);
630 qemu_put_buffer(f, vdev->config, vdev->config_len);
631
632 for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
633 if (vdev->vq[i].vring.num == 0)
634 break;
635 }
636
637 qemu_put_be32(f, i);
638
639 for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
640 if (vdev->vq[i].vring.num == 0)
641 break;
642
643 qemu_put_be32(f, vdev->vq[i].vring.num);
644 qemu_put_be64(f, vdev->vq[i].pa);
645 qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
646 if (vdev->binding->save_queue)
647 vdev->binding->save_queue(vdev->binding_opaque, i, f);
648 }
649 }
650
651 int virtio_load(VirtIODevice *vdev, QEMUFile *f)
652 {
653 int num, i, ret;
654
655 if (vdev->binding->load_config) {
656 ret = vdev->binding->load_config(vdev->binding_opaque, f);
657 if (ret)
658 return ret;
659 }
660
661 qemu_get_8s(f, &vdev->status);
662 qemu_get_8s(f, &vdev->isr);
663 qemu_get_be16s(f, &vdev->queue_sel);
664 qemu_get_be32s(f, &vdev->features);
665 vdev->config_len = qemu_get_be32(f);
666 qemu_get_buffer(f, vdev->config, vdev->config_len);
667
668 num = qemu_get_be32(f);
669
670 for (i = 0; i < num; i++) {
671 vdev->vq[i].vring.num = qemu_get_be32(f);
672 vdev->vq[i].pa = qemu_get_be64(f);
673 qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
674
675 if (vdev->vq[i].pa) {
676 virtqueue_init(&vdev->vq[i]);
677 }
678 if (vdev->binding->load_queue) {
679 ret = vdev->binding->load_queue(vdev->binding_opaque, i, f);
680 if (ret)
681 return ret;
682 }
683 }
684
685 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
686 return 0;
687 }
688
689 void virtio_cleanup(VirtIODevice *vdev)
690 {
691 if (vdev->config)
692 qemu_free(vdev->config);
693 qemu_free(vdev->vq);
694 }
695
696 VirtIODevice *virtio_common_init(const char *name, uint16_t device_id,
697 size_t config_size, size_t struct_size)
698 {
699 VirtIODevice *vdev;
700 int i;
701
702 vdev = qemu_mallocz(struct_size);
703
704 vdev->device_id = device_id;
705 vdev->status = 0;
706 vdev->isr = 0;
707 vdev->queue_sel = 0;
708 vdev->config_vector = VIRTIO_NO_VECTOR;
709 vdev->vq = qemu_mallocz(sizeof(VirtQueue) * VIRTIO_PCI_QUEUE_MAX);
710 for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++)
711 vdev->vq[i].vector = VIRTIO_NO_VECTOR;
712
713 vdev->name = name;
714 vdev->config_len = config_size;
715 if (vdev->config_len)
716 vdev->config = qemu_mallocz(config_size);
717 else
718 vdev->config = NULL;
719
720 return vdev;
721 }
722
723 void virtio_bind_device(VirtIODevice *vdev, const VirtIOBindings *binding,
724 void *opaque)
725 {
726 vdev->binding = binding;
727 vdev->binding_opaque = opaque;
728 }