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Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[cris-mirror.git] / drivers / vfio / pci / vfio_pci_intrs.c
blobe9ea3fef144a3164ab002bc013d1c36e30a7be45
1 /*
2 * VFIO PCI interrupt handling
3 *
4 * Copyright (C) 2012 Red Hat, Inc. All rights reserved.
5 * Author: Alex Williamson <alex.williamson@redhat.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * Derived from original vfio:
12 * Copyright 2010 Cisco Systems, Inc. All rights reserved.
13 * Author: Tom Lyon, pugs@cisco.com
14 */
15
16 #include <linux/device.h>
17 #include <linux/interrupt.h>
18 #include <linux/eventfd.h>
19 #include <linux/msi.h>
20 #include <linux/pci.h>
21 #include <linux/file.h>
22 #include <linux/vfio.h>
23 #include <linux/wait.h>
24 #include <linux/slab.h>
25
26 #include "vfio_pci_private.h"
27
28 /*
29 * INTx
30 */
31 static void vfio_send_intx_eventfd(void *opaque, void *unused)
32 {
33 struct vfio_pci_device *vdev = opaque;
34
35 if (likely(is_intx(vdev) && !vdev->virq_disabled))
36 eventfd_signal(vdev->ctx[0].trigger, 1);
37 }
38
39 void vfio_pci_intx_mask(struct vfio_pci_device *vdev)
40 {
41 struct pci_dev *pdev = vdev->pdev;
42 unsigned long flags;
43
44 spin_lock_irqsave(&vdev->irqlock, flags);
45
46 /*
47 * Masking can come from interrupt, ioctl, or config space
48 * via INTx disable. The latter means this can get called
49 * even when not using intx delivery. In this case, just
50 * try to have the physical bit follow the virtual bit.
51 */
52 if (unlikely(!is_intx(vdev))) {
53 if (vdev->pci_2_3)
54 pci_intx(pdev, 0);
55 } else if (!vdev->ctx[0].masked) {
56 /*
57 * Can't use check_and_mask here because we always want to
58 * mask, not just when something is pending.
59 */
60 if (vdev->pci_2_3)
61 pci_intx(pdev, 0);
62 else
63 disable_irq_nosync(pdev->irq);
64
65 vdev->ctx[0].masked = true;
66 }
67
68 spin_unlock_irqrestore(&vdev->irqlock, flags);
69 }
70
71 /*
72 * If this is triggered by an eventfd, we can't call eventfd_signal
73 * or else we'll deadlock on the eventfd wait queue. Return >0 when
74 * a signal is necessary, which can then be handled via a work queue
75 * or directly depending on the caller.
76 */
77 static int vfio_pci_intx_unmask_handler(void *opaque, void *unused)
78 {
79 struct vfio_pci_device *vdev = opaque;
80 struct pci_dev *pdev = vdev->pdev;
81 unsigned long flags;
82 int ret = 0;
83
84 spin_lock_irqsave(&vdev->irqlock, flags);
85
86 /*
87 * Unmasking comes from ioctl or config, so again, have the
88 * physical bit follow the virtual even when not using INTx.
89 */
90 if (unlikely(!is_intx(vdev))) {
91 if (vdev->pci_2_3)
92 pci_intx(pdev, 1);
93 } else if (vdev->ctx[0].masked && !vdev->virq_disabled) {
94 /*
95 * A pending interrupt here would immediately trigger,
96 * but we can avoid that overhead by just re-sending
97 * the interrupt to the user.
98 */
99 if (vdev->pci_2_3) {
100 if (!pci_check_and_unmask_intx(pdev))
101 ret = 1;
102 } else
103 enable_irq(pdev->irq);
104
105 vdev->ctx[0].masked = (ret > 0);
106 }
107
108 spin_unlock_irqrestore(&vdev->irqlock, flags);
109
110 return ret;
111 }
112
113 void vfio_pci_intx_unmask(struct vfio_pci_device *vdev)
114 {
115 if (vfio_pci_intx_unmask_handler(vdev, NULL) > 0)
116 vfio_send_intx_eventfd(vdev, NULL);
117 }
118
119 static irqreturn_t vfio_intx_handler(int irq, void *dev_id)
120 {
121 struct vfio_pci_device *vdev = dev_id;
122 unsigned long flags;
123 int ret = IRQ_NONE;
124
125 spin_lock_irqsave(&vdev->irqlock, flags);
126
127 if (!vdev->pci_2_3) {
128 disable_irq_nosync(vdev->pdev->irq);
129 vdev->ctx[0].masked = true;
130 ret = IRQ_HANDLED;
131 } else if (!vdev->ctx[0].masked && /* may be shared */
132 pci_check_and_mask_intx(vdev->pdev)) {
133 vdev->ctx[0].masked = true;
134 ret = IRQ_HANDLED;
135 }
136
137 spin_unlock_irqrestore(&vdev->irqlock, flags);
138
139 if (ret == IRQ_HANDLED)
140 vfio_send_intx_eventfd(vdev, NULL);
141
142 return ret;
143 }
144
145 static int vfio_intx_enable(struct vfio_pci_device *vdev)
146 {
147 if (!is_irq_none(vdev))
148 return -EINVAL;
149
150 if (!vdev->pdev->irq)
151 return -ENODEV;
152
153 vdev->ctx = kzalloc(sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL);
154 if (!vdev->ctx)
155 return -ENOMEM;
156
157 vdev->num_ctx = 1;
158
159 /*
160 * If the virtual interrupt is masked, restore it. Devices
161 * supporting DisINTx can be masked at the hardware level
162 * here, non-PCI-2.3 devices will have to wait until the
163 * interrupt is enabled.
164 */
165 vdev->ctx[0].masked = vdev->virq_disabled;
166 if (vdev->pci_2_3)
167 pci_intx(vdev->pdev, !vdev->ctx[0].masked);
168
169 vdev->irq_type = VFIO_PCI_INTX_IRQ_INDEX;
170
171 return 0;
172 }
173
174 static int vfio_intx_set_signal(struct vfio_pci_device *vdev, int fd)
175 {
176 struct pci_dev *pdev = vdev->pdev;
177 unsigned long irqflags = IRQF_SHARED;
178 struct eventfd_ctx *trigger;
179 unsigned long flags;
180 int ret;
181
182 if (vdev->ctx[0].trigger) {
183 free_irq(pdev->irq, vdev);
184 kfree(vdev->ctx[0].name);
185 eventfd_ctx_put(vdev->ctx[0].trigger);
186 vdev->ctx[0].trigger = NULL;
187 }
188
189 if (fd < 0) /* Disable only */
190 return 0;
191
192 vdev->ctx[0].name = kasprintf(GFP_KERNEL, "vfio-intx(%s)",
193 pci_name(pdev));
194 if (!vdev->ctx[0].name)
195 return -ENOMEM;
196
197 trigger = eventfd_ctx_fdget(fd);
198 if (IS_ERR(trigger)) {
199 kfree(vdev->ctx[0].name);
200 return PTR_ERR(trigger);
201 }
202
203 vdev->ctx[0].trigger = trigger;
204
205 if (!vdev->pci_2_3)
206 irqflags = 0;
207
208 ret = request_irq(pdev->irq, vfio_intx_handler,
209 irqflags, vdev->ctx[0].name, vdev);
210 if (ret) {
211 vdev->ctx[0].trigger = NULL;
212 kfree(vdev->ctx[0].name);
213 eventfd_ctx_put(trigger);
214 return ret;
215 }
216
217 /*
218 * INTx disable will stick across the new irq setup,
219 * disable_irq won't.
220 */
221 spin_lock_irqsave(&vdev->irqlock, flags);
222 if (!vdev->pci_2_3 && vdev->ctx[0].masked)
223 disable_irq_nosync(pdev->irq);
224 spin_unlock_irqrestore(&vdev->irqlock, flags);
225
226 return 0;
227 }
228
229 static void vfio_intx_disable(struct vfio_pci_device *vdev)
230 {
231 vfio_intx_set_signal(vdev, -1);
232 vfio_virqfd_disable(&vdev->ctx[0].unmask);
233 vfio_virqfd_disable(&vdev->ctx[0].mask);
234 vdev->irq_type = VFIO_PCI_NUM_IRQS;
235 vdev->num_ctx = 0;
236 kfree(vdev->ctx);
237 }
238
239 /*
240 * MSI/MSI-X
241 */
242 static irqreturn_t vfio_msihandler(int irq, void *arg)
243 {
244 struct eventfd_ctx *trigger = arg;
245
246 eventfd_signal(trigger, 1);
247 return IRQ_HANDLED;
248 }
249
250 static int vfio_msi_enable(struct vfio_pci_device *vdev, int nvec, bool msix)
251 {
252 struct pci_dev *pdev = vdev->pdev;
253 int ret;
254
255 if (!is_irq_none(vdev))
256 return -EINVAL;
257
258 vdev->ctx = kzalloc(nvec * sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL);
259 if (!vdev->ctx)
260 return -ENOMEM;
261
262 if (msix) {
263 int i;
264
265 vdev->msix = kzalloc(nvec * sizeof(struct msix_entry),
266 GFP_KERNEL);
267 if (!vdev->msix) {
268 kfree(vdev->ctx);
269 return -ENOMEM;
270 }
271
272 for (i = 0; i < nvec; i++)
273 vdev->msix[i].entry = i;
274
275 ret = pci_enable_msix_range(pdev, vdev->msix, 1, nvec);
276 if (ret < nvec) {
277 if (ret > 0)
278 pci_disable_msix(pdev);
279 kfree(vdev->msix);
280 kfree(vdev->ctx);
281 return ret;
282 }
283 } else {
284 ret = pci_enable_msi_range(pdev, 1, nvec);
285 if (ret < nvec) {
286 if (ret > 0)
287 pci_disable_msi(pdev);
288 kfree(vdev->ctx);
289 return ret;
290 }
291 }
292
293 vdev->num_ctx = nvec;
294 vdev->irq_type = msix ? VFIO_PCI_MSIX_IRQ_INDEX :
295 VFIO_PCI_MSI_IRQ_INDEX;
296
297 if (!msix) {
298 /*
299 * Compute the virtual hardware field for max msi vectors -
300 * it is the log base 2 of the number of vectors.
301 */
302 vdev->msi_qmax = fls(nvec * 2 - 1) - 1;
303 }
304
305 return 0;
306 }
307
308 static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev,
309 int vector, int fd, bool msix)
310 {
311 struct pci_dev *pdev = vdev->pdev;
312 struct eventfd_ctx *trigger;
313 int irq, ret;
314
315 if (vector < 0 || vector >= vdev->num_ctx)
316 return -EINVAL;
317
318 irq = msix ? vdev->msix[vector].vector : pdev->irq + vector;
319
320 if (vdev->ctx[vector].trigger) {
321 free_irq(irq, vdev->ctx[vector].trigger);
322 irq_bypass_unregister_producer(&vdev->ctx[vector].producer);
323 kfree(vdev->ctx[vector].name);
324 eventfd_ctx_put(vdev->ctx[vector].trigger);
325 vdev->ctx[vector].trigger = NULL;
326 }
327
328 if (fd < 0)
329 return 0;
330
331 vdev->ctx[vector].name = kasprintf(GFP_KERNEL, "vfio-msi%s[%d](%s)",
332 msix ? "x" : "", vector,
333 pci_name(pdev));
334 if (!vdev->ctx[vector].name)
335 return -ENOMEM;
336
337 trigger = eventfd_ctx_fdget(fd);
338 if (IS_ERR(trigger)) {
339 kfree(vdev->ctx[vector].name);
340 return PTR_ERR(trigger);
341 }
342
343 /*
344 * The MSIx vector table resides in device memory which may be cleared
345 * via backdoor resets. We don't allow direct access to the vector
346 * table so even if a userspace driver attempts to save/restore around
347 * such a reset it would be unsuccessful. To avoid this, restore the
348 * cached value of the message prior to enabling.
349 */
350 if (msix) {
351 struct msi_msg msg;
352
353 get_cached_msi_msg(irq, &msg);
354 pci_write_msi_msg(irq, &msg);
355 }
356
357 ret = request_irq(irq, vfio_msihandler, 0,
358 vdev->ctx[vector].name, trigger);
359 if (ret) {
360 kfree(vdev->ctx[vector].name);
361 eventfd_ctx_put(trigger);
362 return ret;
363 }
364
365 vdev->ctx[vector].producer.token = trigger;
366 vdev->ctx[vector].producer.irq = irq;
367 ret = irq_bypass_register_producer(&vdev->ctx[vector].producer);
368 if (unlikely(ret))
369 dev_info(&pdev->dev,
370 "irq bypass producer (token %p) registration fails: %d\n",
371 vdev->ctx[vector].producer.token, ret);
372
373 vdev->ctx[vector].trigger = trigger;
374
375 return 0;
376 }
377
378 static int vfio_msi_set_block(struct vfio_pci_device *vdev, unsigned start,
379 unsigned count, int32_t *fds, bool msix)
380 {
381 int i, j, ret = 0;
382
383 if (start >= vdev->num_ctx || start + count > vdev->num_ctx)
384 return -EINVAL;
385
386 for (i = 0, j = start; i < count && !ret; i++, j++) {
387 int fd = fds ? fds[i] : -1;
388 ret = vfio_msi_set_vector_signal(vdev, j, fd, msix);
389 }
390
391 if (ret) {
392 for (--j; j >= (int)start; j--)
393 vfio_msi_set_vector_signal(vdev, j, -1, msix);
394 }
395
396 return ret;
397 }
398
399 static void vfio_msi_disable(struct vfio_pci_device *vdev, bool msix)
400 {
401 struct pci_dev *pdev = vdev->pdev;
402 int i;
403
404 vfio_msi_set_block(vdev, 0, vdev->num_ctx, NULL, msix);
405
406 for (i = 0; i < vdev->num_ctx; i++) {
407 vfio_virqfd_disable(&vdev->ctx[i].unmask);
408 vfio_virqfd_disable(&vdev->ctx[i].mask);
409 }
410
411 if (msix) {
412 pci_disable_msix(vdev->pdev);
413 kfree(vdev->msix);
414 } else
415 pci_disable_msi(pdev);
416
417 vdev->irq_type = VFIO_PCI_NUM_IRQS;
418 vdev->num_ctx = 0;
419 kfree(vdev->ctx);
420 }
421
422 /*
423 * IOCTL support
424 */
425 static int vfio_pci_set_intx_unmask(struct vfio_pci_device *vdev,
426 unsigned index, unsigned start,
427 unsigned count, uint32_t flags, void *data)
428 {
429 if (!is_intx(vdev) || start != 0 || count != 1)
430 return -EINVAL;
431
432 if (flags & VFIO_IRQ_SET_DATA_NONE) {
433 vfio_pci_intx_unmask(vdev);
434 } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
435 uint8_t unmask = *(uint8_t *)data;
436 if (unmask)
437 vfio_pci_intx_unmask(vdev);
438 } else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
439 int32_t fd = *(int32_t *)data;
440 if (fd >= 0)
441 return vfio_virqfd_enable((void *) vdev,
442 vfio_pci_intx_unmask_handler,
443 vfio_send_intx_eventfd, NULL,
444 &vdev->ctx[0].unmask, fd);
445
446 vfio_virqfd_disable(&vdev->ctx[0].unmask);
447 }
448
449 return 0;
450 }
451
452 static int vfio_pci_set_intx_mask(struct vfio_pci_device *vdev,
453 unsigned index, unsigned start,
454 unsigned count, uint32_t flags, void *data)
455 {
456 if (!is_intx(vdev) || start != 0 || count != 1)
457 return -EINVAL;
458
459 if (flags & VFIO_IRQ_SET_DATA_NONE) {
460 vfio_pci_intx_mask(vdev);
461 } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
462 uint8_t mask = *(uint8_t *)data;
463 if (mask)
464 vfio_pci_intx_mask(vdev);
465 } else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
466 return -ENOTTY; /* XXX implement me */
467 }
468
469 return 0;
470 }
471
472 static int vfio_pci_set_intx_trigger(struct vfio_pci_device *vdev,
473 unsigned index, unsigned start,
474 unsigned count, uint32_t flags, void *data)
475 {
476 if (is_intx(vdev) && !count && (flags & VFIO_IRQ_SET_DATA_NONE)) {
477 vfio_intx_disable(vdev);
478 return 0;
479 }
480
481 if (!(is_intx(vdev) || is_irq_none(vdev)) || start != 0 || count != 1)
482 return -EINVAL;
483
484 if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
485 int32_t fd = *(int32_t *)data;
486 int ret;
487
488 if (is_intx(vdev))
489 return vfio_intx_set_signal(vdev, fd);
490
491 ret = vfio_intx_enable(vdev);
492 if (ret)
493 return ret;
494
495 ret = vfio_intx_set_signal(vdev, fd);
496 if (ret)
497 vfio_intx_disable(vdev);
498
499 return ret;
500 }
501
502 if (!is_intx(vdev))
503 return -EINVAL;
504
505 if (flags & VFIO_IRQ_SET_DATA_NONE) {
506 vfio_send_intx_eventfd(vdev, NULL);
507 } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
508 uint8_t trigger = *(uint8_t *)data;
509 if (trigger)
510 vfio_send_intx_eventfd(vdev, NULL);
511 }
512 return 0;
513 }
514
515 static int vfio_pci_set_msi_trigger(struct vfio_pci_device *vdev,
516 unsigned index, unsigned start,
517 unsigned count, uint32_t flags, void *data)
518 {
519 int i;
520 bool msix = (index == VFIO_PCI_MSIX_IRQ_INDEX) ? true : false;
521
522 if (irq_is(vdev, index) && !count && (flags & VFIO_IRQ_SET_DATA_NONE)) {
523 vfio_msi_disable(vdev, msix);
524 return 0;
525 }
526
527 if (!(irq_is(vdev, index) || is_irq_none(vdev)))
528 return -EINVAL;
529
530 if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
531 int32_t *fds = data;
532 int ret;
533
534 if (vdev->irq_type == index)
535 return vfio_msi_set_block(vdev, start, count,
536 fds, msix);
537
538 ret = vfio_msi_enable(vdev, start + count, msix);
539 if (ret)
540 return ret;
541
542 ret = vfio_msi_set_block(vdev, start, count, fds, msix);
543 if (ret)
544 vfio_msi_disable(vdev, msix);
545
546 return ret;
547 }
548
549 if (!irq_is(vdev, index) || start + count > vdev->num_ctx)
550 return -EINVAL;
551
552 for (i = start; i < start + count; i++) {
553 if (!vdev->ctx[i].trigger)
554 continue;
555 if (flags & VFIO_IRQ_SET_DATA_NONE) {
556 eventfd_signal(vdev->ctx[i].trigger, 1);
557 } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
558 uint8_t *bools = data;
559 if (bools[i - start])
560 eventfd_signal(vdev->ctx[i].trigger, 1);
561 }
562 }
563 return 0;
564 }
565
566 static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
567 uint32_t flags, void *data)
568 {
569 int32_t fd = *(int32_t *)data;
570
571 if (!(flags & VFIO_IRQ_SET_DATA_TYPE_MASK))
572 return -EINVAL;
573
574 /* DATA_NONE/DATA_BOOL enables loopback testing */
575 if (flags & VFIO_IRQ_SET_DATA_NONE) {
576 if (*ctx)
577 eventfd_signal(*ctx, 1);
578 return 0;
579 } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
580 uint8_t trigger = *(uint8_t *)data;
581 if (trigger && *ctx)
582 eventfd_signal(*ctx, 1);
583 return 0;
584 }
585
586 /* Handle SET_DATA_EVENTFD */
587 if (fd == -1) {
588 if (*ctx)
589 eventfd_ctx_put(*ctx);
590 *ctx = NULL;
591 return 0;
592 } else if (fd >= 0) {
593 struct eventfd_ctx *efdctx;
594 efdctx = eventfd_ctx_fdget(fd);
595 if (IS_ERR(efdctx))
596 return PTR_ERR(efdctx);
597 if (*ctx)
598 eventfd_ctx_put(*ctx);
599 *ctx = efdctx;
600 return 0;
601 } else
602 return -EINVAL;
603 }
604
605 static int vfio_pci_set_err_trigger(struct vfio_pci_device *vdev,
606 unsigned index, unsigned start,
607 unsigned count, uint32_t flags, void *data)
608 {
609 if (index != VFIO_PCI_ERR_IRQ_INDEX)
610 return -EINVAL;
611
612 /*
613 * We should sanitize start & count, but that wasn't caught
614 * originally, so this IRQ index must forever ignore them :-(
615 */
616
617 return vfio_pci_set_ctx_trigger_single(&vdev->err_trigger, flags, data);
618 }
619
620 static int vfio_pci_set_req_trigger(struct vfio_pci_device *vdev,
621 unsigned index, unsigned start,
622 unsigned count, uint32_t flags, void *data)
623 {
624 if (index != VFIO_PCI_REQ_IRQ_INDEX || start != 0 || count != 1)
625 return -EINVAL;
626
627 return vfio_pci_set_ctx_trigger_single(&vdev->req_trigger, flags, data);
628 }
629
630 int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev, uint32_t flags,
631 unsigned index, unsigned start, unsigned count,
632 void *data)
633 {
634 int (*func)(struct vfio_pci_device *vdev, unsigned index,
635 unsigned start, unsigned count, uint32_t flags,
636 void *data) = NULL;
637
638 switch (index) {
639 case VFIO_PCI_INTX_IRQ_INDEX:
640 switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
641 case VFIO_IRQ_SET_ACTION_MASK:
642 func = vfio_pci_set_intx_mask;
643 break;
644 case VFIO_IRQ_SET_ACTION_UNMASK:
645 func = vfio_pci_set_intx_unmask;
646 break;
647 case VFIO_IRQ_SET_ACTION_TRIGGER:
648 func = vfio_pci_set_intx_trigger;
649 break;
650 }
651 break;
652 case VFIO_PCI_MSI_IRQ_INDEX:
653 case VFIO_PCI_MSIX_IRQ_INDEX:
654 switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
655 case VFIO_IRQ_SET_ACTION_MASK:
656 case VFIO_IRQ_SET_ACTION_UNMASK:
657 /* XXX Need masking support exported */
658 break;
659 case VFIO_IRQ_SET_ACTION_TRIGGER:
660 func = vfio_pci_set_msi_trigger;
661 break;
662 }
663 break;
664 case VFIO_PCI_ERR_IRQ_INDEX:
665 switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
666 case VFIO_IRQ_SET_ACTION_TRIGGER:
667 if (pci_is_pcie(vdev->pdev))
668 func = vfio_pci_set_err_trigger;
669 break;
670 }
671 break;
672 case VFIO_PCI_REQ_IRQ_INDEX:
673 switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
674 case VFIO_IRQ_SET_ACTION_TRIGGER:
675 func = vfio_pci_set_req_trigger;
676 break;
677 }
678 break;
679 }
680
681 if (!func)
682 return -ENOTTY;
683
684 return func(vdev, index, start, count, flags, data);
685 }
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